Difference between revisions of "Insulation"

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(Fire - refer to Grenfell Tower)
m (Straw - MICC cabling)
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'''Insulation''' reduces heat transfer, thus  
 
'''Insulation''' reduces heat transfer, thus  
* Reduces heat loss in winter, saving on [[heating]] costs and improving comfort
+
 
* Reduces rate of heat gain in summer, saving on ac costs.
+
*Reduces heat loss in winter, saving on [[heating]] costs and improving comfort
* Prevents freezing of [[Plumbing|pipes]]
+
*Reduces rate of heat gain in summer, saving on ac costs.
* Reduces run cost of [[Domestic Hot Water|hot water]] systems
+
*Prevents freezing of [[Plumbing|pipes]]
 +
*Reduces run cost of [[Domestic Hot Water|hot water]] systems
  
  
 
==Main DIY Applications==
 
==Main DIY Applications==
* Wall cavity insulation (for either original wall cavities or a retrofitted cavity behind [[plasterboard]])
+
 
* Solid [[wall]] insulation (fitted to wall surfaces)
+
*Wall cavity insulation (for either original wall cavities or a retrofitted cavity behind [[plasterboard]])
* Loft insulation
+
*Solid [[wall]] insulation (fitted to wall surfaces)
* [[Plumbing|Pipe]] insulation to prevent freezing or heat loss
+
*Loft insulation
* [[Domestic Hot Water|HW cylinder]] insulation
+
*[[Plumbing|Pipe]] insulation to prevent freezing or heat loss
* Under[[floor]] insulation
+
*[[Domestic Hot Water|HW cylinder]] insulation
 +
*Under[[floor]] insulation
  
 
==Forms of Insulation==
 
==Forms of Insulation==
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Low cost insulation available in
 
Low cost insulation available in
* slab form
+
 
* as small beads for loose fill & beanbags
+
*slab form
* shredded, cheaper than bead but less able to shed water
+
*as small beads for loose fill & beanbags
* larger chunks for packaging
+
*shredded, cheaper than bead but less able to shed water
 +
*larger chunks for packaging
  
 
Mainly used for:
 
Mainly used for:
* Roof insulation
+
 
* Wall insulation
+
*Roof insulation
* Floor insulation
+
*Wall insulation
 +
*Floor insulation
  
 
Polystyrene is flammable, and produces toxic smoke on burning. This problem is made worse when painted with [[oil]] based [[paint]]s.
 
Polystyrene is flammable, and produces toxic smoke on burning. This problem is made worse when painted with [[oil]] based [[paint]]s.
  
 
Sometimes used for cavity wall insulation
 
Sometimes used for cavity wall insulation
* Like any retrofit cavity insulation, it can saturate with [[water]] and cause [[:Category:Damp|damp problems]]
+
 
* Beads are generally [[glue]]d as they're injected, but in many cases the glue is omitted, and beads then pour out of any [[Drill bit|hole]] made in the wall
+
*Like any retrofit cavity insulation, it can saturate with [[water]] and cause [[:Category:Damp|damp problems]]
* No longer the favourite cavity filler
+
*Beads are generally [[glue]]d as they're injected, but in many cases the glue is omitted, and beads then pour out of any [[Drill bit|hole]] made in the wall
 +
*No longer the favourite cavity filler
  
 
Polystyrene in wall cavities is relatively well protected from [[fire]], and is not considered a fire safety issue. However if PVC electrical [[cable]] is fitted in the wall cavity, as is occasionally done, polystyrene cavity insulation in contact with it causes the cable to leach plasticiser and become unsafe.
 
Polystyrene in wall cavities is relatively well protected from [[fire]], and is not considered a fire safety issue. However if PVC electrical [[cable]] is fitted in the wall cavity, as is occasionally done, polystyrene cavity insulation in contact with it causes the cable to leach plasticiser and become unsafe.
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====Ceiling tiles====
 
====Ceiling tiles====
 
Insulating decorative ceiling tiles
 
Insulating decorative ceiling tiles
* Dangerous in a fire
+
 
* Spreads fire rapidly
+
*Dangerous in a fire
* Generates thick toxic smoke when burnt
+
*Spreads fire rapidly
* Gloss [[paint]]ing them makes them even worse for flammability
+
*Generates thick toxic smoke when burnt
* Ugly
+
*Gloss [[paint]]ing them makes them even worse for flammability
* Best removed on safety grounds
+
*Ugly
 +
*Best removed on safety grounds
  
  
 
====Polystyrene veneer====
 
====Polystyrene veneer====
 
A thin crack covering layer on walls a few mm thick
 
A thin crack covering layer on walls a few mm thick
* Primarily used to stop [[Damp|condensation]], and sometimes cover bad cracking
+
 
* Dents very readily
+
*Primarily used to stop [[Damp|condensation]], and sometimes cover bad cracking
* Grim news in a fire
+
*Dents very readily
* Best removed on safety grounds
+
*Grim news in a fire
 +
*Best removed on safety grounds
  
 
===Fibreglass===
 
===Fibreglass===
 
[[image:Fibreglass insulation 5662-8.jpg|right|200px]]
 
[[image:Fibreglass insulation 5662-8.jpg|right|200px]]
  
* Comes in roll form, as loose fill and as semi-rigid batts
+
*Comes in roll form, as loose fill and as semi-rigid batts
* Lasts the life of the building no matter what life throws at it.
+
*Lasts the life of the building no matter what life throws at it.
* Waterproof
+
*Waterproof
* Insectproof
+
*Insectproof
* Verminproof
+
*Verminproof
* Fireproof
+
*Fireproof
* Springs back to shape if squashed
+
*Springs back to shape if squashed
* Lightweight
+
*Lightweight
* Loosefill fibreglass can be blown about in a draughty loft
+
*Loosefill fibreglass can be blown about in a draughty loft
* Produces prodigious loose glass fibres
+
*Produces prodigious loose glass fibres
* Tiny spiky glass fibres cause splinters
+
*Tiny spiky glass fibres cause splinters
* Concerns about its safety are occasionally expressed on the basis that it releases miniature sharp spikey non-dissolving airborne fibres, somewhat like known carcinogenic forms of asbestos. Fibreglass gradually dissolves in the lung, so doesn't pose the same risk
+
*Concerns about its safety are occasionally expressed on the basis that it releases miniature sharp spikey non-dissolving airborne fibres, somewhat like known carcinogenic forms of asbestos. Fibreglass gradually dissolves in the lung, so doesn't pose the same risk
* Dust mask should be used during handling
+
*Dust mask should be used during handling
* Gloves are also recommended to reduce splinters
+
*Gloves are also recommended to reduce splinters
* Compressing a layer to improve insulation should be avoided. Squashing 6" down to 4" gives you about the insulation value of 4" of fibreglass, and the pressure can damage [[plasterboard]].
+
*Compressing a layer to improve insulation should be avoided. Squashing 6" down to 4" gives you about the insulation value of 4" of fibreglass, and the pressure can damage [[plasterboard]].
* Much used for loft insulation
+
*Much used for loft insulation
* Not a great choice in a windy position, wind can blow through it
+
*Not a great choice in a windy position, wind can blow through it
  
 
===Rockwool===
 
===Rockwool===
 
A mineral fibre very similar to glass fibre, but denser, so much less airborne fibre.
 
