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.
Cavity wall (brick & block)
per m² · supply & lay
£234 – £397 / m²
What is it
The supply and laying of a full cavity wall as one composite rate, priced per m² of wall face: a half-brick (102.5 mm) facing outer leaf in stretcher bond, a full-fill insulated cavity with wall ties, and a 100 mm block inner leaf — the standard external wall of a UK masonry building. The rate builds all three elements as one gang operation:
Outer leaf — standard machine-made facing bricks bedded in mortar to a half-brick stretcher-bond skin, gauged, plumbed and pointed as the work proceeds (~60 bricks per m²).
Insulated cavity & ties — 100 mm full-fill mineral-wool cavity batts built in against the inner leaf, with stainless wall ties at the specified centres tying the two leaves together.
Inner leaf — a 100 mm medium-density block skin (the representative inner leaf), laid in mortar to receive the internal finish.
Rate range by wall complexity
Simple£234 – £302 / m²
Standard£264 – £341 / m²
Complex£308 – £397 / m²
Budget rate per m².
3 key cost drivers
Wall complexity
Openings, returns, piers and reveals slow the gang and add cutting waste. It is a key driver of the rate.
Wall specification
The outer-leaf brick (standard wirecut vs handmade / engineered), the inner-leaf block and the cavity insulation (full-fill mineral wool vs partial-fill PIR) drive the material cost. This rate prices the standard commodity spec — a wirecut facing, a medium-density inner block and 100 mm full-fill mineral wool.
Location
London and the South East typically add around 20% to labour.
Estimator
Budget rate generator
£264 – £341 / m²
Covers the facing outer leaf, full-fill cavity insulation, ties, the block inner leaf, mortar, the laying gang and O&P · excl. prelims, scaffold & VAT
Exclusions
Lifting & material distribution — telehandler / forklift, hoist and site-distribution labour (an attendance, in main-contractor prelims)
Foundations, the DPC membrane, lintels, cavity trays, closers, weep vents & movement joints
Internal finishes (plaster / dry-lining), the roof & scaffold
Scaffold supply (usually in preliminaries)
Preliminaries — main-contractor site set-up, management & welfare