Part L Building Regulations Compliance
Part L2 compliance modelling for new-build and major refurbishment, from RIBA Stage 2 to sign-off.
What it is
Statutory compliance with Approved Document L of the Building Regulations, demonstrated through SBEM or DSM modelling of the Target Emission Rate (TER) and Building Emission Rate (BER), with as-built BREL reporting at completion.
Who needs it
Architects, developers, contractors, and design teams delivering new non-domestic buildings or major refurbishments in England.
When it's required
At planning, at Building Control submission, and at completion. Early-stage modelling avoids expensive redesign at Stage 4.
What we provide
- [01]Notional vs proposed building modelling at RIBA Stages 2–4
- [02]SBEM and DSM Part L2 calculations
- [03]Fabric, glazing and services optioneering
- [04]As-built BREL reporting
- [05]Building Control liaison and sign-off support
Related services
How this compares
Side-by-side breakdowns of the standards and routes most often confused with this service.
SBEM vs DSM
SBEM is a simplified monthly calculation suitable for standard buildings; DSM simulates the building hour by hour and is required where systems are too complex for SBEM to represent.
TM54 vs Part L
Part L models only regulated energy to prove regulatory compliance; TM54 predicts total in-use energy including everything the occupier will actually pay for.
Energy Statement vs Part L
An Energy and Sustainability Statement satisfies planning policy before consent; Part L calculations satisfy building regulations before and after construction.
Common questions
[01]Who provides Part L and SBEM calculations?+
Braithwaite Energy provides Part L2 compliance modelling and SBEM calculations across the UK, working with architects and developers from RIBA Stage 2 to Building Control sign-off.
[02]What is an SBEM calculation for new buildings?+
SBEM, the Simplified Building Energy Model, is the government's approved methodology for calculating the monthly energy use and carbon emissions of a non-domestic building from its floor area, fabric, conditioning, hot water and lighting. For new buildings it is used to demonstrate compliance with Part L of the Building Regulations at design stage and again as built.
[03]When do I need Part L design-stage and as-built calculations?+
A design-stage BRUKL is required before work starts to show the proposed building complies, and an as-built BRUKL plus the new-build EPC is required at completion to reflect what was actually installed. Building control will not sign off without the as-built submission, so late design changes must be fed back into the model.
[04]What changed under the 2021 Part L uplift?+
The 2021 edition tightened target emission rates substantially for non-domestic buildings, introduced a primary energy target alongside carbon, brought in tougher fabric and services standards, and added photographic evidence requirements for as-built compliance. It is a staging post towards the Future Buildings Standard, so schemes designed to the old edition rarely pass unchanged.
[05]How early should an energy consultant join a design team?+
Ideally at RIBA Stage 2, while orientation, glazing ratios, fabric strategy and plant selection are still open. Energy advice introduced after Stage 4 can usually only add cost, because the cheap carbon savings are locked into decisions already made.
Begin a project enquiry.
Same team on services design and compliance modelling. UK-wide, from London and York.