A mineral fibre very similar to glass fibre, but denser, so much less airborne fibre.
* Popularly used for loft insulation & internal [[stud wall]]s
+
 
* Comes in [[Roll Materials|roll form]], as loose fill and as semi-rigid batts
+
*Popularly used for loft insulation & internal [[stud wall]]s
 +
*Comes in [[Roll Materials|roll form]], as loose fill and as semi-rigid batts
  
 
===Polyisocyanurate===
 
===Polyisocyanurate===
 
[[image:Celotex 4644-4.jpg|right|150px]]
 
[[image:Celotex 4644-4.jpg|right|150px]]
  
* Rigid foamed boards
+
*Rigid foamed boards
* High R value per thickness
+
*High R value per thickness
* Good choice for lining walls
+
*Good choice for lining walls
* Kingspan & Celotex are the leading manufacturers
+
*Kingspan & Celotex are the leading manufacturers
* Seconds with minor defects are cheaper
+
*Seconds with minor defects are cheaper
* Survives temperatures upto 400C
+
*Survives temperatures upto 400C
  
 
===Cellulose===
 
===Cellulose===
 
[[image:Cellulose insulation 1626-3.jpg|right|200px]]
 
[[image:Cellulose insulation 1626-3.jpg|right|200px]]
* Low cost
+
 
* Loose fill
+
*Low cost
* Used in cavities
+
*Loose fill
* Plant fibre
+
*Used in cavities
* Made from ground newspaper
+
*Plant fibre
* Better performance than fibreglass
+
*Made from ground newspaper
* Slumps a bit over time, so not suitable for wall cavities
+
*Better performance than fibreglass
* [http://en.wikipedia.org/wiki/Cellulose_insulation wikipedia]
+
*Slumps a bit over time, so not suitable for wall cavities
* Appliable wet or dry - dry is more common for diy
+
*[http://en.wikipedia.org/wiki/Cellulose_insulation wikipedia]
 +
*Appliable wet or dry - dry is more common for diy
  
 
Wet sprayed cellulose insulation:
 
Wet sprayed cellulose insulation:
* Sticks itself in position
+
 
* Same insulation value as loose fill
+
*Sticks itself in position
* Doesn't slump
+
*Same insulation value as loose fill
* Must dry out before being boarded over
+
*Doesn't slump
 +
*Must dry out before being boarded over
  
 
===Fibreboard===
 
===Fibreboard===
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Used under timber floors  
 
Used under timber floors  
* thermal insulation
+
 
* [[Noise|sound absorbing]]
+
*thermal insulation
* slight springiness
+
*[[Noise|sound absorbing]]
* 3mm & 6mm common
+
*slight springiness
* breaks easily
+
*3mm & 6mm common
 +
*breaks easily
  
 
===Neoprene pipe insulation===
 
===Neoprene pipe insulation===
 
[[image:Neoprene pipe insulation 5662-4.jpg|right|200px]]
 
[[image:Neoprene pipe insulation 5662-4.jpg|right|200px]]
  
* Foam-like tube pre-slit down one side
+
*Foam-like tube pre-slit down one side
* very easy to apply
+
*very easy to apply
* [[Tape]] the slit shut or its much less effective
+
*[[Tape]] the slit shut or its much less effective
* Corners in pipes are dealt with by cutting the 2 lengths of neoprene at 45 degrees
+
*Corners in pipes are dealt with by cutting the 2 lengths of neoprene at 45 degrees
* [[Tape]] the end gaps between lengths of insulation, and any other gaps or joints such as at corners
+
*[[Tape]] the end gaps between lengths of insulation, and any other gaps or joints such as at corners
  
 
===Felt===
 
===Felt===
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Felt strip is used as pipe lagging
 
Felt strip is used as pipe lagging
* Its wound around the pipe(s) and secured with [[Tapes|tape]] or a cable tie (don't squash the felt much)
+
 
* Brown, hairy and untidy
+
*Its wound around the pipe(s) and secured with [[Tapes|tape]] or a cable tie (don't squash the felt much)
* Best used for [[Plumbing|pipes]] out of sight
+
*Brown, hairy and untidy
* Good for insulating grouped pipes, where foam jackets don't fit
+
*Best used for [[Plumbing|pipes]] out of sight
* Can be used for pretty much any shape and size of pipework
+
*Good for insulating grouped pipes, where foam jackets don't fit
* Foam tube is much quicker for insulating single pipes
+
*Can be used for pretty much any shape and size of pipework
 +
*Foam tube is much quicker for insulating single pipes
  
  
 
===PVC Cladding===
 
===PVC Cladding===
* Mainly used on gable wall ends
+
 
* Keeps rain off the wall as well as insulating
+
*Mainly used on gable wall ends
* Can make a messy wall look ok too, but not the world's favourite finish
+
*Keeps rain off the wall as well as insulating
* Sometimes seen used internally, but tends to become hard to clean over time due to surface roughening, and not a popular finish even when new.
+
*Can make a messy wall look ok too, but not the world's favourite finish
 +
*Sometimes seen used internally, but tends to become hard to clean over time due to surface roughening, and not a popular finish even when new.
  
  
 
===Timber cladding===
 
===Timber cladding===
* Timber cladding is used as an interior and exterior finish
+
 
* Provides a small amount of insulation
+
*Timber cladding is used as an interior and exterior finish
* Several timber designs available
+
*Provides a small amount of insulation
* If fitting it anew, sheet insulation can go under the cladding
+
*Several timber designs available
 +
*If fitting it anew, sheet insulation can go under the cladding
  
  
 
===Insulating render mixes===
 
===Insulating render mixes===
 
[[Cement]] mixes containing polystyrene beads, leca or vermiculite
 
[[Cement]] mixes containing polystyrene beads, leca or vermiculite
* Fireproof
+
 
* [[Paint]] to prevent [[water]] ingress and freeze/thaw damage
+
*Fireproof
* You can't have it all, to get fair insulation value the mix needs to be high in insulation beads, making it much weaker than concrete
+
*[[Paint]] to prevent [[water]] ingress and freeze/thaw damage
 +
*You can't have it all, to get fair insulation value the mix needs to be high in insulation beads, making it much weaker than concrete
  
  
 
===Shredded Paper===
 
===Shredded Paper===
* Sometimes used as loose fill loft insulation
+
 
* Waste paper is treated with fire retardant and chopped or shredded.
+
*Sometimes used as loose fill loft insulation
* Recycled
+
*Waste paper is treated with fire retardant and chopped or shredded.
* Not [[:Category:Damp|damp]] tolerant
+
*Recycled
 +
*Not [[:Category:Damp|damp]] tolerant
  
  
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[[image:Cardboard 1in 4473-3.jpg|right|150px]]
 
[[image:Cardboard 1in 4473-3.jpg|right|150px]]
  
* Very low cost insulation material
+
*Very low cost insulation material
* Rapid return on investment
+
*Rapid return on investment
* Fitting used cardboard results in zero extra manufacturing energy use.
+
*Fitting used cardboard results in zero extra manufacturing energy use.
* Cardboard wall insulation is popular in the US, but seems to have had little takeup here in the UK.
+
*Cardboard wall insulation is popular in the US, but seems to have had little takeup here in the UK.
* Its flammability can be resolved by painting it with a mixture of borax & boric acid.
+
*Its flammability can be resolved by painting it with a mixture of borax & boric acid.
* Its damp susceptible, and can support [[Mould Basics|mould]] if damp
+
*Its damp susceptible, and can support [[Mould Basics|mould]] if damp
* Should not be used in situations where damp may occur.
+
*Should not be used in situations where damp may occur.
* Available free
+
*Available free
  
  
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===Sheep's Wool===
 
===Sheep's Wool===
 
Sometimes used instead of fibreglass or rockwool.
 
Sometimes used instead of fibreglass or rockwool.
* Non-irritant, no protective clothes required.
+
 
* Costs more than fibreglass & rockwool
+
*Non-irritant, no protective clothes required.
* Cheap if you or a nearby sheep farmer has wool they can't sell, unwashed wool is not allowed to be used
+
*Costs more than fibreglass & rockwool
* Insulation value low compared with PIR
+
*Cheap if you or a nearby sheep farmer has wool they can't sell, unwashed wool is not allowed to be used
* This can result in excessive depth requirements in new builds, affecting ceiling height etc
+
*Insulation value low compared with PIR
* Life 50+ years
+
*This can result in excessive depth requirements in new builds, affecting ceiling height etc
* Biodegradable
+
*Life 50+ years
* Chars, but doesn't spread [[fire]]
+
*Biodegradable
* Treated against [[:Category:Pests|insects]]
+
*Chars, but doesn't spread [[fire]]
 +
*Treated against [[:Category:Pests|insects]]
  
 
===Straw===
 
===Straw===
 
Straw has long been used as insulation, and is another low cost option.
 
