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Wall insulation in London

Wall Insulation Across London, Inside and Out

Internal and external wall insulation for London homes, using breathable wood-fibre boards finished in lime plaster or render. Warmer walls, lower heat loss and a system that suits traditional solid-wall properties.

Book a property surveyor call Alister, 07757 336390
A bay window room after internal wall insulation, the walls finished in fresh plaster
Internal wall insulation, London, 2025

Warmer Solid Walls for London Homes

Cold walls and heat loss can make an older property uncomfortable and costly to heat. Insulating the walls helps a home keep its heat, feel more comfortable and use less energy. We specialise in sustainable, breathable systems, with wood-fibre insulation boards finished in lime plaster inside or lime render outside, chosen to work with many of London’s traditional solid-wall homes.

Not sure which system suits your home? Book a property survey and we will give you a recommendation for your walls. Our wall insulation guide compares the two systems in more detail.

Inside

Internal Wall Insulation in London

We fit wood-fibre insulation to the inner face of suitable external walls and finish it with breathable lime plaster. The outside of the house stays as it is, which suits many traditional and period homes.

  • Keeps the exterior unchanged.
  • Can often be done one room or one elevation at a time.
  • Warmer wall surfaces and more comfortable rooms.
  • Less heat escapes through the walls, which can lower heating demand.
  • Wood fibre and lime help manage moisture in compatible solid walls.

Outside

External Wall Insulation in London

Insulation boards, fixings, mesh and base coat go on the outside of the building, finished in a reinforced lime render or silicone render. The house is wrapped in a continuous layer, and the rooms keep their full size.

  • No loss of indoor space.
  • Fewer cold bridges at floors and internal wall junctions.
  • Most of the work happens outside the occupied rooms.
  • A new finish that protects and renews a tired façade.
  • The existing wall stays warmer, so the building holds heat more evenly.

How an Insulation Job Runs

  1. Property surveyWe assess the building fabric, its condition, moisture exposure, appearance, planning limits, the space available and your budget.
  2. Recommendation and quotationWe recommend internal or external insulation for your home and confirm the full scope and total cost in a written quotation.
  3. PreparationWalls are taken back where needed, and skirting boards, radiators, sockets or external fittings are moved so the boards can run behind them.
  4. Insulation boardsSTEICO wood-fibre boards are fixed with SecilTek Isovit lime bonding plaster and hammer fixings.
  5. Base coat and meshA base coat goes over the boards, reinforced with a fibreglass mesh.
  6. Finish and detailingLime plaster inside, or a lime or silicone render outside. Junctions at floors, ceilings, windows, roof edges and the base of the wall are detailed with care to limit cold bridges, condensation and water ingress.

On one London bay window room in 2025, the wall went back to brick in January and by April had 80 mm of wood fibre, mesh and lime render in place. Both stages are in our videos.

Insulation Products We Install

Each system is built up from board, base coat and finish. More detail on every product is on our materials page.

Guide Prices for Wall Insulation in London

Internal wall insulation

£50 to £150 per m²

Wood-fibre insulation with a breathable lime-plaster finish

External wall insulation

£150 to £250 per m²

Wood-fibre insulation with reinforced lime render or another suitable external finish

Guide prices include VAT. The final price depends on the insulation thickness, the chosen lime system and the preparation work, and is subject to a property survey, wall condition, access, detailing, finish, scaffolding and any required permissions. A written quotation confirms the full scope and total cost.

Wall Insulation in Every Part of London

We survey and insulate homes across Greater London from our base in Shepherd’s Bush, W12. Our insulation and render work so far includes internal wall insulation in London homes, insulation and silicone render in Barnet and High Barnet, cement boards and silicone render in Hoxton, and a Lime Green insulating render in Penge.

West London

Shepherd’s Bush, Kensington, Notting Hill, Fulham, Chelsea, Chiswick and nearby.

Central London

Homes across Central London, each surveyed before the work is priced.

North London

Barnet, High Barnet, Highgate, Hampstead and nearby.

East London

Hoxton, Shoreditch and the rest of East London.

South London

Penge, Clapham and South East London, where we ran a community insulation workshop with SELCE.

We Show Homeowners How It Works

Invited by Flavia Bertram of SELCE, we ran a demonstration of external and internal wall insulation at the Besson Street Community Garden in South East London. Fifteen to twenty homeowners came with questions and built a mock wall themselves, with wood-fibre panels, lime adhesive and base coat, and glass fibre mesh.

Read about the workshop, or see the insulation jobs on our home page.

Homeowners fixing wood-fibre panels to the mock wall at the Besson Street workshop A finished Lime Green insulated render gable between black timbers, Penge

Wall Insulation Questions

Should I choose internal or external wall insulation?

It depends on the building. Internal insulation keeps the outside of the house unchanged and can be done a room at a time, with a small loss of floor space. External insulation keeps every room its full size and creates a more continuous layer, but it changes the look of the façade and may need planning permission. We assess the walls, their condition, moisture exposure, appearance, planning limits, space and budget during a property survey and recommend the one that suits your home.

How much does wall insulation cost in London?

As a guide, internal wall insulation with wood fibre and a lime plaster finish is £50 to £150 per m², and external wall insulation with wood fibre and a reinforced lime render or other suitable finish is £150 to £250 per m². Both guide prices include VAT. The final price depends on the insulation thickness, the lime system, the preparation, access, scaffolding and any permissions, and is confirmed in a written quotation after the survey.

Will internal insulation make my rooms smaller?

Slightly. The insulation reduces the usable floor area of each treated room a little, and skirting boards, radiators, sockets and other fittings may need to be moved. We plan these details with you before work starts.

Do I need planning permission for external wall insulation?

Sometimes. External insulation changes the appearance and thickness of the façade, so planning permission or other consent may be needed, particularly for listed buildings and homes in conservation areas. We take this into account at the survey stage.

Why do you use wood fibre and lime?

Wood fibre boards and lime plaster or render are breathable, so moisture can move through compatible solid-wall construction. That makes them a good fit for many of London’s traditional solid-wall homes, and they are sustainable materials.

Can the work be done one room at a time?

Internal wall insulation can often be phased room by room or one elevation at a time. External insulation is usually done as a whole elevation or the whole building. Rooms with internal insulation normally need redecorating afterwards.

Book a Wall Insulation Survey

Arrange a property survey. We will talk through your goals, assess your walls and recommend the internal or external system that suits your home.

Arrange a property survey

All recommendations are subject to a property survey, the condition of the building and any required planning permission or listed-building consent.

Need plastering too? See our plastering services across London, from skimming and dry lining to lime plaster for period homes.

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