Service · Intrusive investigations
Intrusive investigations: see what is really behind the façade.
Drawings show what was designed. Opening-up shows what was built. We plan, manage and record targeted intrusive investigations that give you definitive evidence, with as little disruption as possible.
Why opening-up matters
The parts of an external wall that matter most for fire safety and long-term performance are hidden once a building is complete: insulation, sheathing boards, cavity barriers, fire-stopping, membranes and fixings. Where construction records are incomplete or inconsistent, a desk review can only go so far. Targeted intrusive investigations confirm the as-built construction so decisions rest on evidence rather than assumption.
When you need one
- To support a PAS 9980 FRAEW or EWS1 where records do not give a definitive answer.
- To confirm the wall types on a building and reconcile them against the design drawings.
- To investigate suspected defects, such as missing cavity barriers, water ingress or failed fixings.
- Before remediation, so the scope and cost are based on what is actually there.
How we carry them out
We start with the information: drawings, specifications, material schedules and any construction-phase quality records. From that we choose a small number of investigation locations that will answer the most questions, taking account of each wall type, access and residents.
Openings can be made from outside, using suitable access, or from inside occupied apartments where that causes less disruption. We manage the work end to end with our in-house contractors, record each layer of the wall with photographs and measurements, and leave every location ready to be made good.
What you receive
- A location-by-location record of the as-built wall build-up and materials.
- A reconciliation against the design and construction information, highlighting any differences.
- Clear conclusions and, where needed, recommendations for further work.
Recent investigations
As-built wall types confirmed on two occupied build-to-rent towers (429 homes) through targeted openings from inside apartments, reconciled against more than 6,000 pages of design information.
One day of targeted opening-up, combined with construction records, to reach a definitive low-risk FRAEW conclusion and an EWS1 A1.
One Crown Place, City of London
A 48-hour intrusive survey on a 100 m+ tower, as part of a peer-reviewed FRAEW delivered in five working days.
Frequently asked questions
How many openings does an intrusive investigation need?
It depends on the number of wall types and the quality of the records. We aim for the smallest number of well-chosen locations that will give a definitive answer, rather than opening up for its own sake.
Can investigations be carried out with residents in occupation?
Yes. Openings can often be made from inside apartments, which avoids external access and keeps disruption to a minimum. Each location is left ready to be made good.
Do you use your own contractors?
Yes. We manage intrusive investigations end to end using in-house contractors, so opening-up, recording and making good are coordinated by one team.
Are intrusive investigations needed for every FRAEW?
No. Some buildings have records good enough for a desk-based conclusion. Opening-up is recommended where the evidence is incomplete or conflicting.
Related services and case studies
Talk to us
Need to know what is behind your cladding?
Tell us about the building and what you need to know. We aim to respond within one working day.