Evidence area
Thermal claims and U-values, checked against the build-up actually installed.
A declared thermal value is being relied on — but the build-up, thickness or substrate on the project is not necessarily the one behind the number.
The Bench reviews whether declared values, U-value calculations and thermal claims match the actual build-up and the project requirement, and puts the position in writing.
Independent evidence review. Not certification, Building Control or design sign-off.
The questions that usually arrive with a thermal query
Does the declared value apply to this product and thickness?
A lambda or R-value is being quoted, and someone wants confirmation it belongs to the product, thickness and version actually specified.
Does the U-value calculation match the drawing?
A calculation exists, but the build-up it describes needs checking against the detail being drawn or installed.
Can this claim be used to show compliance?
A thermal claim is being relied on for a target U-value or specification clause, and the evidence behind it needs to stack up.
Two products claim the same performance — do they?
A substitution or comparison is on the table, and the declared values need reading against what each document actually covers.
Build-up items commonly checked
The paperwork behind a thermal question
Every enquiry is different, and you do not need a complete set before getting in touch — send what you have. These are the documents that usually matter:
- Declarations of performance and data sheets with declared thermal values
- U-value calculations, where they exist
- Build-up drawings with layer thicknesses
- Substrate and fixing details that affect thermal bridging
- The project requirement — the target U-value or specification clause
- The question as raised — the email or comment from the designer, assessor or client
Where thermal evidence usually falls short
The calculation describes a different build-up
The U-value calculation was run for a build-up that differs from the drawing in layers, thicknesses or materials.
The declared value belongs to a different product
The figure quoted relates to a different thickness, density or version of the product than the one specified.
Bridging and fixings are ignored
Fixings, frames and repeating bridges change the result, but the claim being quoted does not account for them.
A headline claim is quoted without its conditions
Declared values come with conditions attached, and the conditions are doing more work than anyone has checked.
A written thermal evidence position you can use
The Bench reviews the thermal evidence against the actual build-up and the project requirement, and puts the position in writing.
- Check declared values against the actual product, thickness and version specified
- Compare U-value calculation inputs with the drawn or installed build-up
- Flag mismatches, missing inputs and unsupported assumptions
- Set out what evidence would be needed to support the project requirement
- Provide a written summary you can use with the designer, assessor or project team
The output is written — a review note, clarification note, gap register or evidence summary you can use with the project team. We quote before any written work starts.
Clear about the limits of the review
The Bench reviews evidence and gives written guidance. For thermal performance in particular, the limits matter:
- Acting as the project's thermal designer or energy assessor
- Certification, testing or product approval
- Building Control or other statutory sign-off
- Design responsibility for the build-up or its compliance route
Those decisions remain with the appointed competent person or organisation for the project. Our written review is there to support them, not replace them.
Product knowledge that may relate to this evidence area
Where a product question sits behind this evidence area, the product knowledge pages set out the typical questions and the evidence commonly reviewed:
Product logos identify the product areas our evidence records cover. They do not imply certification, approval, endorsement or guaranteed acceptance of any product or build-up.
Thermal claim that needs checking against the real build-up?
Send the question, the build-up detail, the target requirement and the documents you already have. No charge to submit an enquiry — we quote before any written work starts.