With hollow surfaces strength of the fixing is generally less than for a solid structure. It is always easy with hollow surfaces to locate and fix into one of the support members. It may not always possible. It is sometimes necessary to secure onto the covering, be it plasterboard, hardboard or whatever.

When you are drilling relatively thin and soft materials, it is not necessary to use hammer action if you use a power drill. Before drilling into any void, check for concealed pipes and electric wiring.

Here we present different kinds of fixing.

Rubber-sleeved fixing with captured insert :

The screw has to be tightened into the rubber sleeve inserted through the wallboard. Then the sleeve gets compressed against the reverse side of wall. The screw can be removed or replaced depending on need. But the fixing will remain in place through the wall.

After drilling the required hole, insert the rubber sleeve through the covering. The sleeve has to be a fairly tight fit through the hole; then it does not rotate when the screw is tightened. Then the screw is inserted through the work piece and into a tapped insert, which is moulded into the back end of the sleeve.

The sleeve has a small rim, which stands proud of the outer surface. It allows the work piece to sit flat against the surface. The back of the work piece has to be relieved around the hole.

Various sizes of screws are available. The screws are supplied with the fitting. Longer screws of the appropriate diameter or thread can be used if the work piece is too thick for the screw supplied.

Plastic collapsible fixing :

This is very similar to the above fixing, but uses an ordinary wood screw. It can be used in the same manner as the above. But it tends to stand up less well to repeated screw removal or replacement, as the screw tends to cut a new thread each time it is inserted.

Plastic spread fixing:

It is an inexpensive fixing which is not reusable. Removal of the screw results in the fixing dropping down the cavity. Various sizes are available to suit various diameters of wood screw.

First drill a hole just large enough to take the head of the fixing. Use a normal wood screw of the appropriate length – which is at least equal to the thickness of the work piece plus the thickness of wallboard plus the length of the fixing. Insert it through the work piece and into the fixing by about 2 or 3 turns. Push the fixing through the hole in the wallboard. As the fixing is pushed through, the legs of the fixing get compressed and they spring out once the fixing is through the board. The work piece has to be pulled away from the front surface, so that the legs of the fixings bear on the reverse side of the wall when the screw is tightened.

Spring metal toggle fixing:

These fixings give a stronger anchor than the plastic types above, because they spread the load over a larger area on the reverse side of wallboard. The fixing consists of two spring-loaded metal arms with a thread tapped into the hinge pivot. The two arms are held against the screw as the fixing is inserted through the pre-drilled hole; then spring out to spread the load on the reverse side of the wallboard. The fixings cannot be reused. Removal of the screw results in the fixing dropping down the cavity.

Drill a hole just large enough to allow the toggle to be pushed through with its spring-loaded arms held together. Pass the fixing screw through the work piece into toggle. Push the toggle through the hole until the arms spring out, pull the work piece away from the front surface so that the arms bear against the reverse side of the wallboard, and tighten the screw.

Various sizes are available. The screws are supplied with the fitting. Longer screws of the appropriate diameter or thread can be used where the work piece is too thick for the screw supplied.

Gravity metal toggle fixing:

These fixings are similar to the spring type above, but the toggle is made in one piece which is passed through the hole and then drops down under gravity to be parallel to a vertical wallboard. These fixings can be used only when fixing to vertical surfaces. The fixings cannot be reused as removal of the screw results in the toggle dropping down the cavity.

Drill hole just big enough to allow the toggle to be passed through, when the toggle is parallel to the fixing screw. Pass the fixing screw through the work piece into toggle. Push the toggle through the hole until it turns within the cavity; pull the work piece away from the front surface, so that the toggles bear against the reverse side of the wallboard; and tighten the screw.

Various sizes are available. The screws are supplied with the fitting. Longer screws of the appropriate diameter or thread can be used if the work piece is too thick for the screw supplied.