Pre-manufactured value

Pre-manufactured value (PMV) is a measure of the extent of offsite construction used on a project.

A project that is predominantly of traditional construction will have a low PMV, whereas a modular construction project would be likely to have a high PMV.

PMV can be calculated based on aspects of the project such as quantity of material manufactured offsite, percentage by volume of precast components and so on. The Department for Education defines PMV as (materials + offsite labour) / (materials + offsite labour + on site labour). Quantitative approaches such as this require that data is available in a suitable format and in sufficient detail to allow comprehensive calculations to be undertaken.

Alternatively a more qualitative approach can be adopted, describing PMV as high, medium or low.

Ref Methodology for quantifying the benefits of offsite construction, Tercia Jansen van Vuuren, CIRIA C792, 2020.

NB DfMA Overlay to the RIBA Plan of Work, Mainstreaming Design for Manufacture and Assembly in Construction, 2nd Edition, published by the RIBA in 2021, defines pre-manufactured value (PMV) as: ‘A proxy measure of project efficiency calculated as the project’s gross capital cost less the cost of prelims (site overheads) and site labour, divided by the gross capital cost, expressed as a percentage. The business-as-usual benchmark is 40%; anything higher has more of its operations conducted off site.’

PAS 8700:2025, Modern methods of construction for new build residential properties – Specification, Draft v 3.9, published by bsi in 2024, states: ‘The business-as-usual benchmark is 40%; anything higher has more of its operations conducted off site. Although not true in all cases, a higher percentage can lead to a more efficient – and therefore better value – project. Used judiciously in combination with other tools, for example, the Value toolkit, the measure is a useful way of framing project ambitions and monitoring progress.’

Offsite residential construction, Glossary of terms, published by Buildoffsite in 2018, states: ‘Smart construction places great emphasis on work carried out away from the site, known as pre-manufactured value. This results in a major improvement in the efficiency of the construction process, predictability of performance and outcomes, increased speed and greater certainty of project timetable and of project completion.’

[edit] Related articles on Designing Buildings

• British post-war mass housing.
• Design for deconstruction.
• Design for Manufacture and Assembly (DfMA).
• Modern methods of construction.
• Off site, on track.
• Off-site construction.
• Off-site prefabrication of buildings: A guide to connection choices.
• Prefabrication.
• Volumetric.