How to build a stud wall

Non-load-bearing interior partition · Timber studs and plasterboard · Step by step

A stud wall is the most common way to subdivide interior space in residential construction. It is non-load-bearing and consists of a timber frame — sole plate, top plate and vertical studs — clad with plasterboard on both sides. Sound insulation is typically placed between the boards. This guide takes you through the entire process from planning through to finished skirting and architrave.

Materials you will need

Framing timber

• Sole plate (bottom plate): 48×98 mm structural timber, minimum C18 (C24 recommended) — fixed to the floor
• Top plate: 48×98 mm — fixed to ceiling or floor structure above
• Studs: 48×98 mm, measured between the fitted plates and adjusted for required clearance
• Door opening (where applicable): double studs + double header at 48×98 mm

Board cladding

• Standard plasterboard: 12.5 mm, 1,200 × 2,400 mm — for living rooms, bedrooms and hallways
• Moisture-resistant board (green/blue): 12.5 mm — for kitchens, bathrooms and utility rooms
• Fire-rated board (red): where a fire compartment wall is required (REI 30/60)

Insulation

• Acoustic insulation: 70 mm mineral wool (stone wool or glass wool) — reduces airborne sound transmission by approximately 5–8 dB
• Thermal insulation is rarely necessary for an interior stud wall
• In wet rooms: use moisture-resistant insulation (stone wool)

Fixings

• Plates to concrete (powder-actuated): Hilti/Spit shot fasteners — fast installation into solid concrete, requires specialist tool
• Plates to concrete (expansion anchors): Ø8 mm, minimum 50 mm embedment, max 600 mm centres — use where powder-actuated fasteners are not suitable
• Plates to timber: 4.5×90 mm structural screws, 600 mm centres
• Studs to plates: 4.5×75 mm angle brackets or toenailed with 3.1×90 mm nails
• Plasterboard: 3.5×35 mm drywall screws, 200 mm centres at edges, 300 mm centres at intermediate studs
• Vapour barrier: 0.15 mm polyethylene film (only at external walls or where required) + vapour-barrier tape at joints

Trim and architrave

• Skirting board: 12×58 mm or 15×70 mm — along the wall/floor junction
• Cornice/coving: 12×58 mm — along the wall/ceiling junction (optional)
• Door architrave: 21×70 mm — framing the door opening
• Adhesive and pin nailer (23 ga nails, 35–50 mm) for trim

How thick is a finished stud wall?

The finished thickness is simply the stud width plus the board thickness on every side you board. Nothing else adds to it — insulation sits inside the stud depth, and the plates are the same width as the studs. Work it out before you set out the wall: the figure decides how much floor area you lose, and it is the dimension your door linings have to match.

Stud spacing — which centres to use

Spacing is measured centre to centre, and only two values are in normal use: 600 mm and 400 mm. Both divide evenly into a 1,200 mm board width, so sheet edges always land on a stud — that is the whole reason those numbers exist, and it is why you should not invent a spacing in between.

• 600 mm — the default. Fine for 12.5 mm board on a normal room-height partition.
• 400 mm — use where the wall has to work harder. Tiled surfaces, walls carrying wall-hung units, thinner board, walls above normal room height, and any fire-rated or acoustic build-up whose tested specification calls for it.

Metal stud partitions

The alternative to timber is light-gauge galvanised steel: C-shaped studs that drop into U-shaped track fixed to the floor and ceiling. It is the default for commercial fit-out and increasingly common in housing, because the studs are dead straight, do not shrink, twist or burn, and a partition goes up considerably faster.

• Common web widths: 48, 70, 92 and 146 mm — track is a fraction wider so the stud slides inside it
• Track first: fix floor and ceiling track to the setting-out line at 600 mm centres, then cut studs and twist them into place
• Stud length: cut roughly 10 mm short of the floor-to-ceiling dimension so the stud locates without binding — unlike timber, you are not filling the gap between two plates
• No noggins: a steel C-stud does not need mid-height blocking for racking, and service holes come pre-punched in the web
• Shorter board screws: self-drilling screws into 0.5 mm steel, typically 25 mm for a single layer against 35 mm into timber

Drawings

Step by step

Step 1 — Planning and setting out

Mark the wall position on the floor with a chalk line or laser level. Mark where any door openings will be. Remember that the finished wall will consume approximately 125 mm of floor area (two plasterboard sheets + stud + plates).

• Check that the planned position does not conflict with pipes, cables or structural elements in the ceiling
• Plumb up from the floor line to the ceiling using a laser or plumb bob
• Mark stud positions on the plates (600 mm centres) before fixing

Step 2 — Fix the sole plate

Lay the sole plate along the chalk line. At door openings, the sole plate is cut and stops at the inner face of the door studs — the sole plate must not run across a door opening.

• Concrete floor: use Ø8 mm expansion anchors, minimum 50 mm embedment depth, at 600 mm centres
• Timber floor: 4.5×90 mm screws through the plate and floor boards and into the joist
• Always fix at stud positions — avoid fixing mid-bay between studs

Step 3 — Fix the top plate

Plumb up from the sole plate and fix the top plate to the ceiling. Into concrete: expansion anchors. Into timber floor structure: screw into the joist — never fix only into floor boarding.

Step 4 — Studs

Studs are set at 600 mm centres, measured from centreline to centreline. This gives optimal use of 1,200 mm wide plasterboard sheets — two sheets always meet on a stud.

