East of England
External Wall Insulation in Hertfordshire
EWI systems that insulate solid walls externally and finish them in a warranted render topcoat.
Hertfordshire property owners come to us for external wall insulation for one of two reasons: something has failed, or the house looks tired.
Most of what we see around Hertfordshire reflects the wider Hertfordshire pattern — Victorian and Edwardian housing, garden-city development and extensive modern commuter estates, and render refresh and colour change on well-maintained commuter housing. With a drier inland climate, specification matters more in this part of the country than a national price list suggests.
Local factor. Welwyn and letchworth garden-city stock carries design constraints that affect colour and finish choices more than technical performance.
Is external wall insulation right for a Hertfordshire property?
Choose EWI on solid-wall, no-fines or non-traditional construction where you want a genuine thermal upgrade rather than just a new finish.
That decision gets made at the survey, not on the phone. We will tell you plainly if a different system would serve the building better — including when a cheaper one would.
Guide price and specification
| Guide price | £135–£210 per m² |
|---|---|
| Applied thickness | 50-150mm insulation plus render system |
| Curing / drying | Staged, 7-10 days total |
| Guarantee | 25 years |
| Coverage | All of Hertfordshire — 10 towns and cities |
Indicative only, excluding scaffold, stripping and repairs. Try the guide-price tool for a range based on your property.
What is included
- 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
- Eaves and verge extensions
- Fire-rated mineral wool options
External Wall Insulation across Hertfordshire
External Wall Insulation in Hertfordshire
Tell us about the property and we will call you back to arrange a survey.
Other services in Hertfordshire
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 Hertfordshire — questions
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.
How long does a rendering job take?
A typical three-bedroom semi is usually one to two weeks on site including scaffold, preparation, application and finishing. Weather, wall condition and the system chosen all move that.
External Wall Insulation quotes across Hertfordshire
Free survey, honest advice on whether this is the right system, and a fixed written price.