Compartmentation is the part of a building’s fire strategy that nobody sees and everybody relies on. It only works if every wall runs tight to the slab soffit, every service penetration is sealed with a tested system, and every cavity barrier sits where the drawing said it would. One unsealed riser penetration undoes the wall it passes through.
ATOL Construction surveys, installs and certifies passive fire protection across London and the South East. We work for main contractors, managing agents, housing providers and building owners, and we hold third-party certification through the BM TRADA Q-Mark scheme and NAPFIS membership.
Compartmentation surveys
Most remedial programmes start in the wrong place: a quote for sealing penetrations before anyone has established where the compartment lines actually are. We survey first.
A compartmentation survey from ATOL establishes what the compartmentation strategy was meant to be, what is actually built, and what it will take to close the gap. You get:
- Compartment line drawings marked up against the as-built layout, so you can see which walls and floors are doing fire-separating work.
- A defect schedule, item by item, with a photograph, location reference, the standard it fails against and the system needed to correct it.
- Priority ratings, so you can spend on the breaches that matter this quarter rather than treating a plant room riser and a decorative bulkhead as the same problem.
- A costed remedial programme, priced by us or given to you to tender, whichever you prefer.
Surveys can be non-destructive, or opening-up where ceilings and risers need to come down to see the junction. We will tell you honestly which you need. A non-destructive survey of a building with suspended ceilings and boxed risers will miss things, and it is better to say so up front than to certify a building on an inspection that could not see the defects.
What we find, again and again
Twenty five years in this trade produces a fairly predictable list. If your building has any of these, it is not compartmented, whatever the O&M manual says:
- Compartment walls terminating at the ceiling grid rather than running to the underside of the slab, leaving a continuous void above every room on the floor.
- Service penetrations sealed with the wrong product: general-purpose mastic instead of a tested fire-rated sealant, or a sealant used on a plastic pipe that needs a collar or wrap.
- Cavity barriers missing at the floor-to-facade junction, particularly on curtain walling and rainscreen systems, where the perimeter gap is the fastest route between storeys.
- Oversized apertures where a 50mm cable bundle passes through a 300mm hole with a bag of mineral wool pushed in behind it.
- Back-to-back socket boxes in compartment walls with no intumescent putty pads.
- Riser walls sealed at every floor except the top one, because the last one was awkward to reach.
- Systems installed correctly but with no record of it, which for certification purposes is very nearly as bad as not installing them.
Firestopping installation
We install tested systems, to the manufacturer’s detail, with the evidence recorded as we go:
- Fire-rated sealants, mastics and acoustic-rated equivalents
- Coated batt systems for mixed service penetrations
- Fire-rated mortar and compound for large apertures and floor voids
- Pipe collars, wraps and sleeves for combustible services
- Linear gap seals to head-of-wall, wall-to-wall and movement joints
- Cavity barriers, including curtain wall perimeter and rainscreen applications
- Intumescent putty pads, ducting protection and damper installation
- Fire-rated boarding and encasement
Products are used within the scope of their test evidence. If a manufacturer has not tested a system for your substrate, aperture size and service mix, we will say so and propose one that has, rather than applying an assessment that will not survive scrutiny.
The evidence pack, and why it decides the job
Since the Building Safety Act 2022 and the amendments made to the Fire Safety Order, the question is no longer only whether the work was done. It is whether you can prove it was done, by whom, using what, on what date.
Every penetration we seal gets a unique reference, a location, the substrate, the aperture size, the service passing through, the system and product used, the installer, the date and a photograph before and after. That builds into a handover pack that satisfies Regulation 38 information requirements and drops straight into the golden thread for a higher-risk building.
This is the part most contractors skip, and it is the part that gets a building held up at handover. It is also far harder to reconstruct six months later than to capture at the time.
Sectors we work in across London
Occupied hospitals and healthcare premises. Schools and universities working within term breaks. Residential blocks and social housing, including remediation programmes. Commercial offices and fit-outs. Listed and heritage buildings, where the compartmentation solution has to be reversible and sympathetic.
We have delivered passive fire protection on projects including the ABBA Arena, the British Library extension, the Royal Albert Hall and Canterbury Cathedral, for main contractors including Walter Lilly, Structure Tone, Severfield and McLaughlin & Harvey. You can see more of our work in our case studies.
Why ATOL
Third-party certified. BM TRADA Q-Mark and NAPFIS. Independently audited work, not self-declared compliance.
We survey before we price. You get a defect schedule you can act on, not a lump sum with no breakdown.
Evidence as standard. Photographic record per penetration, issued as a signed log book, not as an afterthought.
We work occupied buildings. Out of hours, phased by floor, with the disruption planned rather than discovered.
We will tell you when you do not need us. If a survey shows the compartmentation is sound and the problem is elsewhere, that is what the report will say.
Compartmentation is one part of the picture. We also apply intumescent coatings to structural steel and provide off-site shop-applied coating for steelwork fabricators.
Frequently asked questions
How much does a fire compartmentation survey cost in London?
It depends on floor area, how many compartment lines there are and whether opening-up is required. Send us a floor plan and the number of storeys and we will give you a fixed price rather than a day rate.
How long does a survey take?
A single office floor is usually a day. A residential block of forty flats with communal risers is typically three to five days on site, plus reporting.
Do I legally need a compartmentation survey?
The Regulatory Reform (Fire Safety) Order 2005, as amended by the Fire Safety Act 2021, requires the responsible person to assess fire risk including the structure and external walls. For most buildings a competent fire risk assessment will identify whether a compartmentation survey is needed. For higher-risk buildings the golden thread requirements make documented evidence effectively unavoidable.
What is the difference between fire stopping and compartmentation?
Compartmentation is the overall strategy of dividing a building into fire-resisting cells. Firestopping is the work of sealing the holes made through those cells by pipes, cables, ducts and structural junctions. Firestopping without a compartmentation strategy is sealing holes at random.
Can you work in an occupied building?
Yes. Most of our remedial work is in live buildings, phased around occupancy, with out-of-hours working where access demands it.
Do you provide certification?
Yes. Work is carried out under our third-party certification and issued with a per-item record and a signed fire protection log book.
Talk to us about your building
Send a floor plan, a fire strategy or a defect list and we will come back with a survey price or a priced remedial package.
Call 0330 094 9099 or email hello@atolconstruction.co.uk. You can also use our contact form.