What a Lining Takes From the Room

Every fixed object on a lined wall moves forward with it: sockets, switches, radiator brackets, skirtings, architraves and sills. Whether those items are reset, extended or replaced falls inside the lining's scope even though none of them is part of the lining.

Electrical and plumbing first fix therefore has to be resolved before the wall is closed, because the void is not accessible afterwards and an accessory left at the old face is no longer at a face.

A lining brings the wall face forward, so the reveal becomes deeper and the frame sits further back. The reveal is also where a continuous lining is most often interrupted, because it cannot accept the same build-up as the wall — there is not the depth for it.

That is the hardest detail in the job and the one most often rushed. Where the lining carries insulation, the return at the reveal is also the coldest interior surface after the work, and the reveal is where condensation and mould appear before anywhere else in the room.

The internal shelf closing the reveal beneath a window is detailed against the frame, the plaster and any radiator, and all three of those relationships change when the wall face moves. A deeper reveal means a wider board, and a radiator that used to sit under the board may no longer clear it.

Externally, the sill is a separate element of the construction that manages water by its fall, its projection and the drip on its underside, and it is not moved by internal work. The internal and external sides of the same opening therefore diverge.

A door leaf near a corner has a swing that already depends on a few centimetres. Architraves have to be refixed to something at the new face, and a door lining that used to finish flush with the wall may now sit proud or recessed.

The loss is rarely uniform around a room, because linings are usually applied to some walls and not others. Where that leaves a plan asymmetric, the effect is most visible at doorways and at fitted furniture.

A few centimetres taken from a generous room is invisible; the same loss taken from a small bathroom, a corridor, a stair enclosure or a kitchen run with fitted units is a design change. An acoustic lining also takes room area from every wall it is applied to, which changes furniture, radiator positions and door swings before a single board is fixed.

Insulating internally and lining acoustically compete for the same wall face and the same room area, so combining them is a single design exercise rather than the sum of two separate ones.

Setting out has to be agreed against the finished room dimensions rather than against the existing rough wall. Boards are set to a line and a plane, and that setting-out determines every dimension that follows in the room.

With a lining built course by course or bonded to an irregular background, the finished thickness may be less predictable than the drawing suggests, which is another reason to agree the line before the first board goes up.

Rooms feel different in use once lined, and expectations about that are worth setting honestly at the start. A wall that used to be cool to the touch, a window that sat close to the face, and a radiator that projected a certain distance are all part of how a room is read.

None of that is a defect. It is the consequence of moving a surface, and it is easier to accept when it was described in advance.