Moisture & mould riskPerformance duties
Moisture and mould queries, checked against the build-up and its conditions.
A condensation, moisture or mould concern has been raised against a board, system or build-up — and the answer depends on conditions and assumptions nobody has written down yet.
The Bench reviews the evidence and the assumptions behind it — internal conditions, external exposure, build-up layers — and sets out in writing what the documents support and what remains unresolved.
ScopeEvidence review. Not certification, Building Control or design sign-off.
The questions that usually arrive with a moisture query
Will this build-up cause condensation?
Someone wants confidence that the proposed build-up manages moisture in the conditions it will actually experience.
Is this board suitable for a wet or humid area?
The product has moisture-related evidence, but it needs matching to the actual internal environment and use.
A moisture or mould issue has appeared — is the product to blame?
The real question is whether the use, conditions and build-up match what the product evidence assumed.
Do the environmental assumptions hold?
An assessment exists, but it was run for different internal or external conditions than the project's.
The paperwork behind a moisture 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:
- Product data sheets with moisture-related performance data
- Condensation or hygrothermal assessments, where they exist
- Build-up drawings, including membranes, cavities and layers
- A description of the internal conditions and intended use
- Installation guidance for the board or system
- The query as raised — the email, comment or site report
Where moisture evidence usually falls short
The assessment used default conditions, not project conditions
The calculation was run with standard assumptions that do not match the building's actual use or environment.
Board resistance is read as build-up safety
A moisture-resistant board is taken as proof the whole build-up manages moisture — they are different questions.
The assessed and installed build-ups differ
A membrane, cavity or vapour control layer in the assessment is missing, moved or swapped in the installed construction.
The environment has changed
Occupancy, ventilation or use is different from what the evidence assumed — and the assumption was never revisited.
The moisture pathways every wall must manage
A conceptual figure from the published review. It explains the routes moisture takes; it is not a condensation or hygrothermal assessment of any build-up.
Fig. 1Cavity vs No Cavity? · External Issue 02 · August 2026 · conceptual figure
A written moisture evidence position you can use
The Bench reviews the moisture-related evidence against the actual build-up and the stated conditions, and puts the position in writing.
- Review the moisture and condensation evidence against the actual build-up and conditions
- Separate product properties from build-up behaviour — and say which the question needs
- Flag the assumptions doing the heavy lifting in any existing assessment
- Identify what evidence or assessment may be needed before the question can be answered with confidence
- Provide a written note you can use with the project team, client or consultant
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 moisture and mould risk in particular, the limits matter:
Not part of the review
- Hygrothermal or condensation design responsibility
- Certification, testing or product approval
- Building Control or other statutory sign-off
- A guarantee that a build-up will not experience moisture or mould problems
Those decisions stay with the competent person or organisation appointed on the project. Our written review supports them; it does not replace them.
Moisture or mould query holding up the job?
Send the question, the build-up detail, the conditions and the documents you already have. No charge to submit an enquiry — we quote before any written work starts.
Not sure where your question sits? Find your route ›
What helps us start
- The question, as it was put to you
- What the product or build-up is, and where it is going
- The documents you already have — data sheets, reports, certificates, drawings
- Any comment from Building Control, the designer or the client
- When you need an answer
You do not need a complete set to get in touch — send what you have.