Manhole / Inspection Chamber – cost per nr – 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.

Manhole — precast concrete chamber

per m² · supply & lay

£1,614 – £2,876 / nr

What is it

The construction of one precast concrete-ring man-entry manhole — a 1200 mm diameter chamber roughly 2.0 m deep to invert, set complete and priced per nr (each). A manhole is the access & junction chamber a drainage BoQ measures separately from the pipe runs. The rate carries the whole operation:

Excavated & based — the pit is machine-dug and an in-situ C20/25 concrete base and channel benching laid to the invert.
Ringed — precast concrete chamber rings set to depth on the base, joints bedded & sealed, reduced with a precast cover slab.
Covered — a Class D400 ductile cover & frame set to level, and the chamber backfilled & compacted.

Rate range

Low£1,614 – £2,080 / nr

Typical£1,867 – £2,407 / nr

High£2,231 – £2,876 / nr

Budget rate per m².

3 key cost drivers

Manhole depth & size

Depth to invert is the biggest driver: a deeper manhole needs more precast ring metres and a slower, supported excavation. Diameter (1050 mm minimum man-entry, 1200 mm default, larger for junctions) sizes the rings and cover slab. Both are key drivers of the per-nr rate.

Cover class & location

A trafficked carriageway needs a heavy Class D400 ductile cover (the priced default); a footway (B125) or garden (A15) takes a lighter, cheaper cover. Location also sets how much dig support, dewatering and reinstatement the pit needs. Described drivers, priced by swapping the cover and depth.

Location

London and the South East typically add around 20% to labour.

Estimator

Budget rate generator

£1,867 – £2,407 / nr

Covers the pit excavation, C20/25 base & benching, precast rings, cover slab, D400 cover & frame, backfill and O&P · excl. connecting drainage runs, disposal of arisings, support/dewatering & VAT

Exclusions

Lifting & material distribution — telehandler / forklift, hoist and site-distribution labour (an attendance, in main-contractor prelims)
The connecting drainage runs, disposal of surplus arisings, deep-dig support, dewatering & rock
Carriageway/pavement reinstatement above the cover, and any drainage below the invert
Scaffold supply (usually in preliminaries)
Preliminaries — main-contractor site set-up, management & welfare
VAT