Straw has long been used as insulation, and is another low cost option.
* Susceptible to damp & [[mould]], but less so than cardboard
+
 
* Nest material for birds
+
*Susceptible to damp & [[mould]], but less so than cardboard
* Can contain unhatched [[:Category:Pests|insect eggs]]
+
*Nest material for birds
* Flammable, which can be resolved by [[Plastering Beginner's Guide|plastering]] over the straw to deny the admittance of air for combustion.
+
*Can contain unhatched [[:Category:Pests|insect eggs]]
* Low cost
+
*Flammable, which can be resolved by [[Plastering Beginner's Guide|plastering]] over the straw to deny the admittance of air for combustion.
* Used to be available in slab form, this is occasionally seen in use.
+
*Low cost
* Insulation value per inch isn't great, works best where it can be applied thickly
+
*Used to be available in slab form, this is occasionally seen in use.
 +
*Insulation value per inch isn't great, works best where it can be applied thickly
 +
*Insurers may require [[MICC cabling]] in straw bale house construction
  
  
 
===Clay beads===
 
===Clay beads===
 
LECA expanded clay beads are occasionally used as house insulation.
 
LECA expanded clay beads are occasionally used as house insulation.
* Non-flammable
+
 
* Unaffected by damp
+
*Non-flammable
* Used as loose fill, mainly under floors
+
*Unaffected by damp
 +
*Used as loose fill, mainly under floors
  
  
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Only rarely used in houses, wrapped round water tanks or used as an insulating window blind.
 
Only rarely used in houses, wrapped round water tanks or used as an insulating window blind.
* Degraded by UV light over time.
+
 
* Flammable
+
*Degraded by UV light over time.
* Used as greenhouse secondary glazing
+
*Flammable
* May last ok in dark places eg lofts & cupboards.
+
*Used as greenhouse secondary glazing
 +
*May last ok in dark places eg lofts & cupboards.
  
  
 
===Foamed Concrete===
 
===Foamed Concrete===
* Lightweight concrete blocks have insulation value
+
 
* Insulation is one of the reasons for their use as the interior leaf of exterior walls
+
*Lightweight concrete blocks have insulation value
* They don't survive outdoors unless rendered.
+
*Insulation is one of the reasons for their use as the interior leaf of exterior walls
* The light weight makes construction quicker
+
*They don't survive outdoors unless rendered.
 +
*The light weight makes construction quicker
  
 
===Aerogel===
 
===Aerogel===
* Aerogel is a very low density glass/air gel rated at 0.013 W/mK
+
 
* High temperature resistance
+
*Aerogel is a very low density glass/air gel rated at 0.013 W/mK
* Its steep price restricts it to applications where high insulation value per size & high temperature rating are necessary. This does not include house insulation.
+
*High temperature resistance
* Sold by [http://www.spacetherm.com/products.htm Spacetherm].
+
*Its steep price restricts it to applications where high insulation value per size & high temperature rating are necessary. This does not include house insulation.
 +
*Sold by [http://www.spacetherm.com/products.htm Spacetherm].
  
 
===Bottles===
 
===Bottles===
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Issues:
 
Issues:
* A whole lot of bottles needed
+
 
* Bottles can be vandalised, but in practice such buildings are normally well appreciated and not vandalised
+
*A whole lot of bottles needed
* In principle, differential thermal expansion and ASR can both crack bottle walls, in practice they work ok though
+
*Bottles can be vandalised, but in practice such buildings are normally well appreciated and not vandalised
 +
*In principle, differential thermal expansion and ASR can both crack bottle walls, in practice they work ok though
  
  
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[[image:Expanding foam & tape tube extension 4661-4.jpg|right|110px]]
 
[[image:Expanding foam & tape tube extension 4661-4.jpg|right|110px]]
  
* Comes in squirty cans
+
*Comes in squirty cans
* See [[Expanding foam]] for fuller information
+
*See [[Expanding foam]] for fuller information
* Mainly used to fill gaps in sheet insulation, to stick [[plasterboard]] up, and to fill odd shaped holes
+
*Mainly used to fill gaps in sheet insulation, to stick [[plasterboard]] up, and to fill odd shaped holes
* Some foams expand a lot, some a little
+
*Some foams expand a lot, some a little
* Beware, some generate very high forces as they expand after setting, enough force to bring [[wall]]s down
+
*Beware, some generate very high forces as they expand after setting, enough force to bring [[wall]]s down
* [http://groups.google.com/group/uk.d-i-y/browse_frm/thread/66ffca1fab79b30f# Half pound vs 2 pound foams]
+
*[http://groups.google.com/group/uk.d-i-y/browse_frm/thread/66ffca1fab79b30f# Half pound vs 2 pound foams]
* [http://www.diyfaq.org.uk/humour.html#foam Cautionary tale]
+
*[http://www.diyfaq.org.uk/humour.html#foam Cautionary tale]
  
  
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===Cork===
 
===Cork===
 
[[image:Cork 2824-2.jpg|right|120px]]
 
[[image:Cork 2824-2.jpg|right|120px]]
* Formerly used for insulation, but not much
+
 
* Prone to rot & coming unstuck over time
+
*Formerly used for insulation, but not much
* The main use is for floorcovering
+
*Prone to rot & coming unstuck over time
 +
*The main use is for floorcovering
  
 
===Asbestos===
 
===Asbestos===
* An obsolete insulator with safety problems
+
 
* Sometimes needs removing for safety, but more often not
+
*An obsolete insulator with safety problems
* See [[Asbestos]]
+
*Sometimes needs removing for safety, but more often not
 +
*See [[Asbestos]]
  
 
===Multifoil===
 
===Multifoil===
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==Unsatisfactory Insulation Materials==
 
==Unsatisfactory Insulation Materials==
 
[[Carpet]]
 
[[Carpet]]
* Too thin to give much insulation
+
 
* Flammable
+
*Too thin to give much insulation
* Reduces draughts
+
*Flammable
 +
*Reduces draughts
  
 
Polystyrene ceiling tiles & wallpaper
 
Polystyrene ceiling tiles & wallpaper
* Too thin to give much benefit
+
 
* Very flammable, spreads fire & produces toxic smoke
+
*Too thin to give much benefit
* Dents very easily
+
*Very flammable, spreads fire & produces toxic smoke
 +
*Dents very easily
  
 
Sand
 
Sand
* Traps air but is thermally conductive
+
 
 +
*Traps air but is thermally conductive
  
 
Bubblewrap
 
Bubblewrap
* Degrades quickly from UV exposure
+
 
 +
*Degrades quickly from UV exposure
  
 
[[Spray-on Roof Insulation]]
 
[[Spray-on Roof Insulation]]
* Traps water, prone to causing [[Wood Rot|rot]]
+
 
* Makes the roofcovering non-reusable
+
*Traps water, prone to causing [[Wood Rot|rot]]
 +
*Makes the roofcovering non-reusable
  
  
 
==Free insulation options==
 
==Free insulation options==
* Cardboard sheet
+
 
* Waste polystyrene
+
*Cardboard sheet
* Straw
+
*Waste polystyrene
* Bubblewrap for water tanks & cylinders
+
*Straw
* Scrap clothing as pipe insulation
+
*Bubblewrap for water tanks & cylinders
 +
*Scrap clothing as pipe insulation
  
  
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===Loft===
 
===Loft===
 
Deep insulation is usually fine in a loft, so the ideal properties are low cost per insulation value, and easily laid roll insulation. The 2 main candidates are
 
Deep insulation is usually fine in a loft, so the ideal properties are low cost per insulation value, and easily laid roll insulation. The 2 main candidates are
* Rockwool  
+
 
* Fibreglass
+
*Rockwool
 +
*Fibreglass
  
 
Less often used:
 
Less often used:
* Shredded or chopped fire retardant treated paper
+
 
* Sheep's wool (available in batts as Thermafleece or rolls from www.BlackMountainInsulation.com)
+
*Shredded or chopped fire retardant treated paper
 +
*Sheep's wool (available in batts as Thermafleece or rolls from www.BlackMountainInsulation.com)
  
 
Where insulation exceeds the depth of the [[joist]]s and no [[floor]] is fitted, best practice is to fit the insulation in 2 layers, with the 2nd layer at 90 degrees to the first. This minimises any gaps and helps ensure the joists are completely covered too.
 
Where insulation exceeds the depth of the [[joist]]s and no [[floor]] is fitted, best practice is to fit the insulation in 2 layers, with the 2nd layer at 90 degrees to the first. This minimises any gaps and helps ensure the joists are completely covered too.
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When a [[floor]] will be fitted and its desired to use more insulation than the current depth of the joists, there are 2 options.
 
