Costs: Off-site manufactures | Features

Cost comparisons
The following table is based on OSM components for housing, schools, healthcare and offices compared with traditional construction.
Component or assembly	Off–site manufacture costs (£)	On-site installation costs (£)	Comments
Pre-assembled 600 kW boiler system	35,000	39,000	Includes boiler, pressurisation unit, pumps, valves and controls
Roof-mounted plant room — heating (2 x 150 kW boilers)	99,000	95,000	Includes enclosure, associated and chiller plant (200 kW) pipework, insulation, pumps, pressurisation unit, condenser, controls. Note where cranage is available on site, the differential is decreased
Prefabricated power cabling system	15 £/m2	23 £/m2	For office (>5000 m2) refurbishment. Power supply to luminaires and air conditioning system
Bedroom modules fully furnished with en–suite bathroom	11,000	10,000	Bathroom includes bath, basin and WC
Kitchen modules fully fitted	14,000	12,500	Kitchen units and space requirements above minimum social housing standards
Modular dwelling units	550 £/m2	550 £/m2	External envelope and foundations are excluded
Table notes
Costs are indicative and are for labour and materials relating directly to the prefabricated units. Excluded are associated builder’s work; overheads; profit; preliminaries; professional fees; contingencies; tax allowances; VAT.
General cost benefits from reduced construction times have not been evaluated.