A stud wall is the quickest way to get an extra room out of the house you already have: a bedroom split in two, a home office, a walk-in wardrobe or a utility area. It's a weekend or two of work, needs only simple tools, and done properly feels as solid as the rest of the house. This guide covers the rules first, then the frame, the doorway, the soundproofing and the finish. The stud wall planner prices every length of timber, sheet of board and bag of plaster at today's UK merchant prices.
The short version
Use 38 × 89mm CLS timber with studs at 400mm centres (600mm uses less timber). Fix the head plate into the ceiling joists and the sole plate to the floor, with one row of noggins at mid-height (two above 2.4m), plus extra noggins wherever you'll hang something heavy. Board with 12.5mm plasterboard, screws at 300mm centres, every board edge on a stud. A non-load-bearing wall normally doesn't need building regulations approval, but don't create a room whose only way out is through another room.
Planning the whole job? Our Stud wall room planner takes your measurements once and builds a single shopping list across every calculator you need.
1. Before you start: rules and room planning
- Building regulations. A non-load-bearing partition doesn't normally need approval in itself. What can need it is what the wall does: creating a new bedroom, blocking a fire escape route, or leaving a room without enough ventilation or daylight. If you're creating a habitable room, especially in a loft or on a floor above the ground floor, talk to building control first.
- Avoid an "inner room". If the only way out of the new room is through another room (for example, a bedroom you can only reach through another bedroom), it can break fire-escape rules. Plan the door so each room opens onto a hall or landing.
- Light and air. Check each new room still has a window. A room with no window needs mechanical ventilation and won't count as a bedroom when you sell.
- Radiators and sockets. Think now about which side gets the radiator, light switch and sockets. Moving them later means opening up the wall. Electrical work must meet Part P in England; new circuits are notifiable, so use a registered electrician for anything more than a simple extension of a socket.
- Renting or leasehold? Get the landlord's or freeholder's written consent first.
2. Find the joists before you buy anything
The head plate (the timber along the ceiling) has to be screwed into something solid, and that means the ceiling joists. Which way they run decides how easy the job is.
- Look at the floorboards upstairs or in the loft. Floorboards run across the joists, and the lines of nails show where each joist is.
- Use a joist detector on the ceiling, then confirm by drilling a small pilot hole where the wall will cover it.
- Wall running across the joists: the easy case. Screw the head plate into every joist it crosses.
- Wall running along the joists: line the wall up directly under a joist if you can. If not, you'll need access from above (loft or floorboards up) to fit timber noggins between the joists for the head plate to fix into.
- On the floor: on timber floors, fix the sole plate into the joists below (or noggins between them). On concrete, use frame fixings or concrete screws, and check for pipes in the screed first.
3. Plan and price your wall
Enter your wall and the planner counts the studs, plates, noggins and door framing, converts it all into 3m lengths of CLS, and adds the plasterboard, screws, tape and plaster. Then it prices everything we track at the cheapest UK merchant we've found. It uses the same maths as our stud wall calculator.
Assumes 38 × 89mm CLS in 3m lengths with 10% extra, one row of noggins (two above 2.4m), two extra studs and a 1m head per doorway, 2400 × 1200 × 12.5mm boards with 10% for cuts (doorways not deducted, the offcuts go above them), screws at about 12.5 per m², and skim at about 10m² per 25kg bag at 2mm. Prices are only shown for the products we track; insulation, screws, tape, jointing compound and the door itself aren't included in the total.
4. How the frame goes together
- Head plate and sole plate: one full-length timber along the ceiling and one along the floor, exactly in line. Use a laser or a plumb line to transfer the floor line up to the ceiling.
- Studs: vertical timbers cut to fit tightly between the plates, at 400mm or 600mm centres measured from one end. Every plasterboard edge has to land on a stud, so measure from the wall the boards will start from.
- Noggins: short horizontal pieces between the studs, one row at mid-height for walls up to 2.4m and two rows for taller walls. Stagger them up and down so you can screw through the stud into the end of each one.
- Extra noggins for heavy things: anywhere you'll hang a radiator, TV, wall cupboards, shelves or a basin, add noggins at the right height before boarding. Plasterboard fixings alone won't hold them for long.
- Doorway: buy the door and the lining (frame) set first, then build the opening to the size the lining instructions give. Double up the studs each side, fix a head across at the right height with a short stud above it, and cut the sole plate out of the doorway once the frame is fixed.
Take photos before you boardPhotograph every bay of the finished frame with a tape measure in shot, and keep the photos. Years later, they'll tell you exactly where the studs, noggins, cables and pipes are before you drill.