When a [[floor]] will be fitted and its desired to use more insulation than the current depth of the joists, there are 2 options.
# The best is to add more timber along the top of the existing joists to deepen them, gluing and [[screw]]ing it in place. This provides space and greatly [[http://wiki.diyfaq.org.uk/index.php?title=Strengthen_a_Wood_Floor|strengthens & stiffens the floor stucture]].
+
 
# The simpler option is to insulate the existing depth, fit the floor, then lay out more [[roll]] insulation on top of the floor. This can be rolled back or just left in situ when boxes are placed there.
+
#The best is to add more timber along the top of the existing joists to deepen them, gluing and [[screw]]ing it in place. This provides space and greatly [[http://wiki.diyfaq.org.uk/index.php?title=Strengthen_a_Wood_Floor|strengthens & stiffens the floor stucture]].
# Fit little supports for the floor, so it sits higher than the joists. Can be done with pieces of timber or little stands can be bought for the job.
+
#The simpler option is to insulate the existing depth, fit the floor, then lay out more [[roll]] insulation on top of the floor. This can be rolled back or just left in situ when boxes are placed there.
 +
#Fit little supports for the floor, so it sits higher than the joists. Can be done with pieces of timber or little stands can be bought for the job.
  
 
===Roof===
 
===Roof===
 
The choice of roof insulation is mostly determined by depth. Lower cost insulators need more depth for BR compliance.
 
The choice of roof insulation is mostly determined by depth. Lower cost insulators need more depth for BR compliance.
* Polystyrene sheet - cheap
+
 
* Polyisocyanurate - where depth of insulation needs to be minimised, not cheap
+
*Polystyrene sheet - cheap
* Sheep's wool - requires a whole lot of depth to meet BR
+
*Polyisocyanurate - where depth of insulation needs to be minimised, not cheap
 +
*Sheep's wool - requires a whole lot of depth to meet BR
  
  
 
===Cavity Wall Insulation===
 
===Cavity Wall Insulation===
 
Fitted to existing original wall cavities:
 
Fitted to existing original wall cavities:
* Rockwool
+
 
* Fibreglass
+
*Rockwool
* Polystyrene bead
+
*Fibreglass
 +
*Polystyrene bead
  
 
Fitted to retrofitted cavities:
 
Fitted to retrofitted cavities:
* Polystyrene slab
+
 
* Fibreglass
+
*Polystyrene slab
* Rockwool batts
+
*Fibreglass
* Polyisocyanurate
+
*Rockwool batts
 +
*Polyisocyanurate
  
  
 
===Solid Insulation for Walls===
 
===Solid Insulation for Walls===
 
Fitted to the surface of solid walls (and occasionally to cavity walls) to increase insulation level further.
 
Fitted to the surface of solid walls (and occasionally to cavity walls) to increase insulation level further.
* Polyisocyanurate (PIR)
+
 
* Polystyrene foam backed plasterboard sheets may also be used, but don't provide very good insulation per thickness.
+
*Polyisocyanurate (PIR)
* Cheap roll insulation may be used, eg rockwool, if battens are fitted and plasterboarded. However sheet PIR without studs gives much better insulation.
+
*Polystyrene foam backed plasterboard sheets may also be used, but don't provide very good insulation per thickness.
* Hard surfaced insulating sheets. These have an extremely thin reinforced cement surface, so almost all their depth is insulation, but they're expensive
+
*Cheap roll insulation may be used, eg rockwool, if battens are fitted and plasterboarded. However sheet PIR without studs gives much better insulation.
 +
*Hard surfaced insulating sheets. These have an extremely thin reinforced cement surface, so almost all their depth is insulation, but they're expensive
  
  
 
===Tanks & Cylinders===
 
===Tanks & Cylinders===
 
The standard options for hot water cylinder insulation are:
 
The standard options for hot water cylinder insulation are:
* jacket retrofitted - an improvement
+
 
* foam coated cylinder - much better
+
*jacket retrofitted - an improvement
 +
*foam coated cylinder - much better
  
 
Its also possible to create a container around the cylinder and fill the gap with insulation. In a typical airing cupboard this only requires hardboard across the front, and the space may be filled with any type of standard building insulation, or simply with free garbage of any insulating type, such as parcel packaging, cardboard & bubblewrap.
 
Its also possible to create a container around the cylinder and fill the gap with insulation. In a typical airing cupboard this only requires hardboard across the front, and the space may be filled with any type of standard building insulation, or simply with free garbage of any insulating type, such as parcel packaging, cardboard & bubblewrap.
* Minimise the amount of [[immersion heater]] flex that gets buried in insulation.
+
 
 +
*Minimise the amount of [[immersion heater]] flex that gets buried in insulation.
  
  
Line 426: Line 467:
  
 
==R & U Values==
 
==R & U Values==
* R is a measure of resistance to heat flow, ie insulation
+
 
* U is a measure of heat conductance
+
*R is a measure of resistance to heat flow, ie insulation
* R value = 1/ U value
+
*U is a measure of heat conductance
 +
*R value = 1/ U value
  
 
U is measured in watts per square metre per centigrade (W / m^2 C)
 
U is measured in watts per square metre per centigrade (W / m^2 C)
* The temperature figure is the temperature difference between the 2 sides of the insulation rather than ambient temperature
+
 
* W/m^2 k is more widely quoted, but has exactly the same value as above
+
*The temperature figure is the temperature difference between the 2 sides of the insulation rather than ambient temperature
* Beware of American R figures being quoted in completely different units
+
*W/m^2 k is more widely quoted, but has exactly the same value as above
 +
*Beware of American R figures being quoted in completely different units
  
 
To determine a figure for multiple elements in series (which is how most walls are composed), just add up the R values of each element.
 
To determine a figure for multiple elements in series (which is how most walls are composed), just add up the R values of each element.
Line 442: Line 485:
  
 
Masonry
 
Masonry
* Brick: R = 0.03 per 25mm
 
* Single brick (4") R = 0.12
 
* Solid brick 9" 0.44
 
* Concrete 0.015 per 25mm
 
* Limestone R = 0.017 per 25mm
 
* Cavity wall: 0.53
 
* 4" AAC wall: 0.78
 
  
* Lime plaster R = .05 per 25mm
+
*Brick: R = 0.03 per 25mm
 +
*Single brick (4") R = 0.12
 +
*Solid brick 9" 0.44
 +
*Concrete 0.015 per 25mm
 +
*Limestone R = 0.017 per 25mm
 +
*Cavity wall: 0.53
 +
*4" AAC wall: 0.78
  
* Unventilated Cavity R = 0.18
+
*Lime plaster R = .05 per 25mm
* Outside air bounday layer = .03
 
* Inside air boundary layer = .12
 
  
* Aerated cement block  
+
*Unventilated Cavity R = 0.18
 +
*Outside air bounday layer = .03
 +
*Inside air boundary layer = .12
 +
 
 +
*Aerated cement block
  
 
Wood
 
Wood
* Softwood typically 0.25 per 25mm
+
 
* Timber cladding typ 0.44 for 25mm
+
*Softwood typically 0.25 per 25mm
 +
*Timber cladding typ 0.44 for 25mm
  
 
Insulation materials
 
Insulation materials
* Marmox R= 0.75 per 25mm
 
* Kingspan R = 1.08 per 25mm
 
  
* Celotex R= 1.31 per 25mm
+
*Marmox R= 0.75 per 25mm
* Thermafleece (treated sheep's wool) R = 0.65 per 25mm
+
*Kingspan R = 1.08 per 25mm
  
* Expanded polystyrene slab 0.63 - 0.88 (loose fill value is lower)
+
*Celotex R= 1.31 per 25mm
* Fibreglass loosefill R = 0.45 per 25mm
+
*Thermafleece (treated sheep's wool) R = 0.65 per 25mm
* Fibreglass batt 0.55-0.76 per 25mm
+
 
