External Wall Insulation (EWI) – cost per m² – UK 2026 Rate Guide

Budget rate for supply & lay · typical budget rate before your adjustments

Labour, plant, materials, outputs and waste — yours to edit, as an Excel. Three free.

Rates are UK national (non-London): central London and constrained urban sites typically run dearer — adjust the labour, plant and access lines in the build-up accordingly.

External wall insulation (EWI)

per m² · supply & lay

£107 – £212 / m²

What is it

The supply and installation of a full external wall insulation (EWI) system to an existing solid or masonry wall, priced per m² of insulated & rendered wall. This is the standard, mainstream EWI spec — a 100 mm graphite-EPS insulation board finished with a through-coloured silicone thin-coat render. A mineral-wool board system (fire-rated / breathable) is the dearer alternative. The system carries four operations:

Board fixed — 100 mm graphite-EPS boards bedded on adhesive and mechanically fixed with hammer anchors, off a levelled starter track.
Mesh & basecoat — a polymer-cement basecoat with alkali-resistant fibreglass mesh fully embedded, plus bead & corner reinforcement.
Topcoat — a through-coloured silicone thin-coat render applied and textured over a primer/key coat — the self-coloured weather finish.
Beads & details — starter track, bellcast, stop, corner and reveal beads, and primer to junctions and openings.

Rate range

Low£107 – £138 / m²

Typical£131 – £169 / m²

High£165 – £212 / m²

Budget rate per m².

3 key cost drivers

Wall complexity

Openings, reveals, cills and detailing mean more bead, cutting and reveal-boarding per m², slowing the gang; large open elevations install fastest. Labour is a big driver of this rate.

Board type & substrate

Graphite EPS is the mainstream, priced default; a mineral-wool (fire-rated / breathable) board is a dearer, heavier system that runs materially higher per m². A poor or uneven substrate needs prep and dubbing-out, using more adhesive and slowing the fix.

Supply & quantity

Merchant prices for the bought-in materials move with supplier, account and load size, and the published band already spans that range. Rates are UK non-London; London & the South East typically run dearer — adjust the build-up.

Estimator

Budget rate generator

£131 – £169 / m²

Covers the insulation board, adhesive, mesh, basecoat, silicone topcoat render, fixings & beads, the render gang and O&P · excl. scaffold, the wall behind, making good & VAT

Exclusions

Lifting & material distribution — telehandler / forklift, hoist and site-distribution labour (an attendance, in main-contractor prelims)
Scaffold / access — a separate rate (EWI almost always needs it)
The wall behind, substrate repairs, moving pipes/soil stacks/meter boxes, window-reveal making-good & VAT
Scaffold supply (usually in preliminaries)
Preliminaries — main-contractor site set-up, management & welfare
VAT