Fast, independent U-value calculations for extensions, loft conversions, new builds and refurbishments — prepared by a RICS Chartered Building Surveyor with 45 years of Building Control and Building Standards experience. Desktop service, UK-wide, no site visit required.
RICS Chartered Building Surveyor | Elmhurst Energy Accredited Assessor | 45 Years' Building Standards Experience
Many insulation manufacturers offer free U-value calculations. They're a reasonable starting point, but they come with limits worth knowing about before you submit anything to Building Control.
A manufacturer's calculator is built to specify that manufacturer's product. Our calculations are independent and product-neutral — we tell you what the build-up actually achieves, not what sells the most insulation.
A U-value on its own doesn't tell you whether a build-up is at risk of interstitial condensation. We check this as standard, which free product-selection tools typically don't.
If a build-up falls short of target, you get an explanation of why and what would close the gap — not just a number and a dead end.
Prepared by a Chartered Building Surveyor with 45 years in Building Control and Building Standards, so the output is written with Building Control submission in mind from the start.
A straightforward desktop process. No site visit, no back-and-forth if you send everything up front.
Email the construction details for each element — wall, roof or floor — including layer thicknesses and materials, plus any drawings you have.
Each element is calculated to BS EN ISO 6946 / BR 443 methodology, with a condensation risk check included as standard.
A clear, written calculation for each element, suitable to submit to Building Control or pass on to your architect or contractor.
If a build-up doesn't meet target, we'll explain what would need to change — with further advisory support available if you want it.
One simple, fixed fee. No hidden extras.
An "element" is a distinct wall, roof or floor build-up — a typical extension with one wall type, one roof type and one floor type is usually three elements. Discounts are available for developments with repeated house types. Get in touch for an exact quote.
An element is one distinct type of external wall, roof or floor construction. If your extension has a single wall build-up, a single roof build-up and a single floor build-up, that's three elements. A more complex design with, say, two different wall constructions would be four.
No. This is a desktop calculation based on the construction details and drawings you provide, so it can be carried out anywhere in the UK without a site visit.
Yes. The calculation is prepared with submission in mind, and is backed by RICS chartered status and Building Control experience.
For each element: the layers of the construction in order, their thicknesses, and the materials or products used (including insulation type and thickness). Drawings help but aren't essential if you can describe the build-up clearly.
We'll tell you clearly, and explain what change would close the gap — for example, additional insulation thickness or a different product. Further advice beyond that is available through our Building Regulations advisory service.
Yes, UK-wide. The underlying calculation method is the same across the UK; target values differ by nation and by the applicable edition of the regulations, which we account for based on where the property is.
Yes — U-value calculations are one part of what ThermaCheck Ltd offers. Visit our main site for SAP assessments, EPCs, Planning Energy Statements and Building Standards consultancy.
Email your construction details and drawings and we'll come back to you with a fixed-price quote and likely turnaround.
Email: info@thermacheck.co.uk
The email link opens a pre-filled message so you can just add your details — property address, which elements you need calculated, a brief description of the construction, and your timescale.
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