WALL FIXINGS

There’s a huge variety of wall fixings available. Some are designed for solid walls, some for hollow walls.

Choosing the right one will ensure that whatever you’re fixing stays there.

Two things will decide which type of wall fixing you need: the first is the strength of fixing you require – book shelves, for instance, are going to need a much stronger fixing than a picture frame – and the second is the kind of wall you’re fixing to. Whether you’re fixing in solid walls (either plaster covered brick, stone, concrete, or some other kind of building block) or in hollow ones (plasterboard, lath and plaster, or wood panels fixed to a timber framework), screws are normally used. However, on their own, screws don’t grip in masonry, so you have to use some sort of plug

Fixings in solid walls

Drill a hole, insert a wall plug, and then drive the screw into that. As the screw penetrates, the plug expands and presses against the sides of the hole. So long as you don’t overtighten it (in which case the screw thread will destroy the plug) the screw will then be very firmly embedded indeed.

You must, though, ensure that the plug expands in solid masonry, rather than in the plaster coating. Or in any mortar joins.

Standard wall plugs Also made from plastic, these give a stronger fixing than strip plugs. Designs vary, but all have slits or opening jaws to increase the degree to which the plug can expand, as well as fins and barbs to increase grip. The other advantage of this sort of plug, is that, with most brands, one size of plug can take several sizes of screw, without reducing the fixing’s strength. —

Fibre plugs These are made from compressed fibre with a built-in pilot hole for the screw. They come in various sizes and lengths, and to get a good fixing both the hole and plug size must tally exactly with the size of screw. Refer to the manufacturer’s recommendations here.

Strip plastic plugs Similar to fibre plugs, these are sold in 300mm (12in) lengths so you can cut off just the amount you need. Again, you must match the size of plug and the hole to take it, with the size of screw, and to help you the plug sizes are colour coded. White is for screw gauges 4 and 6 and needs a hole drilled with a No 8 masonry bit; red is for gauges 6 and 8 and needs a No 10 bit; green is for gauges 8,10, and 12, and needs a No 12 bit; and blue is for gauges 10. 12, and 14, and needs a No 16 bit.

Breeze block plugs One thing ordinary plugs are not good at is gripping in soft or crumbling masonry, notably breeze block and aerated concrete block. Here a special plug is required. It consists of a central core surrounded by tough, flexible fins arranged in a sort of spiral. To use it, drill a hole a little larger than the central core, and hammer the plug in. The fins compress, then force themselves against the sides of the hole to hold the plug even if the masonry does give way.

Wooden pegging The solution to the problem of fixing into mortar joints- take a piece of wood, preferably hardwood, roughly 19mm (Jin) in diameter, taper one end, and then drive it into a 12mm (Jin) hole with a mallet. You can then screw into it in the same way as any other piece of timber.

Masonry nails Masonry nails are used like any other nail. They are just specially hardened, and designed to penetrate and hold in masonry. They come in sizes to suit most jobs – choose a length that will penetrate the wall by about 19mm (Jin) – and, in spite of their tendency to shatter if you don’t hit them squarely, they do offer a fast way to get a fixing. However, the result is not neat, so reserve them for rough constructional jobs, where looks are not important.

Rawlbolts The thing to use if you need a really heavy-duty fixing -for example, fixing a lean-to roof to the side of a house. Rawlbolts work in much the same way as a standard plug, but are made from metal, and come ready-fitted with a bolt. Various sizes are available, and you can choose between a number of types of head, including a threaded stud to take a nut, a hook, an eye, and a normal hexagonal bolt head.

Plugging compound For a relatively light fixing in crumbling walls, use a plugging compound; a fibrous material that you mix with water and pack into the hole using the tool provided. Once the hole is full, make a starting hole with the pointed end of the tool, and carefully drive in the screw. As the compound dries, it ‘cements’ the screw in place.

Fixings in hollow walls

Here, getting the screw to grip is even more of a problem than with a solid wall. After all, the screw has nothing to bite on but air. There are a number of ingenious solutions, but virtually all have a snag; remove the screw, and the fixing device is lost inside the cavity.

Petal anchors Made from plastic, these are twisted onto the end of the screw and pushed through the hole into the cavity beyond. As the screw is tightened, the anchor’s petals open out against the back of the plasterboard, or whatever, thus preventing both anchor and screw from pulling out. (

Expanding plugs Designs vary, but all work in the same sort of way. You push them into the hole, insert a screw – some have a built-in machine screw – and tighten up. The plug bulges out inside the cavity until it is too large to come back through the hole.

Gravity toggles The toggle is essentially a small metal hinged device fitted to the end of a machine screw (supplied). When pushed through the hole, it flops down inside the cavity, bridges the hole, and so allows the screw to be tightened. This bridging action is ideal for lath and plaster walls.

Spring toggles These use the same principle as gravity toggles. The difference is that two sprung metal wings are used to do the bridging job.

Screwing into the framework

The only way to make a really strong fixing in hollow walls is to screw directly into the wall’s internal timber framework. This consists of upright ‘studs’ spaced about 400mm apart, and horizontal ‘noggins’ put in mainly where there is a horizontal join between plasterboard sheets. The former offer the strongest support for a fixing.

To locate them, tap the wall until it sounds reasonably solid, then drill a series of tiny test holes until you strike wood. If the studs aren’t where you need them, span two with a stout piece of timber screwed in place on the surface, and make the fixing into that.

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