* Straw bale 0.26 per 25mm
+
*Expanded polystyrene slab 0.63 - 0.88 (loose fill value is lower)
* Vermiculite loose fill 0.4 per 25mm
+
*Fibreglass loosefill R = 0.45 per 25mm
* Pearlite 0.48 per 25mm
+
*Fibreglass batt 0.55-0.76 per 25mm
* Rockwool loosefill 0.44-0.65 per 25mm
+
*Straw bale 0.26 per 25mm
* Rockwool batts 0.52-0.68 per 25mm
+
*Vermiculite loose fill 0.4 per 25mm
* Cellulose 0.52-0.67 per 25mm (for both dry & wet sprayed)
+
*Pearlite 0.48 per 25mm
* Polyurethane panel 0.97 - 1.2 per 25mm
+
*Rockwool loosefill 0.44-0.65 per 25mm
* Polyurethane expanding foam: same
+
*Rockwool batts 0.52-0.68 per 25mm
* Foil faced polyisocyanurate panel 0.97 - 1.2 per 25mm
+
*Cellulose 0.52-0.67 per 25mm (for both dry & wet sprayed)
* Cotton batt:  
+
*Polyurethane panel 0.97 - 1.2 per 25mm
* Aerogel 1.76 per 25mm
+
*Polyurethane expanding foam: same
* Vacuum 5.28 per 25mm
+
*Foil faced polyisocyanurate panel 0.97 - 1.2 per 25mm
* Cardboard 0.52 per 25mm
+
*Cotton batt:
* Wood chips and similar products R=0.18 per 25mm
+
*Aerogel 1.76 per 25mm
 +
*Vacuum 5.28 per 25mm
 +
*Cardboard 0.52 per 25mm
 +
*Wood chips and similar products R=0.18 per 25mm
  
 
Note that some insulation types have R values that deteriorate a bit over time due to compaction or loss of their insulating gas component. This is primarily true for polyisocyanurate(PIR), gas filled double glazing and vacuum panels.
 
Note that some insulation types have R values that deteriorate a bit over time due to compaction or loss of their insulating gas component. This is primarily true for polyisocyanurate(PIR), gas filled double glazing and vacuum panels.
Line 491: Line 537:
  
 
Windows
 
Windows
* Window, single glazed: 0.18
+
 
* Window, double glazed: 0.35
+
*Window, single glazed: 0.18
** can be improved to over 0.5 with noble gas fill & glass coatings
+
*Window, double glazed: 0.35
* Note thicker glass makes no noticeable difference to R value
+
**can be improved to over 0.5 with noble gas fill & glass coatings
* Window, triple glazed: 0.52
+
*Note thicker glass makes no noticeable difference to R value
* Thermal lined close fitting curtains & pelmet: 0.3
+
*Window, triple glazed: 0.52
* Roller blind: 0.18
+
*Thermal lined close fitting curtains & pelmet: 0.3
 +
*Roller blind: 0.18
  
 
Other materials:
 
Other materials:
 +
 
*Earth R=0.58
 
*Earth R=0.58
 
*Weatherboard wall: 0.55
 
*Weatherboard wall: 0.55
Line 511: Line 559:
 
==Cold Bridging==
 
==Cold Bridging==
 
A common issue with insulation is cold bridging. This is where there are patches that aren't insulted like the rest. Causes are:
 
A common issue with insulation is cold bridging. This is where there are patches that aren't insulted like the rest. Causes are:
* Gaps left in the insulation
+
 
* Places where insulation changes from interior to exterior
+
*Gaps left in the insulation
* Places where existing building materials prevent fitting of insulation. Some examples are:
+
*Places where insulation changes from interior to exterior
** insulation sheet fitted into a timber frame, leaving the frame itself uninsulated
+
*Places where existing building materials prevent fitting of insulation. Some examples are:
** Cavity wall insulation unable to insulate around windows, due to lintel above, and existing masonry on all sides
+
**insulation sheet fitted into a timber frame, leaving the frame itself uninsulated
** Plasterboarded battens with insulation fitted between battens
+
**Cavity wall insulation unable to insulate around windows, due to lintel above, and existing masonry on all sides
 +
**Plasterboarded battens with insulation fitted between battens
  
 
Cold bridging also has the potential to cause a [[:Category:Damp|damp problem]]. Where previously either no condensation occurred, or it occurred over a large area and evaporated fairly quickly without incident, after insulation condensation can concentrate onto relatively small cold bridges and cause [[Mould basics|mould]] or fabric damage. This isn't normally a problem, but can be.
 
Cold bridging also has the potential to cause a [[:Category:Damp|damp problem]]. Where previously either no condensation occurred, or it occurred over a large area and evaporated fairly quickly without incident, after insulation condensation can concentrate onto relatively small cold bridges and cause [[Mould basics|mould]] or fabric damage. This isn't normally a problem, but can be.
Line 531: Line 580:
  
 
A stack of the following may be used, in this order:
 
A stack of the following may be used, in this order:
* heat source (eg spotlight)
+
 
* top metal plate to spread heat out evenly
+
*heat source (eg spotlight)
* an insulation material of known value (R1)
+
*top metal plate to spread heat out evenly
* insulation material under test (R2)
+
*an insulation material of known value (R1)
* bottom metal plate to spread heat out evenly
+
*insulation material under test (R2)
 +
*bottom metal plate to spread heat out evenly
  
 
Thermometers or thermocouples are added at the 3 insulation boundaries, at
 
Thermometers or thermocouples are added at the 3 insulation boundaries, at
* top metal plate
+
 
* bottom metal plate
+
*top metal plate
* the interface between the 2 insulation layers
+
*bottom metal plate
 +
*the interface between the 2 insulation layers
  
 
Thick high insulation value material is added around the 4 sides of the stack. The stack bottom is left uninsulated.
 
Thick high insulation value material is added around the 4 sides of the stack. The stack bottom is left uninsulated.
Line 547: Line 598:
  
 
The insulation value of the unknown layer is determined from the ratio of thermal resistance (insulation) values. Where the resistances are R1 and R2:
 
The insulation value of the unknown layer is determined from the ratio of thermal resistance (insulation) values. Where the resistances are R1 and R2:
: middle interface temp - bottom plate temp = (top plate temp - bottom plate temp) x R2/(R1+R2)
+
 
 +
:middle interface temp - bottom plate temp = (top plate temp - bottom plate temp) x R2/(R1+R2)
  
 
Most accurate results are obtained when the insulation values of the 2 layers are in the same ballpark, and top plate temp is high. For accuracy, avoid using results where the middle interface temp is close to top or bottom plate temp, or the top plate temp is low.
 
Most accurate results are obtained when the insulation values of the 2 layers are in the same ballpark, and top plate temp is high. For accuracy, avoid using results where the middle interface temp is close to top or bottom plate temp, or the top plate temp is low.
  
 
Self testing is only sufficient for applications where BR approval is not required. To obtain BCO approval with non-standard materials requires the test results and building insulation design to be signed off by an engineer. Other aspects of insulation also need to be considered in this
 
Self testing is only sufficient for applications where BR approval is not required. To obtain BCO approval with non-standard materials requires the test results and building insulation design to be signed off by an engineer. Other aspects of insulation also need to be considered in this
* ability to survive damp
+
 
* rotproofness
+
*ability to survive damp
* fire performance
+
*rotproofness
* longevity
+
*fire performance
* insectproofness
+
*longevity
* and rarely toxicity
+
*insectproofness
 +
*and rarely toxicity
  
  
Line 563: Line 616:
 
With 69,000 house fires in 2001, the performance of insulation in a fire affects loss of property and life. There are 3 main fire performance possibilities:
 
With 69,000 house fires in 2001, the performance of insulation in a fire affects loss of property and life. There are 3 main fire performance possibilities:
  
* Fireproof materials such as fibreglass and mineral wool act as a fire barrier, if they remain in position.
+
*Fireproof materials such as fibreglass and mineral wool act as a fire barrier, if they remain in position.
* Fire retardant materials burn away when flames reach them, but don't spread the fire further. They don't act as fire barriers.
+
*Fire retardant materials burn away when flames reach them, but don't spread the fire further. They don't act as fire barriers.
* Flammable materials such as untreated cardboard can ignite and spread fire. These products should generally be treated before use with a fire retardant, although there are examples where method of use provides another means to prevent spread of fire (eg plastered strawbale construction).
+
*Flammable materials such as untreated cardboard can ignite and spread fire. These products should generally be treated before use with a fire retardant, although there are examples where method of use provides another means to prevent spread of fire (eg plastered strawbale construction).
* Some materials produce toxic smoke in a fire, eg polystyrene
+
*Some materials produce toxic smoke in a fire, eg polystyrene
  
 
Cladding applied for external wall insulation has been implicated in some major fires including Grenfell Tower (June 2017).
 