• Measure stud length directly between the fitted plates and subtract the required clearance — do not calculate from room height
• Start with corner studs, then work inward from the corners
• Fix with stud angle brackets or toenailing — minimum 2 nails or screws per side
• Check with a spirit level: each stud must be perfectly plumb

Step 5 — Door framing

At door openings, double studs are set on each side of the opening. A double header of the same section (48×98 mm) is fitted above the opening to distribute the plasterboard load across the gap.

• Set the rough opening from the door manufacturer's stated rough-opening size for that specific door set, plus a small fitting/packing gap (often ~10–15 mm in total) so the frame can be shimmed plumb. Figures sometimes quoted — e.g. ~860 mm clear for a 9M (~900 mm) door set, ~760 mm for an 8M (~800 mm) set — are typical examples only; door modules and tolerances vary by supplier and country
• Double studs are bolted together with 4.5×90 mm screws at 400 mm centres
• Short cripple studs run from the header up to the top plate at 600 mm centres

Step 6 — Services: pipes, cables and ventilation

Before closing the wall: install all pipes, cables and ventilation ducts. This is the last opportunity to do so without opening up plasterboard.

• Route cables through holes drilled near the centre of the stud rather than notches in the edge, and keep holes/notches within the limits allowed for the stud so you do not weaken it. Where a cable runs close to the board face, fit a steel protection plate so screws cannot pierce it, and keep wiring within the safe zones required by your local electrical rules
• Mark electrical back-box positions on the studs in pencil
• Confirm with a qualified electrician that wiring complies with the relevant electrical regulations

Step 7 — Insulation

Cut mineral wool to the correct width (600 mm, matching the stud spacing) and press firmly between the studs. The insulation must sit tightly with no air gaps.

• Cut with a knife against a straight edge — add approximately 10 mm to the width for a friction fit
• Fill carefully around electrical back-boxes — voids reduce sound reduction performance
• Sound reduction is a property of the whole tested wall (studs, board layers, cavity, insulation and seals), not the insulation on its own — a single-stud wall with 70 mm mineral wool might reach roughly Rw 43–48 dB, but for a specific acoustic target use a manufacturer/system-tested build-up (e.g. double boards, staggered or twin studs, resilient bars)

Step 8 — Vapour barrier (where required)

A vapour/air barrier belongs in external walls (on the warm side) — not in an interior partition between two heated rooms, where it is unnecessary and can trap moisture. Wet rooms are a special case: the wall is protected by a single, defined waterproofing system (the tiling/wet-room membrane). Do not also add a separate polyethylene vapour barrier behind that membrane — two low-permeability layers can trap moisture between them. Follow one approved wet-room system and your local wet-room rules.

• The vapour barrier goes on the warm side (room side) of the insulation in an external wall
• Overlap joints by at least 200 mm and seal with vapour-barrier tape
• Staple to the studs

Step 9 — Plasterboard, first side

Start on the side with the best access. Lift the board up to the ceiling — use a board lifter or wedges — and fix from the centre outwards towards the edges.

• Screw spacing: 200 mm at edges, 300 mm at intermediate studs
• Screws should be set approximately 12 mm from the board edge — too close to the edge will cause the plaster core to break
• The screw head should sit 0.5–1 mm below the face (a slight dimple) without tearing through the paper
• Always start with a full board in the corner — fill with cut pieces towards the opposite wall
• Stagger horizontal joints on opposite faces of the wall to improve sound reduction

Step 10 — Jointing and sanding

All joints and screw heads are filled and sanded to a smooth surface in three coats:

1. Tape coat: bed paper joint tape into all butt joints and apply a thin coat of joint compound
2. Second coat: after drying (approximately 24 h), apply a wider, thinner coat
3. Finish coat + sanding: rake lighting reveals any ridges — sand with 120-grit paper

Step 11 — Plasterboard, second side

Fix plasterboard on the second side. Ensure that vertical joints do not align with those on the first side — offset joints improve sound reduction performance.

Step 12 — Trim and finishing

• Prime and paint the wall before fitting trim — saves masking tape
• Cut skirting and architrave at 45° mitre joints using a mitre saw
• Fix with adhesive (construction adhesive) + pin nailer, 35 mm nails
• Fill the gap between trim and wall/floor with paintable acrylic sealant

Rules of thumb and dimensions

Common Mistakes

• ✗Forgetting the top plate in the material count — you need as much top-plate timber as bottom plate; count both in your estimate
• ✗Wrong stud length — studs fill the gap between bottom and top plate, not floor to ceiling; stud length = room height minus two plate thicknesses
• ✗Not framing the opening properly — a door opening needs a stud each side and a head member above to support the board and door frame. In a non-load-bearing partition this head is not a structural lintel; but if the wall is actually load-bearing, a proper engineered lintel and supports are required
• ✗Insufficient waste allowance — cuts at corners, openings and joints typically add 10–15% waste to stud and board quantities
• ✗Confusing nominal and actual dimensions — a "48×98 mm" stud actually measures slightly less; always use actual sizes for detailed design
• ✗Forgetting noggings — horizontal blocking halfway up the studs increases racking strength and is required by most plasterboard fixing guides
• ✗Boarding a metal stud wall before fitting pattresses — a steel stud will not hold a heavy fixing, so any radiator, cabinet or basin needs a plywood or timber backing panel installed while the wall is still open
• ✗Cutting metal studs to the full floor-to-ceiling height — they sit inside the track and are cut roughly 10 mm short, unlike timber studs which fill the gap between two plates
• ✗Ordering door linings to the stud width — they have to match the finished wall thickness, which includes the board on both faces

Calculate your materials

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