External wall insulation cost (UK 2026)

External wall insulation cost (UK 2026). The published installed range in 2026 is £110 to £180 per m² installed (DESNZ Domestic Cost Assumptions; insulated render systems publishers), or £14,000 to £22,000 on a typical 95 m² 1930s solid-wall semi. Both ends of that range are stated rather than collapsed to a midpoint, because the spread reflects real differences in scope, access and grant eligibility rather than installer mark-up.

• Material system: mineral wool, EPS or wood-fibre, with the wood-fibre option carrying a 15 to 25 percent uplift.
• Render finish: silicone vs acrylic; thin coat vs heavy.
• Detailing: window reveals, eaves, plinth and ground-line are roughly a quarter of the total labour.
• Scaffold: a typical semi will carry £1,200 to £2,500 of scaffold; terrace mid-positions are higher per house due to shared access.
• ECO4 eligibility for low-income households can strip the whole layer at LA Flex.

Sequence after a full RdSAP and condition survey under PAS 2035. Path B or C depending on archetype.

EWI on a solid-wall Victorian terrace is often the right thermal answer but the wrong planning answer; conservation areas and Article 4 directions need a Designer involved.