Cladding applied for external wall insulation has been implicated in some major fires including Grenfell Tower (June 2017).
  
 
==See Also==
 
==See Also==
* [[Heat loss]]
 
* [http://www.livinginpaper.com/tests.htm Borax Fire Retardant]
 
* [http://www.lafargeplasterboard.co.uk/products/concepts/thermal1.htm Thermalcheck insulated plasterboard]
 
* [[Spray-on Roof Insulation]]
 
* [[Papercrete]]
 
* [[Expanding foam]]
 
* [http://groups.google.com/group/uk.d-i-y/browse_frm/thread/fb3a691eb58d730e?hl=en# Insulating a pool]
 
* [[Special:Allpages|Wiki Contents]]
 
* [[Special:Categories|Wiki Subject Categories]]
 
* [http://www.bre.co.uk/filelibrary/BR_443_(2006_Edition).pdf BR]
 
* [http://en.wikipedia.org/wiki/R-value_(insulation) R values of building materials, wikipedia]
 
  
 +
*[[Heat loss]]
 +
*[http://www.livinginpaper.com/tests.htm Borax Fire Retardant]
 +
*[http://www.lafargeplasterboard.co.uk/products/concepts/thermal1.htm Thermalcheck insulated plasterboard]
 +
*[[Spray-on Roof Insulation]]
 +
*[[Papercrete]]
 +
*[[Expanding foam]]
 +
*[http://groups.google.com/group/uk.d-i-y/browse_frm/thread/fb3a691eb58d730e?hl=en# Insulating a pool]
 +
*[[Special:Allpages|Wiki Contents]]
 +
*[[Special:Categories|Wiki Subject Categories]]
 +
*[http://www.bre.co.uk/filelibrary/BR_443_(2006_Edition).pdf BR]
 +
*[http://en.wikipedia.org/wiki/R-value_(insulation) R values of building materials, wikipedia]
  
 
[[Category:Basics]]
 
[[Category:Basics]]

Revision as of 15:37, 11 October 2018

Insulation reduces heat transfer, thus

  • Reduces heat loss in winter, saving on heating costs and improving comfort
  • Reduces rate of heat gain in summer, saving on ac costs.
  • Prevents freezing of pipes
  • Reduces run cost of hot water systems


Main DIY Applications

  • Wall cavity insulation (for either original wall cavities or a retrofitted cavity behind plasterboard)
  • Solid wall insulation (fitted to wall surfaces)
  • Loft insulation
  • Pipe insulation to prevent freezing or heat loss
  • HW cylinder insulation
  • Underfloor insulation

Forms of Insulation

Still air is a good insulator, and is the basis of more or less all insulation products currently used in housing. One way or another, each insulation product traps air, and its the air that does the job.

This means that if 6" of insulation is compressed to 4", it has the insulation value of 4" of material. In practice the change in size of the trapped air bubbles means that the value is affected slightly less than this.

If insulation gets waterlogged, its insulation goes down greatly.


Cavities

Cavity walls insulate much better than solid (non-cavity) walls, and are an early example of domestic trapped air insulation. Walls with no cavity can have a trapped air cavity attached by fitting battens and plasterboard - but there are better options now.

Large cavities allow some air movement, hence foamy and woolly insulation products give better insulation than a cavity alone.

Old cavity walls are also often open cavities, and in some cases end up with wind howling through them, much reducing their insulating effect.

Battens and other barriers to air movement improve an empty cavity's insulation a little, but nowadays denser insulation products are available that provide much better insulation value, and are well worth using.

Sheet or slab

Sheet or slab insulation is the most dense and effective type of insulation, and is used where insulation value per space needs to be maximised. This primarily means for roofs and solid insulation for walls.

Tough rigid sheets are used under floors, where walkability is required. Polystyrene also gets used in this situation, but tends to sag over time from foot traffic.


Roll

Roll insulation is far quicker to fit than sheet, and is mainly used for loft insulation. It is also used in wall cavities when its lesser insulation value is sufficient in the given space.

Loose fill

Loose fill is ideal for odd shaped or inaccessible spaces where the insulation will stay in place due to gravity alone. The biggest use for loose fill is for filling old cavity walls.


Insulation that doesn't insulate

Insulation is mainly used to insulate, but not always. Insulation material is often fitted into interior stud walls to damp sound transmission. Fibreglass & rockwool are the favourites, they're cheap, fireproof, readily available and acoustically absorbent to some extent.

Insulation materials

Expanded Polystyrene

now we know what polystyrene is shipped in

Low cost insulation available in

  • slab form
  • as small beads for loose fill & beanbags
  • shredded, cheaper than bead but less able to shed water
  • larger chunks for packaging

Mainly used for:

  • Roof insulation
  • Wall insulation
  • Floor insulation

Polystyrene is flammable, and produces toxic smoke on burning. This problem is made worse when painted with oil based paints.

Sometimes used for cavity wall insulation

  • Like any retrofit cavity insulation, it can saturate with water and cause damp problems
  • Beads are generally glued as they're injected, but in many cases the glue is omitted, and beads then pour out of any hole made in the wall
  • No longer the favourite cavity filler

Polystyrene in wall cavities is relatively well protected from fire, and is not considered a fire safety issue. However if PVC electrical cable is fitted in the wall cavity, as is occasionally done, polystyrene cavity insulation in contact with it causes the cable to leach plasticiser and become unsafe.

Sheet polystyrene is readily cut with any sort of knife, even a breadknife.


Ceiling tiles

Insulating decorative ceiling tiles

  • Dangerous in a fire
  • Spreads fire rapidly
  • Generates thick toxic smoke when burnt
  • Gloss painting them makes them even worse for flammability
  • Ugly
  • Best removed on safety grounds


Polystyrene veneer

A thin crack covering layer on walls a few mm thick

  • Primarily used to stop condensation, and sometimes cover bad cracking
  • Dents very readily
  • Grim news in a fire
  • Best removed on safety grounds

Fibreglass

Fibreglass insulation 5662-8.jpg
  • Comes in roll form, as loose fill and as semi-rigid batts
  • Lasts the life of the building no matter what life throws at it.
  • Waterproof
  • Insectproof
  • Verminproof
  • Fireproof
  • Springs back to shape if squashed
  • Lightweight
  • Loosefill fibreglass can be blown about in a draughty loft
  • Produces prodigious loose glass fibres
  • Tiny spiky glass fibres cause splinters
  • Concerns about its safety are occasionally expressed on the basis that it releases miniature sharp spikey non-dissolving airborne fibres, somewhat like known carcinogenic forms of asbestos. Fibreglass gradually dissolves in the lung, so doesn't pose the same risk
  • Dust mask should be used during handling
  • Gloves are also recommended to reduce splinters
  • Compressing a layer to improve insulation should be avoided. Squashing 6" down to 4" gives you about the insulation value of 4" of fibreglass, and the pressure can damage plasterboard.
  • Much used for loft insulation
  • Not a great choice in a windy position, wind can blow through it

Rockwool

A mineral fibre very similar to glass fibre, but denser, so much less airborne fibre.

  • Popularly used for loft insulation & internal stud walls
  • Comes in roll form, as loose fill and as semi-rigid batts

Polyisocyanurate

Celotex 4644-4.jpg
  • Rigid foamed boards
  • High R value per thickness
  • Good choice for lining walls
  • Kingspan & Celotex are the leading manufacturers
  • Seconds with minor defects are cheaper
  • Survives temperatures upto 400C

Cellulose

Cellulose insulation 1626-3.jpg
  • Low cost
  • Loose fill
  • Used in cavities
  • Plant fibre
  • Made from ground newspaper
  • Better performance than fibreglass
  • Slumps a bit over time, so not suitable for wall cavities
  • wikipedia
  • Appliable wet or dry - dry is more common for diy

Wet sprayed cellulose insulation:

  • Sticks itself in position
  • Same insulation value as loose fill
  • Doesn't slump
  • Must dry out before being boarded over

Fibreboard

Fibreboard

Used under timber floors

  • thermal insulation
  • sound absorbing
  • slight springiness
  • 3mm & 6mm common
  • breaks easily

Neoprene pipe insulation

Neoprene pipe insulation 5662-4.jpg
  • Foam-like tube pre-slit down one side
  • very easy to apply
  • Tape the slit shut or its much less effective
  • Corners in pipes are dealt with by cutting the 2 lengths of neoprene at 45 degrees
  • Tape the end gaps between lengths of insulation, and any other gaps or joints such as at corners

Felt

Felt pipe insulation 5665-3.jpg

Felt strip is used as pipe lagging

  • Its wound around the pipe(s) and secured with tape or a cable tie (don't squash the felt much)
  • Brown, hairy and untidy
  • Best used for pipes out of sight
  • Good for insulating grouped pipes, where foam jackets don't fit
  • Can be used for pretty much any shape and size of pipework
  • Foam tube is much quicker for insulating single pipes


PVC Cladding

  • Mainly used on gable wall ends
  • Keeps rain off the wall as well as insulating
  • Can make a messy wall look ok too, but not the world's favourite finish
  • Sometimes seen used internally, but tends to become hard to clean over time due to surface roughening, and not a popular finish even when new.


