Soundproofing a party wall in London typically costs £120 to £180 per m² supplied, fitted and plastered. A wall in one room, 10 to 14 m², comes to £1,500 to £2,800; a wall through both ground floor rooms of a terrace is usually £2,900 to £4,300. The price buys a built system, not a board: a frame separated from the wall, acoustic mineral wool in the void and two layers of dense acoustic plasterboard. It is charged at 20% VAT.
Key takeaways
- Indicative party wall soundproofing cost: £120 to £180 per m², or £1,500 to £2,800 for a typical room wall of 10 to 14 m².
- A proper system has three parts: mass (two layers of 15 mm acoustic board), decoupling (independent stud or resilient bars) and absorption (mineral wool slab).
- A single "soundproof board" glued to the wall does very little, because it stays fixed to the structure that is vibrating.
- You lose 75 to 100 mm of room depth with an independent stud wall, or around 50 mm with resilient bars.
- It cuts voices and television well; deep bass and noise that travels round the wall through floors and chimney breasts are reduced, not removed.
- Soundproofing is 20% VAT. It is not an energy-saving material under HMRC VAT Notice 708/6.
How much does it cost to soundproof a party wall?
Indicative 2026 ranges for London, Surrey, Kent and Hertfordshire, supply and fit, plastered and ready to decorate. The rate covers the frame or bars, mineral wool, two layers of acoustic board, sealant and plastering. Decoration, moving sockets and radiators, and any work on the floor or chimney breast are separate lines.
| Job | Wall area | Indicative cost |
|---|---|---|
| Party wall, per m² | Any | £120 to £180 per m² |
| One bedroom or living room wall | 10 to 14 m² | £1,500 to £2,800 |
| Front and back reception, one wall | 20 to 28 m² | £2,900 to £4,300 |
| Whole party wall, two floors of a terrace | 45 to 55 m² | £5,400 to £9,900 |
| Resilient bars (component) | per m² | £10 per m² from our quote book |
| Double 15 mm acoustic board (component) | per m² | £45 per m² from our quote book |
To estimate your own wall, multiply its length by the room height: a 4 m wall in a 2.6 m room is about 10.4 m². Small walls cost more per m² than large ones because set-up and plastering are much the same either way.
What is a party wall soundproofing system?
Sound gets through a single brick party wall because the wall itself vibrates, and anything fixed rigidly to it vibrates too. So the lining has to be separated from the wall, heavy enough to resist being moved by sound, and backed by something that soaks up the energy in the gap. Mass, decoupling and absorption. Leave one out and the result disappoints.
Independent stud wall
A new timber or metal frame is built 10 to 25 mm clear of the party wall, fixed only to the floor and ceiling. The void is filled with acoustic mineral wool such as ROCKWOOL RWA45 slab, then two layers of 15 mm acoustic plasterboard go on with joints staggered and sealed. This is the best performing option and the one we use where there is room to lose 75 to 100 mm.
Resilient bar system
Where space is tight, battens go on the wall, resilient bars (thin sprung steel channels) are fixed across them, and the boards hang on the bars so they never touch the wall directly. Mineral wool sits between the battens. It takes around 50 mm and performs a step below an independent frame, but far above a bonded board.
What does party wall soundproofing actually stop?
Walls carry mostly airborne noise: voices, television, music, a dog barking. A well built independent wall takes normal conversation next door below what you can hear and turns a loud television into a murmur. That is the realistic aim.
Three things are harder. Deep bass moves the whole structure and is reduced but not removed. Impact noise such as doors slamming enters the brickwork directly and travels along it. And flanking noise goes round the lining through the floor joists, the ceiling void and the chimney breast, which is why we survey the whole room and not just the wall. The acoustic party wall insulation guide covers the theory. If the noise is footsteps from a flat above, the fix is a ceiling system: see how to soundproof a ceiling from upstairs neighbours.
How much room do you lose?
| System | Depth taken from the room | Best for |
|---|---|---|
| Independent stud wall | 75 to 100 mm | Bedrooms and living rooms where performance matters most |
| Resilient bar system | About 50 mm | Narrow rooms, hallways, box rooms |
| Bonded board (not recommended) | 20 to 30 mm | Very little; we do not sell it as a fix |
What pushes the price up or down
- Wall area. The biggest factor. Two rooms on one visit cost less per m² than one.
- System choice. An independent frame uses more timber and labour than resilient bars, so it sits at the upper end of the range.
- Chimney breasts and alcoves. Returns and reveals add board, cutting and plastering time.
- Services. Sockets, switches, radiators and pipes on the wall have to be extended or moved.
- Flanking. Treating a floor void or adding a floating floor overlay (£60 to £110 per m²) is an extra line when the survey shows it is needed.
VAT, guarantee and how we quote
Soundproofing is charged at 20% VAT. HMRC's 0% rate for energy-saving materials only applies to work installed for its thermal insulating qualities, and a party wall has next door's heated house on the other side, so there is nothing to insulate. Where a lining runs onto an external wall and carries thermal insulation as well, that element is 0% until 31 March 2027 and the quote shows the split. See 0% VAT on energy-saving materials.
- Free survey. We look at the wall, ask what you hear and when, and check the floor, ceiling and chimney breast for flanking paths.
- Fixed written quote naming the system, the depth it takes, the materials and what it will and will not do for your noise.
- Installation by our own team, usually one to three days per room including plastering.
- Photographs of the build-up before it is boarded, and a written guarantee for the work.
The soundproofing service page lists the materials we use. If the room also has a cold external wall, internal wall insulation can be built into the same visit.
Frequently asked questions
How much does it cost to soundproof a party wall in a terraced house?
Indicatively £120 to £180 per m² supplied, fitted and plastered. One room wall of 10 to 14 m² is £1,500 to £2,800; both ground floor rooms together are around £2,900 to £4,300. VAT is 20%. A fixed price follows a free survey.
Does soundproofing a party wall actually work?
Yes, when it is a full system: a frame or resilient bars separated from the wall, mineral wool in the void and two layers of acoustic board with sealed joints. It brings normal conversation next door below hearing level and reduces television and music to a murmur. Deep bass and heavy impact are reduced rather than removed.
How much space does soundproofing take from a room?
An independent stud wall takes 75 to 100 mm; a resilient bar system around 50 mm. On a typical 3.5 m wide room that is under 3% of the floor area. The exact depth is stated on the quote.
Do I need my neighbour's permission to soundproof my side of the party wall?
A lining built on your side and fixed to your own floor and ceiling is your own work in your own home; an independent frame does not fix into the party wall at all. If the survey shows the neighbour's floor needs to change, that would need their agreement, and we will say so.
Is party wall soundproofing 0% VAT like insulation?
No. It is 20% VAT. The 0% rate is for energy-saving materials installed for their thermal qualities, and soundproofing does not qualify. If the same lining also thermally insulates an external wall, that part is 0% and the quote shows the split.