Making strong fixings to internal walls

A number of different types of internal wall will be found; masonry plaster, stud wall (either plasterboard or lathe and plaster), plasterboard dry lining - see our page which explains these different types of wall. Which type of wall you have, will affect how strong fixings (i.e. for brackets) can be made to them, below we give suggestions for making strong fixings to masonry plaster, stud walling, plasterboard dry lining walls.

Masonry plaster walls:

Strong fixings can be easily made on most masonry walls just by using screws and wall plugs - for extremely heavy loads wall bolts can be used.

Plaster alone is not strong enough to hold wall plugs, so the holes (and plugs, screws) need to be long enough to go through the plaster into the brick or block work.

Another weak point may be the mortar joints between the bricks/blocks, especially where lime mortar has been used - it is best to locate the fixing so that the fixing holes go into actual brick/block rather than the mortar joints.

Some clay bricks (mainly old ones) and true concrete blocks contain hard pieces (flints etc) which can cause a drill bit to run off line - this can result in the bracket holes not lining up or the shelf not being level. To overcome this, an option is to fix a batten to the surface of the plaster and then screw shorter fixings for the brackets into this batten.

Some blocks (such as modern high insulation types) are extremely soft, always drill these carefully to avoid over-enlarging the hole and use the special wall plugs.

Stud walling (both lathe and plaster and plasterboard).

Do not fix shelving just to the plasterboard (or lathe and plaster), strong fixings can only be achieved when fixings are screwed directly into the vertical timbers (the studs).

The studs are normally set at equal distances apart - on older stud walls they are usually no greater than 405mm (16 inches) apart, while in more modern stud walls, the maximum spacing is about 600mm (24 inches).

To find the position of the studs behind plasterboard, lightly knock on the wall while moving sideways - the studs should sound solid while the spaces between should sound hollow.

It is not so easy to locate the studs holding up lathe and plaster finishes as there is no discernible difference in the sound of a knock. When all else fails, the last resort is to draw a horizontal line where the shelf is required and to drill small holes along the line about 25mm (1 inch) apart until solid timber (i.e. a stud) is located. Once the first stud has been located, measure along the line in multiples of 405mm (16 inches) and drill through to confirm the location of the next stud - if further studs cannot be located in this way, the only option is to drill another series of small holes until a stud is found.

Lathe and plaster walls may crack when a bracket is tightened down onto the surface as the lathes are compressed. Drill clearance holes through the lathe and plaster so that these are not subjected to excessive sideways pressure as the screw is fitted.

Dry Lining walls.

Dry lining is possibly the most difficult type of wall to get a strong fixing as the surface plasterboard is only supported by 'blobs' of adhesive. Any attempt to pull down a bracket onto the unsupported surface will cause the lasterboard to deform.

A practical solution is to:

• Identify where the fixings will go.
• Cut out the plasterboard at these points.
• Make and fit spacers which can be tightened down onto the blockwork behind the plasterboard. The cut-outs and spacers can be small so that the bracket or batten cover them, or large - although 'large' is less fiddley, it is harder to blend it in with the rest of the wall.
  The bracket can be fixed with screws through the spacer into plugs in the blockwork, or the spacer can be screwed to the blockwork and then shorter screws used to fix the bracket.