Timber cladding

  • Timber cladding is used as an interior and exterior finish
  • Provides a small amount of insulation
  • Several timber designs available
  • If fitting it anew, sheet insulation can go under the cladding


Insulating render mixes

Cement mixes containing polystyrene beads, leca or vermiculite

  • Fireproof
  • Paint to prevent water ingress and freeze/thaw damage
  • You can't have it all, to get fair insulation value the mix needs to be high in insulation beads, making it much weaker than concrete


Shredded Paper

  • Sometimes used as loose fill loft insulation
  • Waste paper is treated with fire retardant and chopped or shredded.
  • Recycled
  • Not damp tolerant


Cardboard

Cardboard 1in 4473-3.jpg
  • Very low cost insulation material
  • Rapid return on investment
  • Fitting used cardboard results in zero extra manufacturing energy use.
  • Cardboard wall insulation is popular in the US, but seems to have had little takeup here in the UK.
  • Its flammability can be resolved by painting it with a mixture of borax & boric acid.
  • Its damp susceptible, and can support mould if damp
  • Should not be used in situations where damp may occur.
  • Available free


Papercrete

Papercrete samples

A relatively novel building product, low density papercrete has good insulation properties and is made mostly out of waste paper and cement, with a number of possible additions including expanded polystyrene and fire retardants.

It can be cast into blocks, applied by tyrolean sprayer or poured into formwork.

Its not on general sale, its diy only. It requires lots of paper and a paddle mixer. It has a good track record so far, but is not BR approved for new builds.

Sheep's Wool

Sometimes used instead of fibreglass or rockwool.

  • Non-irritant, no protective clothes required.
  • Costs more than fibreglass & rockwool
  • Cheap if you or a nearby sheep farmer has wool they can't sell, unwashed wool is not allowed to be used
  • Insulation value low compared with PIR
  • This can result in excessive depth requirements in new builds, affecting ceiling height etc
  • Life 50+ years
  • Biodegradable
  • Chars, but doesn't spread fire
  • Treated against insects

Straw

Straw has long been used as insulation, and is another low cost option.

  • Susceptible to damp & mould, but less so than cardboard
  • Nest material for birds
  • Can contain unhatched insect eggs
  • Flammable, which can be resolved by plastering over the straw to deny the admittance of air for combustion.
  • Low cost
  • Used to be available in slab form, this is occasionally seen in use.
  • Insulation value per inch isn't great, works best where it can be applied thickly
  • Insurers may require MICC cabling in straw bale house construction


Clay beads

LECA expanded clay beads are occasionally used as house insulation.

  • Non-flammable
  • Unaffected by damp
  • Used as loose fill, mainly under floors


Vermiculite

Similar to expanded clay beads


Bubble wrap

Bubblewrap

Only rarely used in houses, wrapped round water tanks or used as an insulating window blind.

  • Degraded by UV light over time.
  • Flammable
  • Used as greenhouse secondary glazing
  • May last ok in dark places eg lofts & cupboards.


Foamed Concrete

  • Lightweight concrete blocks have insulation value
  • Insulation is one of the reasons for their use as the interior leaf of exterior walls
  • They don't survive outdoors unless rendered.
  • The light weight makes construction quicker

Aerogel

  • Aerogel is a very low density glass/air gel rated at 0.013 W/mK
  • High temperature resistance
  • Its steep price restricts it to applications where high insulation value per size & high temperature rating are necessary. This does not include house insulation.
  • Sold by Spacetherm.

Bottles

Bottles were historically used as floor slab insulation. A layer of bottles was laid before pouring the concrete, resulting in a degree of insulation plus reduced concrete use. The bottle shape produces lots of miniature arches in the concrete, which are a near ideal shape for loadbearing. For effective insulation there are now far better products.

Bottle walls and windows are used in alternative building, and create a pretty effect indoors, especially when mixed bottle colours are used. Bottle windows are quite usable for summerhouses etc. The bottles are used more or less like bricks, with thick cement mortar between them. The mortar provides most of the structural strength.

Bottles can be used for outbuilding floors where the budget is extremely tight, but insulation not needed. They displace some of the concrete.

When cement meets glass, ideally flyash or similar pozzolan can be added to the concrete mix to prevent the slight risk of ASR (alkaline silica reaction) causing cracking.

Issues:

  • A whole lot of bottles needed
  • Bottles can be vandalised, but in practice such buildings are normally well appreciated and not vandalised
  • In principle, differential thermal expansion and ASR can both crack bottle walls, in practice they work ok though


Expanding foam

Expanding foam & tape tube extension 4661-4.jpg


Underlay

Underlay 4514-3.jpg

Carpet underlays aren't used primarily for their limited insulation value. However on an uninsulated floor they do reduce heat loss to a degree, and that heat's worth money.

Perhaps some time someone will calculate what the payback is.


Cork

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  • Formerly used for insulation, but not much
  • Prone to rot & coming unstuck over time
  • The main use is for floorcovering

Asbestos

  • An obsolete insulator with safety problems
  • Sometimes needs removing for safety, but more often not
  • See Asbestos

Multifoil

Multilayered bubblewrap & foil type products are moderate insulators with debated insulation claims.

Unsatisfactory Insulation Materials

Carpet

  • Too thin to give much insulation
  • Flammable
  • Reduces draughts

Polystyrene ceiling tiles & wallpaper

  • Too thin to give much benefit
  • Very flammable, spreads fire & produces toxic smoke
  • Dents very easily

Sand

  • Traps air but is thermally conductive

Bubblewrap

  • Degrades quickly from UV exposure

Spray-on Roof Insulation

  • Traps water, prone to causing rot
  • Makes the roofcovering non-reusable


Free insulation options

  • Cardboard sheet
  • Waste polystyrene
  • Straw
  • Bubblewrap for water tanks & cylinders
  • Scrap clothing as pipe insulation


Applications

The more popular choices for each job

Loft

Deep insulation is usually fine in a loft, so the ideal properties are low cost per insulation value, and easily laid roll insulation. The 2 main candidates are

  • Rockwool
  • Fibreglass

Less often used:

  • Shredded or chopped fire retardant treated paper
  • Sheep's wool (available in batts as Thermafleece or rolls from www.BlackMountainInsulation.com)

Where insulation exceeds the depth of the joists and no floor is fitted, best practice is to fit the insulation in 2 layers, with the 2nd layer at 90 degrees to the first. This minimises any gaps and helps ensure the joists are completely covered too.

Where a floor is to be fitted, don't fit excess depth of insulation and squash it down. Any benefit of the extra depth is lost, and the ceiling may be bent or cracked by the excess pressure, or even come down.

When a floor will be fitted and its desired to use more insulation than the current depth of the joists, there are 2 options.

  1. The best is to add more timber along the top of the existing joists to deepen them, gluing and screwing it in place. This provides space and greatly [& stiffens the floor stucture].
  2. The simpler option is to insulate the existing depth, fit the floor, then lay out more roll insulation on top of the floor. This can be rolled back or just left in situ when boxes are placed there.
  3. Fit little supports for the floor, so it sits higher than the joists. Can be done with pieces of timber or little stands can be bought for the job.

Roof

The choice of roof insulation is mostly determined by depth. Lower cost insulators need more depth for BR compliance.

