A practical checklist for housebuilders moving plot by plot through Part L 2026 compliance. Work through every box and the plot reaches completion with the documents building control and the warranty provider will ask for.
Design stage
☐ Standard house type drawings updated for FHS fabric, roof loading and array placement
☐ Plot-level orientation and shading assessment completed
☐ Solar PV array sized against the 40% ground-floor-area notional dwelling (or the shortfall addressed in the SAP design)
☐ Heat pump type, size and hot water cylinder specified (with gas boilers banned in new builds in practice, there is no fossil-fuel fallback)
☐ Ventilation strategy and any MVHR ductwork routed early
☐ Part S EV charge point location agreed
SAP 10.3 modelling
☐ Accredited on-construction energy assessor commissioned (through a scheme such as Elmhurst or Stroma)
☐ Design-stage SAP 10.3 calculation showing the Part L targets are met
☐ For plots with transitional protection, the applicable Part L edition confirmed
☐ Part O overheating assessment completed (simplified method or dynamic modelling)
☐ Plot-level variation captured (orientation, shading, party walls)
☐ Design-stage documents issued to building control
Building control submission
☐ Full plans application or building notice submitted
☐ Building control body agreed (local authority or registered building control approver)
☐ Plan check fee paid
☐ Pre-construction meeting held
☐ Plot register kept to track transitional and FHS plots
On-site delivery
☐ Fabric installed to the specified U-values, with site QA records
☐ Air permeability test on completion, result within the design value
☐ In-roof PV mounting fitted before tiling or slating
☐ Inverter and isolators positioned for safe access
☐ Heat pump and hot water cylinder commissioned
☐ Ventilation commissioned with measured airflows
☐ EV charger installed and tested
Sign-off
☐ MCS certificate issued for the solar PV
☐ Network operator notified (G98) or connection approved (G99)
☐ As-built SAP calculation and EPC issued
☐ Building control completion certificate issued
☐ Structural warranty provider notified and satisfied
☐ Buyer pack handed over, including the MCS certificate, user guide and monitoring login