BRUKL Calculations for New Build Commercial Properties in London
Demonstrating Part L compliance for building control sign-off. Design stage consultancy through to as-built certification, handled by our dedicated in-house technical team.
- Since 2007
- ~7% UK Market Share
- 4.8/5 Trustpilot(1,700+ Reviews)
- Directly Employed Assessors
What Are BRUKL Calculations?
BRUKL stands for Building Regulations UK Part L. A BRUKL report is the output document from SBEM (Simplified Building Energy Model) calculations, and is required for all new build commercial properties as part of the building control sign-off process.
The BRUKL report demonstrates that your new commercial building meets the energy efficiency requirements set out in Part L2A of the Building Regulations (or Part L2B for conversions and changes of use). Without a compliant BRUKL report, building control cannot sign off your project.
Alongside the BRUKL report, a non-domestic EPC is also produced for the new building.
Not sure if you need a BRUKL?
Use our interactive Part L flowchart to find out which energy calculations your project requires — whether it’s a new build, extension, conversion, or renovation.
Use our interactive Part L guide →Our Approach
Design Stage Calculations
Ideally, SBEM calculations should first be carried out at design stage, before construction begins. This allows us to assess whether the proposed design will meet Part L targets and, if not, recommend changes while they’re still easy and cost-effective to implement.
At design stage, exact product specifications may not yet be finalised. We can work with default values and calculate the maximum U-values your building fabric can have while still achieving compliance. This gives you and your design team clear parameters to work within.
As-Built Calculations
Once construction is complete, as-built calculations are carried out using the precise materials, systems, and specifications actually used. This produces the final BRUKL compliance report and the building’s EPC.
If we carried out your design stage calculations, the as-built work is produced at a reduced fee since much of the modelling is already in place.
If design stage calculations weren’t carried out and the building isn’t meeting compliance targets, we’ll work with you to find pragmatic and cost-effective solutions. We’ll test different scenarios to identify the easiest way to achieve a pass — we provide three alternative scenarios at no extra cost, with further options quoted as needed.
Why This Work Needs a Specialist Team
BRUKL calculations for commercial buildings are significantly more complex than domestic SAP calculations. A large commercial building might contain dozens of distinct zones, multiple HVAC systems, complex lighting designs, and mixed-use areas — all of which need to be accurately modelled in the SBEM software.
This is why we don’t leave this work to a single assessor working alone. Our dedicated in-house technical team handles the SBEM modelling for all commercial new build projects using DesignBuilder — the market-leading 3D building energy modelling platform. Unlike the free iSBEM tool, DesignBuilder enables our team to build a detailed 3D model of even the most complex building designs, test multiple compliance scenarios rapidly, and produce the BRUKL output documents with confidence. They work with this software daily and have produced calculations for a wide range of building types across the UK — from straightforward office fit-outs to large, multi-zone developments.
Faster turnaround
Typically under 5 working days once we have all the required information
Fewer errors
Experienced specialists working in a controlled environment
Better support
If building control raises queries, our technical team can respond directly
Practical advice
When a building isn't meeting targets, we can quickly model alternative approaches
What We Need From You
At Design Stage
- Architectural drawings (plans, elevations, sections)
- Building fabric specifications (or proposed specifications)
- Proposed HVAC system details
- Lighting design information (if available)
- Intended building use / activity zones
At As-Built Stage
- Final construction drawings (if different from design)
- Precise make and model of materials used
- Installed HVAC system specifications
- As-installed lighting details
- Any air tightness test results
No site visit is required — BRUKL calculations are a desk-based exercise completed using your drawings and specifications.
Failing to Meet Targets?
If your building isn’t passing Part L at either design or as-built stage, don’t panic. This is where our experience is most valuable.
We’ll model different scenarios to find the most practical route to compliance. This might involve adjusting insulation specifications, upgrading lighting, changing the ventilation strategy, or a combination of measures. We focus on finding solutions that are achievable and proportionate, not theoretical ideals that would require a redesign.
Our track record of working through compliance issues with developers means we understand the commercial pressures you’re facing and the need for pragmatic solutions.
Get Your BRUKL Quote
Tell us about your project and we'll provide a clear quote. We're happy to discuss your requirements and advise on the best approach for your timeline.