Wallplug
Plugs for solid masonry
Standard plug
The standard moulded plastic wallplug is by far the most popular option. These come with recommended hole and screw sizes, and are simple to use.
Different sizes are often colour coded, but different brands don't all follow the same colour code.
Fibre plugs
Fibre plugs are straight sided compacted fibre plugs.
Lipless plug
Plugs with no lip are good when using 2 moulded plugs in a hole.
Sticks
Long sticks are no longer common, but are still available. This allows you to cut a plug of any length. They come in plastic or fibre, about a foot long.
Sheet metal plugs
These are made from contorted thin sheet metal, and are fire resistant. In soft masonry they have a lower pullout rating than a plastic plug.
Metal expanding plug
These use 2 cast halves of metal than expand when a bolt is screwed in. Not suited to use with regular wood screws. These put high forces on the masonry, so should not be used near edges.
Plugs for hollow walls
Expanding plastic plug
The cheapest type of hollow wall plug, these look similar to regular plastic plugs, but expand behind the plasterboard when screwed into.
Universal plug
These are expanding plastic plugs that can be used with both solid and hollow walls.
Redidrive
Available in metal and plastic, these screw into the plasterboard.
Hammer in
2 sheet metal legs spread when screw inserted. No hole is drilled, they're just hammered into position, making work fast. Load rating so-so.
Spring & gravity toggle
Both types of toggle use a metal bar behind the plasterboard to take the load. Gives a fairly good load rating for static loads. With dynamic loads, such as coathooks, these tend to gradually eat through the plasterboard until they eventually fail.
Lightweight things
Expanding bolt
Better than hollow wall plugs
Hollow wall plug fixings are only ever as strong as the plasterboard. Where greater strength is necessary:
- fix through to solid masonry behind the plasterboard, if there is any
- fix to an upright or nogging on frame walls
- Replace the plasterboard with plywood, or fit ply to the surface
- Fix to floor instead
Misnomers
Rawlplug is a well known brand of wallplug. 'Raw plug' is often heard too.
Methods
The standard method is to drill the hole size recommended, blow dust from the hole, insert the plug full depth, and use a screw of the thickness recommended. Of course this isn't the only option.
Other screw sizes
Where grip is likely to be poor, a thicker than recommended screw can increase compression on the plug and thus grip.
A thinner than recommneded screw can be used to ease driving where the recommended size is too tight.
Reduced hole size
Soft masonry tends to produce a hoole bigger than the drill bit. A drill bit half a mm smaller helps keep things tight.
2 plugs
For a stronger fixing, a deep hole & 2 plugs are used. This is especially useful in soft masonry, and where the surface layer is weak, eg crumbly plaster.
Packing
Uneven or oversize holes will need packing to make them work. This is easiest done with matchsticks, but split wallplugs are also good.
Troubles
It just keeps turning
If a wallplug just turns instead of tightening, the following sometimes work:
- Blow dust out and reinsert plug
- Use a bigger plug that fits tighter
- Fill hole with filler, and when set re-drill
- Pack something round the plug before reinserting
- Hammer matchsticks into all available gaps. Matchsticks leave a lot of gaps so you need to pack every avaailable gap. Insert screw, remove it again and hammer more matchsticsk in. Now you'll get a good strong bite.
- Insert resin glue into hole, refit plug, let set.
- Other bulking glues can also be used, such as polyurethane. They aren't as strong.
- Put a quick set filler disc around the plug, reinsert the plug, let it set.
Hole oversize or misshapen
Either:
- Drill deeper and use 2 plugs to get a deep fixing.
- Blow all debris out of hole, fill with interior filler, try again tomorrow.
- Use resin, with or without plug
- Use a filler disc around the plug
Hole keeps crumbling
Blow all debris out of hole, fill with interior filler, try again tomorrow.
Some holes crumble
If some do some don't, Coat all holes inside and out with glue (eg pva) and fix when the glue is set. The pva reinforces the crumbly material.
Plug & screw pulls out
If the whole fixing pulls out after the screw is in, then the plug & screw are too small for the hole.
- Pack the plug
- Use a much thicker screw
- Use a thicker plug if it'll fit
- fill the hole and retry once set
- Use resin
Screw jams
Screw too thick for plug & hole. Use a thinner screw, or possibly a thinner plug or slightly increased hole size.
Hollow wall plug pulled out
That's life, plasterboard isn't very strong. Some hollow plugs grip more area of plasterboard than others, but if these aren't tough enough you'll need to fix to something stronger than plasterboard. That could be
- solid masonry behind a gap behind the plasterboard
- wood or metal frame
- sheet ply on the wall
- fix to the floor
- in extremis build a wood frame fixed to floor & ceiling, and fix to that.
- or use a free standing appliance instead
When plugs don't work
There are a couple of wall materials where plugs won't work no matter what. These include earth & straw walls. In these cases another fixing method altogether is needed, normally one where the load is supported by the floor instead of the wall.
In some cases using a timber frame fixed to floor and ceiling is about the only safe option. This is true for example of a large screen TV mounted to the wall.
Plug Material
Plastic is most popular and the cheapest. Plastics are vulnerable to heat, and in a fire all plastic plugged fixings can be exected to collapse. Plastics aren't affteced by water, making them good for outdoor use.
Nylon plugs are tougher than lower cost plastic, and support a greater load.
Metal plugs have much better fire resistance, but are vulnerable to rust outdoors. They give a weaker fixing than plastic in soft masonry, and a stronger fixing than plastic in high strength masonry.
Wood plugs have better fire resistance than plastic. They're vulnerable to rot if they get wet, so not good for outdoor use.
Fibre plugs are tougher than plastic
Wallplug substitutes
Commercial
Dowel
Ad hoc
Bit of wood split off. Hammer more slivers of wood into any gaps.
Matchsticks - hammer in & snap off. Pack them tight, screw in, remove screw and repack.
Rolled paper - not a great performer but can work.
Card - folded card works if packed well enough.
Bits of plastic - another poor performer but can work if packed tight enough, ie they need to be hammered in.
Alternatives
- Frame fixings - hammer-in screw & plug in one.
- Masonry screw - screw direct into masonry, no plug
- Masonry nail
- Plastic aerated concrete nail - hammers into aerated blocks
- Resin fixing - higher load rating than any plug type - fill hole with resin, let set, drill & screw
- Wedge - remove some mortar from between bricks,
- hammer in wooden wedge)
- In extremis, fix to floor or ceiling instead.
- Putties - various fillers, glues & putties can be used to fill a hole and screw into. Historic brands include Rawlplastic & Philplug. Good for uneven shaped holes.
Various other types of fixing may also be used instead.