Change of use · Part L1B
If your project creates a new dwelling via change of use (e.g. barn conversion, or creating/altering flats within an existing building), your Building Regulations application requires a Part L1B SAP calculation. We’ll guide you through practical, cost-effective compliance from design to completion.
Related: SAP / EPC overview · PSI & U-Value calculations · Water Efficiency (Part G) · Air Tightness Testing · Mechanical Ventilation Testing
Why EAC South West
We simplify Part L1B for change-of-use projects and keep costs under control.
Deep experience with conversions — from barns to multi-unit changes of use.
We assess from architects’ drawings and product specs to model your conversion accurately.
We never leave you with a fail — pragmatic, affordable adjustments to pass.
Process
We review plans and construction specs to identify the most efficient route to compliance.
We balance upgrades to the existing fabric, new elements, openings, and services to meet Part L1B.
We issue a draft with clear options if tweaks are needed — always aiming for the most cost-effective pass.
At completion we finalise SAP and lodge the as-built SAP report and EPC with Landmark.
Checklist
Send drawings/specs electronically or by post — we’ll take it from there.
Send your drawings and spec — we’ll deliver a clear, compliant SAP package fast.