What’s required, and when
Building Control requires SAP calculations at two stages of every new dwelling:
Design stage — before work starts, the SAP calculation shows how the proposed dwelling will comply with Part L. We model the dwelling from your drawings and specification against the notional target dwelling; it passes when CO₂ emissions (DER) and fabric energy efficiency (DFEE) are no worse than the targets.
As-built stage — once complete, a new set of SAP calculations confirms that what was actually built complies, incorporating any spec changes made during construction plus the details needed for EPC lodgement: full postal address, make and model of heating system, and the air test certificate. We then lodge the EPC based on the as-built spec — Building Control can’t sign off without it.
How it works
It’s a desktop study — no site visit or survey. Send us plans, sections and elevations (PDF, DWG or paper) plus a construction and services specification. We build a ‘base’ calculation, and if it fails we don’t just report that: we model scenarios and recommend the most cost-effective route to a pass, based on what’s practical for your build. Calculated junction Ψ-values (via our ΨMonkey calculator) are often the cheapest fix of all.
We work with you throughout the build and are on call whenever you need guidance.
In a hurry?
Ask about ASAP, our fast-track priority SAP service for tight deadlines.