Communal areas only or the whole building?
A communal-areas-only survey covers the parts of a building shared by everyone: corridors, stair cores, lobbies, service risers, plant rooms, bin stores and roof spaces reached from common parts. In a block of flats this is usually where the Responsible Person's duties are focused, and it is where most shared services run.
A whole-building survey also includes the inside of individual flats, offices, wards or tenant areas. It is needed when compartment lines run through private areas, for example where a flat's walls form part of the protected corridor, or where services leave a riser and pass into each unit. It needs access to every unit, which takes the most planning.
Many clients start with communal areas, then extend to a sample of flats or units once the first findings show where problems are likely.
What does a visual, non-intrusive survey find?
A visual survey records everything that can be seen and reached without damaging the building. By arrangement we lift ceiling tiles, open access hatches, riser doors and service cupboards, and look into roof spaces and ceiling voids. Every observation is photographed, located and described, with a recommended remedy.
It finds unsealed and poorly sealed penetrations, gaps at the head of walls, damaged seals and missing fire stopping wherever the construction is exposed. What it cannot see is anything behind finished surfaces: inside boxed-in services, behind plasterboard linings or within sealed-up voids. Those limits are recorded in the report so nobody assumes an area was inspected when it was not.
Because nothing is opened up, there is little disruption, no making good and no need to disturb materials that might contain asbestos. It suits most buildings as a first survey and as a re-check after works.
What is a sampled intrusive survey?
A sampled intrusive survey opens up a representative sample of locations: a number of boxings, linings, flat entrance areas or sealed voids chosen to reflect the building's construction and history. The aim is to find out what is behind finished surfaces without opening up everything.
If the sample finds consistent problems, that is strong evidence the same issue exists elsewhere, and the Responsible Person can decide, with their Fire Risk Assessor, whether wider investigation is needed. If the sample is consistently sound, that is useful evidence too.
It needs more planning than a visual survey: agreement on exactly which locations will be opened, a check of the asbestos register for each one, arrangements for residents or occupants, and agreement on who makes good afterwards.
What is a fully intrusive survey?
A fully intrusive survey opens up construction wherever it is needed to inspect compartment lines in full. It gives the most complete picture and causes the most disruption: rooms may be out of use, finishes are removed and replaced, and occupants need to be moved or warned.
Some clients ask for a "Type 4"-style inspection. The term is used in fire risk assessment practice for blocks of flats to describe a destructive inspection of both common parts and flats. If that is what you have been asked to commission, tell us, and we will agree in writing the areas, the opening-up method, the asbestos checks and the making good before anything is touched.
Which type is right for your building?
There is no single answer, and we do not choose for you. As a general guide:
| Survey type | What is inspected | Disruption | Typical use |
|---|---|---|---|
| Visual, communal areas | Shared risers, corridors, stair cores, plant rooms and roof spaces, where access is provided | Low | A first survey, or a re-check after works |
| Visual, whole building | Communal areas plus the inside of flats, offices or tenant areas | Low, but needs access to every unit | Where compartment lines and services pass through private areas |
| Sampled intrusive | A representative sample of boxings, linings and sealed voids opened up | Medium; making good agreed in writing | Where visual findings or the building's history raise questions |
| Fully intrusive | Construction opened up wherever needed to inspect compartment lines in full | High; rooms may be out of use | Where the fire risk assessment or fire strategy calls for it |
- Visual, communal areas: a first look at shared risers, corridors and plant rooms, or a re-check after works.
- Visual, whole building: where services and compartment lines pass through private areas.
- Sampled intrusive: where a visual survey or the building's history raises questions about what is behind finished surfaces.
- Fully intrusive: where your fire risk assessment or fire strategy calls for it, or the sample findings justify it.
Your fire risk assessment is often the best starting point: it may already recommend a particular level of survey. See compartmentation surveys for how we carry out the work and what affects the cost of each type.
Why must the asbestos register be checked first?
Buildings constructed or refurbished before 2000 may contain asbestos, and it can be found in exactly the places compartmentation surveys look: ceiling voids, boxings, risers and around old services. Opening up any of these without knowing what is there could put surveyors and occupants at risk.
Before any intrusive work we check the asbestos register for every location to be opened. If the register does not cover an area, we do not open it up until that information is available.
Frequently asked questions
What is your standard compartmentation survey?
Visual and non-intrusive, covering everything that can be seen and reached where access is provided, including lifting ceiling tiles and opening hatches by arrangement.
Do you do intrusive surveys?
Only by prior written agreement setting out exactly what will be opened, and only after the asbestos register for those areas has been checked.
What is a Type 4-style inspection?
A term used in fire risk assessment practice for blocks of flats, describing a destructive inspection of common parts and flats. We can carry out intrusive work of that kind once the scope is agreed in writing.
Who makes good after opening up?
That is agreed in writing before work starts, so it is clear who reinstates each opening and to what standard.
Can we start with a visual survey and add intrusive work later?
Yes. Many clients do, using the visual findings to choose where a sample should be opened.
Will the report say which areas were not inspected?
Yes. Areas we could not access or see into are recorded, so the limits of the survey are clear.
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