Difference between revisions of "Shelves"
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Revision as of 16:28, 7 April 2012
As the stereotypical subject of the occasional DIYer, shelving can not be overlooked on a DIY wiki.
Shelving is divided into 3 main sections: Materials, Fixing and Sag.
Also known as particleboard
- 12mm: cheap, liable to sag
- 18mm: stronger than 12mm chip, so less sag prone
- Flooring grade: grades used for flooring are high density chip, which is a stronger type of chipboard than the usual 4x8 sheets, for the same thickness.
eg formica, melamine, imitation woods
- Most popular choice
- Available in white & imitation wood finishes, and occasionally in black & some other plain colours.
- Prone to sag over time
- Edge and corners of veneer prone to lift or break off in time
- Not likely to last a lifetime.
- Where a cut edge will be visible, matching edge banding is applied using an iron.
Medium Density Fibreboard (MDF)
Smoother finish than "raw" chipboard especially on cut edges.
MDF has little strength for a given weight so spans have to be short and sections of the material have to be thick to reduce sagging, or edges can be reinforced with thicker wood to give rigidity.
The fine dust produced by cutting and especially sanding this material may be irritating to the lungs.
MDF is available in veneered finishes.
MDF is quite vulnerable to water damage, placing cups on it with the odd drip is enough to ruin the surface over time.
e.g. pine, oak, etc.
- Good looking, though not everyone likes wood
- Good wear characteristics
- To avoid stains it needs finishing with varnish, wax, oil or paint.
- Wood plank is prone to cupping
- Shelving made from alternately oriented narrow strips glued together more or less eliminates the risk of cupping. Sold as pineboard or timberboard, and very stable compared to plank wood.
Pineboard or timberboard is made of strips of timber glued together with alternating grain. This is what's usually referred to as simply 'pine.' Good looks, if you like pine. Fairly stable, but not very water tolerant.
Like planks, strength and stability is very different in the 2 directions. When supported on brackets, ensure the wood grain runs along the shelf, not from front to back. When supported by rails under both front and back, grain running from front to back is the stronger configuration.
Similar performance to timberboard, but a non-striped veneered finish.
A strong and stable shelving material, but more cost than the above options.
Birch ply with many laminations of equal thickness is better suited for shelves where the edges are likely to be visible. It is more expensive than normal construction-grade ply e.g. £33 for 2400 * 1200 * 18mm compared to about £25 for the same size fair-faced WBP ply.
If not painted, ply may have the striped edge stained darker to make the striping less noticeable.
Sheet plastic makes a weak shelving material, requiring support on all 4 sides, and is not recommended due to poor strength to cost ratio and uninspired looks. However it does work and is unaffected by damp.
Lightweight veneered interior doors make effective large shelves or desktops. The corrugated cardboard core gives them a relatively high strength per weight.
However they are large, and are not simple to cut down to lesser shelf depth (door width) without causing significant damage or loss of strength.
Metal brackets are by far the most common. They are available as low cost London brackets, medium price styled brackets, or higher cost very heavy duty brackets.
Wood brackets can be made in various patterns from material to hand. Wood brackets tend to be found as either basic brackets where appearance doesn't matter, or fancy brackets where wood permits intricate carving.
Wood brackets are mostly free to make, and their wide open scope for styling makes them an opportunity to add visible character to a room.
Slotted or holed uprights are popular. Wood or metal brackets fit to these, allowing fairly easy moving of shelf heights, and permitting more layers of shelves to be added or removed at will.
Shelves may be hung on vertical wires. The steel wires need to be tensioned to hold the shelves in place. Gives a light high tech look. Popular with glass shelves.
Single die LEDs can be added to make the glass edges glow.
These use concealed metal brackets that fit inside the (thick) shelf material. The shelf has no visible support, giving a neat clean appearance. Good for light loads.
Uprights front and back is an alternative to the more common L shaped brackets. These may be wood or steel. Once uprights are added, the shelves effectively become a shelving unit. Alternatively, uprights may be used at the front only, with small fixings to the wall at the back.
Another alternative to brackets is to support a shelf on 3 sides with a wood frame. This works for shallow shelves of limited width, but is not successful with larger shelves as it does not support the shelf front.
Supporting the shelf on all 4 sides works well for small & medium shelf widths, but the under-front support can be intrusive.
Or the front support can be used to hide the shelf material entirely, by sitting the shelf in a long cutout in the front support. This is an effective way to give chipboard shelves the face of real wood. CLS timber can be used which is already planed & rounded on all 4 edges, making the job relatively easy, and the finish appealing.
______ __________________________ | |__________________________| | | |________| Chipboard shelf supported by timber front
The wider the span between supports, the less load the shelf will support, and the more likely it is to sag.
A strip of wood under the back edge of the shelf provides support for a 3rd side of the wood, increasing overall strength and reducing sag. With brackets this will usually be in several pieces to fit between the brackets.
A strip along the front can be used with brackets just as well as with frame support. If not supported at its ends it should be fixed to the shelf securely, as sagging will try to make the two part company with some force. Glue plus fat screws gives maximum fixing strength.
Size & Sag
A deflection of 1/32 inch per foot or more is noticeable to the eye.
A loaded bookshelf may support in the region of 10kg per foot of length. Loads will be higher if the books are packed in densely, eg with books stacked.
Wood and chipboard typically sag 50% more than initial sag over time.
link to a more accurate calculator
A yardstick makes an unusual shelf, suitable for displaying cards etc.
A pretty shelf may be made from 4mm pine 4" deep supported by small decorative brackets every 18". Such shelves are obviously very lightweight and should only be used for light objects. Books would be too heavy for a 4mm shelf.
These nicknack shelves can go where there is not enough space to warrant a larger shelf, and are quickly made from leftovers.
Such shelves may also be used for storage of the smallest and lightest of diy supplies.
Cardboard strip is folded like so to give a stiff triangular section strip:
________ ________ _____ / ______ | \ / OR \ | \ / \ | \/ \ | \|
Kids can use this to add an extra shelf among existing shelves. Black oil based paint makes the corrugations less noticeable.