How do I build a stud wall?

A timber stud partition is four parts: a sole plate on the floor, a head plate at the ceiling, vertical studs between them, and horizontal noggins to stiffen the studs and support board edges. It is straightforward carpentry, and the two things that determine whether it comes out well are the setting out and whether the plates are fixed into something real.

Safety

What you'll need

• CLS or sawn timber for plates, studs and noggins
• Plasterboard
• Screws — for timber, for the floor and for masonry
• Long spirit level and a plumb bob or laser
• Chalk line
• Saw and a drill driver
• Joist and cable detector
• Acoustic or general insulation for the void (optional)

Step by step

1. Confirm the wall is allowed and sensible before you build it.Dividing a room can affect escape from a bedroom, ventilation, natural light, and whether a room still meets its intended use. In a flat, check the lease. If a habitable room is being created or divided, building regulations can apply even to a non-structural partition.
2. Establish what is under the floor and above the ceiling.Find the joist direction in both. A partition running at right angles to the joists spreads its load across several of them, which is what you want. One running parallel can land between two joists with nothing beneath it, and on an upper floor that needs support added or an engineer's view.
3. Set out the line on the floor.Measure from an existing wall at both ends, mark, and snap a chalk line. Measure from the same reference at both ends rather than from opposite walls, because rooms are not parallel.
4. Transfer the line to the ceiling with a plumb bob or a laser.Do not measure the ceiling separately. The head plate must be directly above the sole plate or the wall will lean, and no amount of care with the studs afterwards will correct it.
5. Fix the sole plate.Screwed through the floor into the joists on a timber floor, or plugged and screwed into a solid floor. On a finished floor, decide first whether the plate sits on top of it or the floor is cut back to the boards.
6. Fix the head plate into the joists above.Screws into the joists where the wall crosses them. Where the partition runs parallel to the joists and does not sit under one, noggins have to be fitted between two joists from above so the head plate has something to fix to. A head plate screwed only into ceiling plasterboard is not a fixing.
7. Fix the end studs to the existing walls.Plugged and screwed into masonry, or screwed into the studs of an existing partition. Both ends, full height. This is what stops the wall swaying.
8. Measure and cut each stud individually.Ceilings are not level. Measure the gap between plates at every stud position and cut to that measurement, so each stud is a tight fit rather than a nominal one.
9. Fit the studs at your chosen centres.Four hundred millimetre centres for a stiffer wall or where 9.5mm board is being used; 600mm where 12.5mm board is used and the wall is not carrying anything. Set them out from one end so that board edges land on stud centres.
10. Fit noggins.A row at mid-height as a minimum, staggered so you can screw through the studs into each end. Add more wherever a horizontal board joint will fall, and wherever anything will later be fixed to the wall — a TV, a radiator, a basin, a handrail, shelves, a wall unit.
11. Form any door opening now.Doubled studs each side, a head over the opening, and short studs from the head to the head plate. Set the opening out from the door's actual size plus the lining and a fitting tolerance.
12. Run the services before boarding.Cables through drilled holes near the centre of the studs' depth, protected with grommets or steel plates where they could be hit by a screw; pipework likewise. Every socket and switch position decided now.
13. Insulate the void.Mineral wool friction-fitted between the studs makes a substantial difference to sound transmission and costs very little at this stage. It is essentially impossible to add later.
14. Board both sides, then tape or skim.Boards fixed to every stud and noggin, joints staggered between the two faces, a 10mm gap at the floor, and a bead of acoustic sealant round the perimeter if sound matters.

Tips

• Buy timber and sort it as you go: sight along each length and reject anything bowed or twisted, or use the worst pieces for noggins where the bend does not matter.
• Where the new wall meets an existing wall or ceiling that is not flat, pack behind the plates rather than forcing them — a plate pulled tight to a hollow wall pulls the whole partition out of plumb.
• Photograph the wall fully framed and serviced before boarding. Cable runs, noggin positions and pipe routes are worth having on record forever.
• If the wall is to carry a wall-hung basin, a TV or a radiator, put a full-width plywood panel between the studs at the right height rather than a single noggin — it gives you freedom over the exact fixing position later.

Common mistakes

• Fixing the head plate into the ceiling board — Plasterboard cannot hold a partition. The head plate must reach joists, or noggins fitted between joists for the purpose.
• Setting the head plate out by measuring from the walls — Walls are not plumb. The head plate is positioned from the sole plate with a plumb bob or laser, or the wall leans.
• Cutting all the studs to one length — Ceiling heights vary across a room, often by 10mm or more. Studs cut to one measurement leave gaps at the top in some places and force the head plate up in others.
• Forgetting noggins for future fixings — The single most common regret. Fitting a noggin behind board is a wall repair; fitting one now is thirty seconds.
• Not insulating the void — An empty stud wall transmits sound remarkably well and drums. Mineral wool at the framing stage is cheap and cannot sensibly be retrofitted.

Questions people ask