External cork insulation · UK installer
External cork insulation that insulates, waterproofs and refinishes in one pass.
A 3–6 mm sprayed cork coating applied to the outside of your walls. Up to 30% better U-value, Class 1 vapour-permeable, fire-rated B-s1, and a third of the cost of traditional EWI.
Why external cork insulation
Insulation, weatherproofing and finish — in a single 3–6 mm coat.
Traditional external wall insulation adds bulk, cost and disruption. Sprayed external cork bonds directly to the existing façade with no scaffolding scars and no need to strip the wall back. The result is a seamless, monolithic skin that cuts heat loss, sheds wind-driven rain, and gives the building a clean finished surface in one application.
Cork is naturally elastic, so the coating flexes with the building rather than cracking like sand-and-cement render. It bridges hairline cracks, resists impact, and stays colour-stable under UK weather. That's why we back it with a 25-year warranty and a service life of 40+ years.
Where it's used
Solid walls, cavity walls, render, timber, uPVC.
External cork insulation is suitable for almost any vertical substrate found on a UK building — pre-1920s solid brick, post-war cavity construction, existing render in any condition, pebble-dash, timber cladding, even uPVC fascias and weatherboards.
Common applications include solid-wall Victorian and Edwardian homes, tired pebble-dash and roughcast façades, EPC upgrades on rental stock, refurbishing failed render, and commercial retrofit projects where heritage or planning constraints rule out conventional EWI.
What you get
Breathable, fire-safe, carbon-negative.
Up to 30% better U-value
Independent testing on solid walls. Most clients see a clear difference in the first winter.
Class 1 vapour-permeable
Sheds rain, lets vapour out — no trapped moisture, no interstitial condensation.
Fire-rated B-s1, d0
Tested to EN 13501. Suitable for domestic, commercial and over-11m where compliant.
40+ colours, seamless finish
Pigmented coloured cork or matched to RAL, BS or Pantone. No visible seams or panel joints.
40+ year service life
Manufacturer-backed 25-year warranty. No repaint cycle, no maintenance bills.
Carbon-negative material
Cork bark is hand-stripped without felling. Harvested oaks store up to 5× more CO₂.
External cork insulation FAQs
What people ask before booking.
- What is external cork insulation?
- External cork insulation is a sprayed, breathable thermal coating applied to the outside of walls. Ours is a 3–6 mm cork-based system that bonds to brick, render, pebble-dash, timber and uPVC — insulating, waterproofing and refinishing the façade in one pass.
- How does external cork insulation compare to traditional EWI?
- External wall insulation (EWI) typically adds 100–150 mm of foam board, scaffolding, mesh and render — £8k–£22k and visible bulk that often falls foul of conservation rules. Sprayed external cork is roughly a third of the cost, only 3–6 mm thick, preserves architectural detail and carries a 25-year warranty.
- Will external cork insulation stop damp?
- Yes — and crucially without trapping it. The coating is Class 1 vapour-permeable, so wind-driven rain is shed from the surface while moisture vapour from inside the building can still escape. That eliminates the interstitial condensation that often degrades foam-based EWI on solid walls.
- How long does external cork insulation last?
- Engineered for a 40+ year service life with no repainting. Independent UV and weathering tests show negligible colour change after a decade. Backed by a 25-year manufacturer warranty.
- Is external cork insulation suitable for listed buildings?
- Often yes — because it's breathable, only millimetres thick, and reversible compared to EWI. We routinely deliver schemes signed off by conservation officers on pre-1920s solid-wall properties.
- What does external cork insulation cost?
- Most domestic projects fall between £45 and £85 per m² fully installed, depending on substrate condition, access and colour. We confirm pricing after a free site survey.