LearnInvestigations

One question. All the evidence. Limits stated.

An investigation takes a question the industry argues about and puts it to the evidence — structurally able to conclude in any direction, with no conclusion pre-approved.

The question is fixed first. The evidence is assembled and weighted. Every conclusion uses calibrated language — SUPPORTED through CONTRADICTED, with stated confidence — and where the evidence runs out, INSUFFICIENT EVIDENCE is recorded as a finding, not papered over.

01The register

Completed investigations

Cavity vs No Cavity?

External Wall Design in a Changing UK Climate

Under what conditions can cavity, partially cavity-based and cavity-free external wall systems provide safe, durable and resilient building-envelope performance — and what evidence is required to demonstrate those functions over the intended service life?

A completed 43-page evidence review — External Wall Design in a Changing UK Climate — examining regulation, warranty standards, official fire investigations, peer-reviewed building physics, international field records and UK climate projections. Principal findings carried with the report's own verdicts; areas the evidence does not reach recorded honestly as INSUFFICIENT EVIDENCE.

Investigation 001 · External Issue 02 · August 2026
Lead researcher and report author: Luke Smith · Briefing film published on YouTube; full written report released and available on the investigation page.

Read the investigation ›

The register continues as questions complete. Investigations take as long as the evidence takes — no schedule is promised, and nothing publishes before its evidence is ready.

02Where they come from

Investigations grow out of real enquiries.

When the same question keeps arriving underneath different projects — argued in absolutes, decided on assumptions — it becomes a candidate for the full treatment. The evidence areas map where those questions cluster; an investigation is what happens when one of them is worked through to the end.

Ask The Bench

Sitting on a question that deserves this treatment?

Send the question, the project detail and the documents you already have. No charge to submit — we quote before any written work starts.

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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.