5. Building it, step by step
- Mark out. Snap or laser a line on the floor, then transfer it up the walls and across the ceiling, so the head plate lines up exactly with the sole plate. Check it's square to the room where it meets the walls.
- Fix the head plate into the ceiling joists (or noggins between them) with 90–100mm wood screws, at every joist.
- Fix the sole plate to the floor, leaving it whole across the doorway for now so the frame stays straight.
- Fix the end studs to the existing walls with frame fixings or wall plugs and screws, checked plumb.
- Cut and fit each stud to its own measured length (floors and ceilings are rarely parallel), a tight push fit, and screw or nail it at an angle through into both plates.
- Build the doorway: double studs, head and short stud above. Then cut out the sole plate between the door studs.
- Fit the noggins, staggered, plus the extras for heavy fixings.
- First fix: drill holes through the middle of the studs for cables and pipes (at least 50mm back from each face, or protected with steel plates), and fit back boxes for sockets and switches.
- Board one side, fill the cavity with insulation, then board the other side.
- Finish: tape and skim (or tape and joint), then fit the door lining, architrave and skirting.
6. Make it quiet: soundproofing that works
An empty stud wall with one layer of board each side passes a lot of sound, which matters if one side is a bedroom. In order of value for money:
| Upgrade | Why it works |
|---|---|
| Seal every gap with acoustic sealant | Sound leaks through gaps far more than through the boards. Seal the edges, round back boxes and round the door lining. |
| Acoustic insulation in the cavity | Absorbs sound bouncing around inside the wall. Cheap, and goes in before the second side is boarded. |
| Heavier boards | 15mm or acoustic plasterboard, or two layers of 12.5mm with the joints staggered. More mass stops more sound. |
| Back-to-back sockets? Don't. | Offset sockets on the two sides by at least one stud bay, or you've made a hole straight through the wall. |
| A solid door with seals | A hollow door is the weakest point. A solid-core door with a perimeter seal makes a bigger difference than people expect. |
7. Boarding and finishing
- Boards: 12.5mm plasterboard (2400 × 1200mm sheets cover 2.88m² each) is the standard for walls. Fix them vertically, so every long edge lands on a stud.
- Tight to the ceiling: lift each board up against the ceiling with a foot lifter. Any gap at the floor is hidden by the skirting.
- Screws: 38mm drywall screws for 12.5mm board (42mm for 15mm), at about 300mm centres, set just below the paper face without tearing it.
- Stagger the joints: don't let joints on the two sides fall on the same stud, and offset them around door openings so cracks don't run from the corners.
- Skim or tape and joint? Square-edge boards are usually skimmed with about 2mm of finishing plaster such as Multi-Finish, with scrim tape over the joints. A 25kg bag covers about 10m². Tapered-edge boards can be taped, filled and sanded instead, then painted, which is easier for a first-timer.
- Before painting: new plaster must be fully dry (it turns an even pale pink) and needs a mist coat of watered-down emulsion first. The paint calculator works out the tins.
8. Mistakes to avoid
- Head plate into plasterboard only. Without fixing into joists or noggins, the wall will rock.
- Studs cut to one length. Measure each one: floors and ceilings are rarely level.
- Board edges between studs. Every edge needs timber behind it, or the joint will crack.
- No noggins for heavy fixings. A TV or wall cupboard on plasterboard fixings alone will eventually sag.
- Building the doorway before buying the door. Build the opening to the lining set you've bought.
- Cables near the surface. Keep holes in the middle of the studs, or a picture hook could find a live wire.
- Forgetting the gaps. Unsealed edges and back-to-back sockets undo all your soundproofing.
- Painting too soon. Painting damp plaster traps moisture and the paint peels.
9. Stud wall checklist
Print this page (the planner is left out of the printout) and tick these off as you go:
- New room layout checked: own exit onto a hall or landing, a window, and building control asked if it's a new habitable room
- Joists found, and the direction they run in noted
- Radiator, switch and socket positions decided
- Door and lining set bought, and the opening size noted
- Timber, boards, screws, insulation, tape and plaster ordered
- Floor line marked and transferred to the ceiling
- Head plate fixed into joists, sole plate fixed down, end studs plumb
- Studs measured and fitted one by one, doorway framed, sole plate cut out
- Noggins in, plus extras for heavy fixings
- Cables and pipes run through the middle of the studs, back boxes fitted
- Frame photographed with a tape measure in shot
- One side boarded, insulation in, second side boarded, gaps sealed
- Skimmed or taped and jointed, left to dry, mist-coated
Need the numbers for a different wall? Use the stud wall calculator for the frame, the plasterboard calculator for boards and fixings, the plaster calculator for the skim, and the skirting board calculator to finish the room.