Solid wall insulation · Greater London
Solid wall insulation in Barnet
We quote solid wall insulation for homes in Barnet (EN5) and nearby Potters Bar and Borehamwood, with guide prices online and a free survey to fix the price. For Barnet homeowners weighing external against internal insulation, the survey sets out both with prices.
- Free survey in EN5 and nearby
- Guide price from £75 per m² + scaffold, 0% VAT
- Fixed written price before work starts
Free survey in Barnet
Postcode, service and a phone number is all we need.
What the job covers
- Breathable options for stone and lime-mortared walls
- Both can be done in stages, elevation by elevation or room by room
- Internal insulation suits single rooms or where the outside can't change
- In England and Wales, Building Regulations apply when more than half of a wall is treated
Barnet: walls, weather and approvals
As well as Barnet itself, we quote in Potters Bar, Borehamwood and Finchley. London's housing includes a large stock of Victorian and Edwardian solid-wall terraces, inter-war semis and post-war blocks, and conservation areas cover many streets — so planning is often the first question for external work.
Much of Greater London sits in the lower wind-driven rain exposure bands, which keeps the choice of finishes wide — though hilltop, coastal and exposed gable walls can still need a tougher specification, so we check the actual site.
For solid-walled homes in Barnet, we check wall thickness and age first to confirm there's no cavity to fill.
- Postcode district
- EN5
- County or area
- Greater London
- Nation
- England
- Nearby
- Potters Bar, Borehamwood, Finchley, Muswell Hill
Permissions in England
For a house in Barnet, external insulation or render is often permitted development if it looks similar to the existing walls; conservation areas, flats, commercial buildings and listed buildings need permission or consent, so we check your address first.
If the work covers more than half of a wall, or a quarter of the building's whole envelope, it counts as renovating a thermal element, with a target of about 0.30 W/m²K where feasible.
How can I tell if my walls are solid?
Measure the wall thickness at a window or door: about 225mm (9 inches) of brick usually means solid, while 260mm or more often means a cavity. On exposed brick, a pattern with bricks laid end-on (headers) every few courses points to solid construction. Stone walls are usually solid regardless of thickness. Age is a strong clue too — most homes built before the 1920s are solid-walled.
Solid wall insulation prices in Barnet
| Item | Guide price | Notes |
|---|---|---|
| External (EWI) | £105–£210 per m²0% VAT | By board and finish |
| Internal (IWI) | £75–£130 per m²0% VAT | Plus making good |
| Survey and written recommendation | Free with a quote |
Confirmed by a fixed written quote after survey. 0% VAT: installing insulation in a home is zero-rated until 31 March 2027, so these figures are the total; 5% applies from 1 April 2027.
From enquiry to finished wall
Enquiry
Send your postcode and a few details.
Measured survey
Walls, damp, eaves, cills and services recorded.
Written price
A fixed price with the specification attached.
Work and handover
Installed, inspected and documents handed over.
Solid wall insulation in Barnet: questions
Can I do one wall at a time?
Yes. Many owners start with the coldest or most exposed elevation, often a gable end.
Does solid wall insulation cause condensation?
It can if detailed poorly, particularly internally. A condensation risk check for the proposed build-up and careful detailing at joists, reveals and corners avoid it.
Is solid wall insulation worth it?
For many solid-walled homes it's one of the biggest single improvements to comfort, because the walls are often the largest heat-loss area. Savings depend on the home and heating, so we don't promise a figure.
Do you cover Barnet?
Yes — we survey and quote solid wall insulation in Barnet (EN5) and nearby Potters Bar, Borehamwood and Finchley, with a fixed written price before any work starts.