The £4,350 per plot figure
The government central case for the FHS uplift is approximately £4,350 per plot, per the FHS impact assessment[Future Homes Standard / Part L]. The figure varies by dwelling type (flats are typically lower per unit than detached houses) and by regional fabric-cost variation.
Part L 2025 interaction
FHS sits on top of the Part L 2025 uplift already in force. New permissions accommodate Part L compliance as a build-cost line; FHS adds the further uplift for the standard's full commencement.
Outline versus full applications
Outline permissions are determined against the regulation in force at reserved-matters approval, not at outline determination. This means schemes consented at outline before FHS commencement still carry the FHS cost at build-out.
Treatment in viability appraisal
FHS is a build-cost line, not an S106 obligation. It feeds the residual viability appraisal directly. Where FHS makes the scheme sub-viable at the policy-compliant tariff, the NPPF para 58 viability route applies; see /viability.