Harrow, Greater London
External Wall Insulation in Harrow
EWI systems that insulate solid walls externally and finish them in a warranted render topcoat.
Harrow property owners come to us for external wall insulation for one of two reasons: something has failed, or the house looks tired.
Greater London is characterised by Victorian and Edwardian terraces, interwar suburban semis and high-density modern development, with solid-wall Victorian terraces, party-wall constraints and heavy atmospheric soiling the recurring theme on the properties we survey.
Local conditions bring a drier urban climate with a pronounced heat-island effect, and that has a direct bearing on which systems are worth specifying. Atmospheric pollution soils render faster in london than anywhere else in the uk, which is why self-cleaning silicone finishes are specified so heavily here.
When external wall insulation is the right call. Choose EWI on solid-wall, no-fines or non-traditional construction where you want a genuine thermal upgrade rather than just a new finish.
Guide price in Harrow
| Guide price | £135–£210 per m² |
|---|---|
| Applied thickness | 50-150mm insulation plus render system |
| Guarantee | 25 years |
Indicative only. The guide-price tool gives a range for your property; the survey gives the fixed price.
What the job includes
- EPS, mineral wool and phenolic boards
- 50mm to 150mm thicknesses
- Mechanical and adhesive fixing
- Reinforced basecoat with mesh
- Silicone or acrylic topcoat
- Window and door reveal detailing
We will survey the property, tell you what the walls actually need, and put it in writing with a fixed price.
Also covering near Harrow
External Wall Insulation in Harrow
Tell us about the property and we will call you back to arrange a survey.
What happens next
Four steps from enquiry to finished wall
Free survey
We visit, test the substrate, measure up and identify what caused any existing failure.
Written quote
An itemised fixed price with the system named, materials specified and scaffold included.
Booked in
An agreed start date, scaffold arranged, and a clear run of days set aside for your job.
Finished and guaranteed
Site cleared, scaffold struck, guarantee documents and system warranty issued.
FAQs
External Wall Insulation in Harrow
How long before I can paint new render?
Through-coloured systems need no painting at all. Sand and cement should cure for around 28 days before masonry paint goes anywhere near it.
Do you take a deposit?
For most domestic jobs we take a deposit to cover materials and scaffold, with the balance on completion. Terms are set out clearly in the written quote.
Can you match my existing render?
Usually, yes. We colour and texture match as closely as we can, though weathered render never matches a fresh batch exactly — we will be honest about how visible a patch will be.
Will EWI make my house look different?
The walls become 70-200mm thicker, so reveals get deeper and the eaves usually need extending. Done properly it looks intentional; done cheaply it looks like a box.
Can EWI cause damp?
Correctly specified it reduces damp risk by keeping the wall warm. Problems come from poor detailing at reveals, sills and penetrations, or from using a non-breathable system on a wall that needed one.
Free survey in Harrow
We will confirm whether external wall insulation suits your walls before quoting a price.