  • Polystyrene sheet - cheap
  • Polyisocyanurate - where depth of insulation needs to be minimised, not cheap
  • Sheep's wool - requires a whole lot of depth to meet BR


Cavity Wall Insulation

Fitted to existing original wall cavities:

  • Rockwool
  • Fibreglass
  • Polystyrene bead

Fitted to retrofitted cavities:

  • Polystyrene slab
  • Fibreglass
  • Rockwool batts
  • Polyisocyanurate


Solid Insulation for Walls

Fitted to the surface of solid walls (and occasionally to cavity walls) to increase insulation level further.

  • Polyisocyanurate (PIR)
  • Polystyrene foam backed plasterboard sheets may also be used, but don't provide very good insulation per thickness.
  • Cheap roll insulation may be used, eg rockwool, if battens are fitted and plasterboarded. However sheet PIR without studs gives much better insulation.
  • Hard surfaced insulating sheets. These have an extremely thin reinforced cement surface, so almost all their depth is insulation, but they're expensive


Tanks & Cylinders

The standard options for hot water cylinder insulation are:

  • jacket retrofitted - an improvement
  • foam coated cylinder - much better

Its also possible to create a container around the cylinder and fill the gap with insulation. In a typical airing cupboard this only requires hardboard across the front, and the space may be filled with any type of standard building insulation, or simply with free garbage of any insulating type, such as parcel packaging, cardboard & bubblewrap.


Pipes

Neoprene foam tube is most common. Its very quick & easy to apply.

Felt strip is also used. Its slower to apply and looks lousy, but can be used for pretty much any shape and size of pipework.

If you're penniless, a scrap clothing wrap is perfectly effective. Avoid leaving any gaps and tape it in place well. Use a tape that won't fall off, or string or cable ties.

R & U Values

  • R is a measure of resistance to heat flow, ie insulation
  • U is a measure of heat conductance
  • R value = 1/ U value

U is measured in watts per square metre per centigrade (W / m^2 C)

  • The temperature figure is the temperature difference between the 2 sides of the insulation rather than ambient temperature
  • W/m^2 k is more widely quoted, but has exactly the same value as above
  • Beware of American R figures being quoted in completely different units

To determine a figure for multiple elements in series (which is how most walls are composed), just add up the R values of each element.


Insulation Values

The following values are a good guide, please check your chosen insulation product for its precise value.

Masonry

  • Brick: R = 0.03 per 25mm
  • Single brick (4") R = 0.12
  • Solid brick 9" 0.44
  • Concrete 0.015 per 25mm
  • Limestone R = 0.017 per 25mm
  • Cavity wall: 0.53
  • 4" AAC wall: 0.78
  • Lime plaster R = .05 per 25mm
  • Unventilated Cavity R = 0.18
  • Outside air bounday layer = .03
  • Inside air boundary layer = .12
  • Aerated cement block

Wood

  • Softwood typically 0.25 per 25mm
  • Timber cladding typ 0.44 for 25mm

Insulation materials

  • Marmox R= 0.75 per 25mm
  • Kingspan R = 1.08 per 25mm
  • Celotex R= 1.31 per 25mm
  • Thermafleece (treated sheep's wool) R = 0.65 per 25mm
  • Expanded polystyrene slab 0.63 - 0.88 (loose fill value is lower)
  • Fibreglass loosefill R = 0.45 per 25mm
  • Fibreglass batt 0.55-0.76 per 25mm
  • Straw bale 0.26 per 25mm
  • Vermiculite loose fill 0.4 per 25mm
  • Pearlite 0.48 per 25mm
  • Rockwool loosefill 0.44-0.65 per 25mm
  • Rockwool batts 0.52-0.68 per 25mm
  • Cellulose 0.52-0.67 per 25mm (for both dry & wet sprayed)
  • Polyurethane panel 0.97 - 1.2 per 25mm
  • Polyurethane expanding foam: same
  • Foil faced polyisocyanurate panel 0.97 - 1.2 per 25mm
  • Cotton batt:
  • Aerogel 1.76 per 25mm
  • Vacuum 5.28 per 25mm
  • Cardboard 0.52 per 25mm
  • Wood chips and similar products R=0.18 per 25mm

Note that some insulation types have R values that deteriorate a bit over time due to compaction or loss of their insulating gas component. This is primarily true for polyisocyanurate(PIR), gas filled double glazing and vacuum panels.


Windows

  • Window, single glazed: 0.18
  • Window, double glazed: 0.35
    • can be improved to over 0.5 with noble gas fill & glass coatings
  • Note thicker glass makes no noticeable difference to R value
  • Window, triple glazed: 0.52
  • Thermal lined close fitting curtains & pelmet: 0.3
  • Roller blind: 0.18

Other materials:

  • Earth R=0.58
  • Weatherboard wall: 0.55
  • 12" mud wall 0.27
  • Chipboard R=0.17 per 18mm
  • Asbestos cement board 0.018 per 8mm


For more info see Wikipedia

Cold Bridging

A common issue with insulation is cold bridging. This is where there are patches that aren't insulted like the rest. Causes are:

  • Gaps left in the insulation
  • Places where insulation changes from interior to exterior
  • Places where existing building materials prevent fitting of insulation. Some examples are:
    • insulation sheet fitted into a timber frame, leaving the frame itself uninsulated
    • Cavity wall insulation unable to insulate around windows, due to lintel above, and existing masonry on all sides
    • Plasterboarded battens with insulation fitted between battens

Cold bridging also has the potential to cause a damp problem. Where previously either no condensation occurred, or it occurred over a large area and evaporated fairly quickly without incident, after insulation condensation can concentrate onto relatively small cold bridges and cause mould or fabric damage. This isn't normally a problem, but can be.


Wind and insulation values

Any gaps that admit wind allow heat loss to simply bypass the insulation in that area. Thus good insulation requires plugging any gaps. Depending on the situation this can be done with loosefill insulation, injected expanding foam, pressed in foam strip, or for opening doors and windows, brush strip or foam strip.

Wind can blow through some insulation types, eg fibreglass loft roll, much reducing their insulation value. These types are not well suited to use in windy positions.


Testing insulation values

Some unpopular insulating materials don't have a known insulation value, they've not been tested. If you want to use nut shells for example, you can if you wish set up an experiment to determine their insulation value.

A stack of the following may be used, in this order:

  • heat source (eg spotlight)
  • top metal plate to spread heat out evenly
  • an insulation material of known value (R1)
  • insulation material under test (R2)
  • bottom metal plate to spread heat out evenly

Thermometers or thermocouples are added at the 3 insulation boundaries, at

  • top metal plate
  • bottom metal plate
  • the interface between the 2 insulation layers

Thick high insulation value material is added around the 4 sides of the stack. The stack bottom is left uninsulated.

The stack is left with the heat source on for hours to stabilise, then the 3 temperatures are read.

The insulation value of the unknown layer is determined from the ratio of thermal resistance (insulation) values. Where the resistances are R1 and R2:

middle interface temp - bottom plate temp = (top plate temp - bottom plate temp) x R2/(R1+R2)

Most accurate results are obtained when the insulation values of the 2 layers are in the same ballpark, and top plate temp is high. For accuracy, avoid using results where the middle interface temp is close to top or bottom plate temp, or the top plate temp is low.

Self testing is only sufficient for applications where BR approval is not required. To obtain BCO approval with non-standard materials requires the test results and building insulation design to be signed off by an engineer. Other aspects of insulation also need to be considered in this

  • ability to survive damp
  • rotproofness
  • fire performance
  • longevity
  • insectproofness
  • and rarely toxicity


Fire

With 69,000 house fires in 2001, the performance of insulation in a fire affects loss of property and life. There are 3 main fire performance possibilities:

  • Fireproof materials such as fibreglass and mineral wool act as a fire barrier, if they remain in position.
  • Fire retardant materials burn away when flames reach them, but don't spread the fire further. They don't act as fire barriers.
  • Flammable materials such as untreated cardboard can ignite and spread fire. These products should generally be treated before use with a fire retardant, although there are examples where method of use provides another means to prevent spread of fire (eg plastered strawbale construction).
  • Some materials produce toxic smoke in a fire, eg polystyrene

Cladding applied for external wall insulation has been implicated in some major fires including Grenfell Tower (June 2017).

See Also