Building a Stud Wall: Timber Sizes, Noggins, Fixings & Soundproofing

Quick Answer: A typical domestic stud wall uses 75×50mm or 100×50mm C16-grade timber at 400mm or 600mm centres. The wall must be independently plumb and tied to the structure above — not just wedged between floor and ceiling. Soundproofing performance is governed by Approved Document E (resistance to airborne sound); a standard stud wall with 60mm mineral wool quilt achieves approximately 43 dB Rw, meeting the 43 dB minimum for walls between rooms in a converted dwelling.

Summary

Non-loadbearing stud partition walls are one of the most common carpentry tasks in UK domestic work — splitting bedrooms, creating en-suites, adding home offices, or making over a floor plan. The job appears simple but is regularly done badly: walls that flex, walls that transmit sound, walls that were never tied to the structure, and walls that have been built without considering the impact on ventilation, heating, or means of escape.

The Building Regulations position is important to understand. Building a new internal partition wall is generally exempt from Building Regulations notification in its own right, but if the partition wall affects a habitable room's means of escape, ventilation, or fire separation, those regulatory requirements are triggered. Converting a single room into two bedrooms, for example, may trigger Part B (fire) and Part F (ventilation) requirements.

Soundproofing is the most common callback issue. Customers expect privacy between rooms but a bare stud wall with plasterboard each side transmits conversation clearly. Meeting even the minimum requirements of Part E requires mineral wool quilt between the studs — and premium performance requires independent leaf construction.

Key Facts

Quick Reference Table

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Wall Height Min Stud Size Max Stud Centres Notes
Up to 2.4m 75×50mm C16 600mm Single noggin at mid-height
2.4m–2.7m 75×50mm C16 400mm Single noggin at mid-height
2.7m–3.0m 100×50mm C16 400mm Two noggins at thirds
3.0m–3.6m 100×50mm C16 400mm Two noggins; engineer check advisable
Over 3.6m Engineer design — Exceeds standard timber partition scope
Sound Performance Approx Rw (dB) Construction
Bare stud, single layer 12.5mm each side 33–35 No insulation
Stud with 60mm mineral wool 40–43 Standard quilt fill
Stud with 100mm mineral wool + resilient bars 45–50 Resilient bars one side
Independent leaf (staggered or separate studs) 50–55 High-performance separation
Solid 100mm blockwork 43–46 For comparison

Detailed Guidance

Marking Out and Setting Up

  1. Establish the line of the wall on the floor using a chalk line or laser — check it is square to the room if required
  2. Mark the sole plate position; check for any underfloor services using a cable and pipe detector
  3. Transfer the line to the ceiling using a plumb bob or rotary laser level
  4. Mark the head plate position on the ceiling

Always check: does the partition wall run parallel to or across floor joists? If parallel, the sole plate may fall between joists with no fixings available — additional blocking between joists may be needed before fixing the plate.

Framing Up

Sole plate first: Fix the sole plate along the floor line, leaving a gap only where doorways will be. Do not fit a full-length sole plate and cut out later — it is neater and stronger to frame around the opening from the start.

Head plate: Fix to ceiling joists or noggins between joists. Never just screw into plasterboard ceiling — the head plate must be fixed to structure.

Studs: Measure each stud individually — floors and ceilings are rarely perfectly level or parallel. Cut each stud 3–4mm short for easy fitting; a stud that is too long will push the head plate off its line.

Fixing studs:

Door openings: Frame using trimmer (inner) studs to take the door lining; king (outer) studs; and a head (lintel) over the opening. For stud walls, a 47×100mm or 47×150mm header is adequate for non-loadbearing openings.

Noggins

Fit noggins at:

Soundproofing

To achieve useful sound reduction:

  1. Fill stud bays with 60mm mineral wool acoustic quilt (e.g. Knauf Acoustic Roll, Isover Party Wall Roll) — not standard loft roll, which is less dense
  2. Use two layers of 12.5mm plasterboard rather than one layer of 15mm — the mass law means that two separate layers with an air gap between them outperform a single thicker layer
  3. Fix one layer of board directly to the studs; the second layer staggered-joint with grab adhesive and screws
  4. For improved performance, use resilient bars (e.g. Gyproc Resilient Bar) fixed horizontally across the studs at 600mm centres; fix the plasterboard to the bars, not directly to the studs. This decouples the boards from the structure and eliminates direct vibration transmission
  5. Seal all perimeter joints with acoustic sealant — flanking transmission around the edges of the wall is a major cause of poor acoustic performance

Electrical and Plumbing Runs

Frequently Asked Questions

Does building a stud wall need Building Regulations approval?

Building a non-loadbearing internal partition in an existing dwelling is generally permitted development and does not require Building Regulations approval for the wall itself. However, if the new wall creates a new habitable room (e.g. a bedroom), the new room must comply with Part F (ventilation), Part L (insulation if new window is added), and Part B (means of escape — the room needs an openable window to outside if above ground floor). A building control application may be advisable if you are unsure.

What is the difference between C16 and C24 timber for stud walls?

C16 and C24 are strength grades for softwood timber. C16 is the standard grade used for most domestic stud walls and is widely available and cost-effective. C24 is stronger — used for structural floor joists and roof rafters where span tables require it. For non-loadbearing stud partitions, C16 is entirely adequate.

Can I put a stud wall on a suspended timber floor?

Yes, but you must position the sole plate over a joist or add noggings between joists to create a solid fixing point. If the partition runs parallel to the joists, a single joist may not be adequate — check with a structural engineer if the wall is long and heavy (especially if also adding a masonry veneer or heavy finishes).

How do I get the wall perfectly plumb?

Fit the sole plate and head plate accurately first, using a level and a plumb bob or rotary laser. If both plates are on the same plumb line, every stud should stand plumb automatically. Check each stud with a spirit level as you go — small errors in plate position can accumulate. Use packing shims at the plate fixings if the floor or ceiling is out of level.

How much weight can a stud wall carry?

A standard 75×50mm stud wall with plasterboard both sides can carry normal picture rails, shelves, and standard radiators via noggins. For heavy items — large TVs, kitchen cabinets mounted on an internal partition, heavy bathroom fittings — fit a full sheet of 18mm WBP ply behind the plasterboard, screwed to the studs. This gives a fixing anywhere on the wall surface.

Regulations & Standards