What type of wall do I have, and what does it change?

Solid, studwork, dot-and-dab and lath and plaster look identical once painted, and every fixing, repair and improvement decision differs between them. What each build-up is, and what each one changes.

Difficulty: beginner
Time: 20 min
Read: 5 min

Short answer

British internal walls come in four common build-ups: solid masonry with plaster on it, timber or metal studwork with plasterboard on it, dry lining where plasterboard is dabbed onto masonry with a void behind, and lath and plaster. Establish which you have before you choose a fixing, a repair, a board, an insulation measure or a soundproofing measure — the correct answer is different in all four.

Almost every wall question people ask is really this question in disguise. Why did the plug spin out, why does the crack keep coming back, why can I hear next door, can I take this wall down, can I hang this here. None of them has one answer. They have four answers, and the wall decides which one applies. Two minutes of identification saves the afternoon.

The four common internal wall build-ups in cross-section

Step by step

Tap it, and listen for where the sound changes.Dead and dull everywhere means solid masonry. Hollow with dull lines at roughly 400 or 600mm centres means studwork. Hollow almost everywhere, with dull patches in an irregular grid, usually means dry lining dabbed onto masonry.
Use the age and position of the wall as evidence.External walls of a house are masonry, effectively always. Internal walls in a pre-1930s house are commonly lath and plaster or solid brick. Internal walls in a post-1960s house are commonly studwork. A house re-plastered since the 1980s often has dry lining over masonry that used to be wet plastered.
Drill a small test hole somewhere it will not matter and read the dust.White or pale grey chalky powder is plasterboard. Pink or red grit is brick. Fine mid-grey is dense block or concrete. Very pale grey that drills unnervingly fast is aerated block. Grey dust with coarse animal hair and timber splinters in it is lath and plaster.
Note how far the bit travels before it meets resistance.Twelve or thirteen millimetres and then a void is board on studs or on dabs. Twelve millimetres and then hard material forever is plasterboard skimmed or dabbed onto masonry. Resistance from a few millimetres in is wet plaster on masonry. Around 20 to 25mm of soft material with springy timber behind it is lath and plaster.
If it is hollow, find out whether the void is a stud bay or a dry-lining gap.This is the distinction people get wrong most often, and it changes the fixing entirely. Studs at a regular spacing with a continuous void between them is a partition. An irregular pattern of firm spots with masonry a short distance behind is dry lining.
Work out what the wall is doing structurally before you plan any alteration.A studwork wall is not automatically non-structural and a masonry wall is not automatically load-bearing. Anything involving removing a wall or forming an opening in one is a structural engineer's question, not a judgement made from tapping.
Write it on the wall, in pencil, where the skirting will hide it.Or photograph the room with the studs and dabs marked before you cover them. You will want this information again — for a shelf, a radiator, a TV bracket, a socket — and re-establishing it costs the same twenty minutes every time.

Tips

A wall can change build-up halfway along. A chimney breast is masonry, the alcoves either side of it are often studwork or dry lining, and a wall that was re-lined in one room may be original in the next.
Metal studs behave differently again — thin, springy steel C-sections, common in flats and conversions. A fridge magnet finds them in seconds and is the fastest single test there is.
Ceilings follow the same logic: plasterboard on joists in most post-war houses, lath and plaster in older ones, and occasionally plasterboard overboarded onto lath and plaster, which is why some ceilings are unexpectedly thick.

Common mistakes

Assuming an old house means solid walls throughout — Victorian and Edwardian internal partitions are routinely lath and plaster on timber studs. The fixing that holds beautifully in brick tears straight out of both the plaster and the laths.
Treating dry lining as a stud wall — Cavity fixings need a fixed span of board with room to open behind it. In dry lining the gap is small and irregular, so toggles jam or crush, and the correct answer is a long fixing that passes through the board into the masonry behind.
Deciding from a stud detector alone — Detectors read density changes. Foil-backed board, pipes, cables, dabs of adhesive and old repairs all read as studs. Confirm with a small hole before you commit to a load.

If it doesn't work

Wall sounds hollow but no regular stud spacing can be found

Cause: Dry lining on masonry rather than a partition — Fix: Drill a longer test hole. Hitting hard material 20 to 40mm behind the board confirms it, and the fixing should reach that material.

The drill goes in easily then stops dead

Cause: Board or thick plaster over masonry — Fix: Switch to a masonry bit and hammer action for the rest of the depth, and choose a plug long enough to sit entirely in the masonry rather than in the plaster.

Dust is grey and full of hair, and the surface flexes when pressed

Cause: Lath and plaster — Fix: Stop before you make it worse. Fixings go into the studs or joists behind, not into the laths, and repairs follow the lath and plaster method rather than the plasterboard one.

Questions people ask

Which wall type is best for hanging heavy things?

Solid masonry, comfortably. A properly sized plug or a resin anchor in sound brick or dense block will carry far more than any board fixing. On studwork the load has to reach the timber; on dry lining it has to reach the masonry behind; on lath and plaster it has to reach the studs, because the laths hold almost nothing.

Does the wall type change how I repair a crack?

Completely. A crack in solid plaster is raked out and filled or re-skimmed. A crack on a plasterboard wall usually follows a board joint and needs the tape addressed rather than the surface. A crack in lath and plaster often means the keys have failed behind it, and filling it alone achieves nothing.

How do I tell what my ceiling is without damaging it?

Tap it and look at an existing hole — around a light fitting, a smoke alarm or a loft hatch — where the edge of the material is visible. Board shows a clean 9.5 or 12.5mm layer with a paper face. Lath and plaster shows a thicker, coarser, hair-reinforced layer with timber behind.