Abnormal costs on school construction

Typical abnormal-cost categories on UK school schemes (asbestos, RAAC, contaminated land, demolitions, plant relocation) with £ ranges and when to raise the 5% default allowance.

What counts as an abnormal

Abnormal costs are works above and beyond what the BCIS rate assumes , anything specific to your site that wouldn't feature on a notional new-build plot. The default allowance in this calculator is 5% of works; on confirmed-RAAC or asbestos-heavy sites, raise it.

Typical ranges

Asbestos removal: £15-65/m² of affected floor area on a 1960s-1970s build[LGA Bench.].
RAAC mitigation (props, scaffolding, temporary teaching): around £80-220k per affected block, before any permanent rebuild[RAAC].
RAAC permanent replacement: typically subsumed into an SRP rebuild at the standard £/m²[SRP].
Contaminated land remediation: £40-200/m² of disturbed area, depending on category and disposal route.
Demolitions of a single-storey block: £80-120/m² of GIFA demolished.
Plant and IT relocation during a live-site refurb: 1.5-4% of works.
Temporary classrooms (decant): £550-900 per pupil per term.

How abnormals are treated under CIF vs SRP

CIF[CIF] expects abnormals to be evidenced by a condition survey and itemised in the business case; the 10% fee cap applies to the works total including reasonable abnormals. SRP[SRP] absorbs RAAC and other condition-driven abnormals into the standard scheme cost when the project is delivered via the standard design. NAO January 2025[NAO] highlighted that abnormals are one of the largest drivers of schemes coming in above benchmark.

See RAAC remediation for the deadline and funding route, or whole-school refurbishment for an end-to-end refurb worked example.