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Fire compartmentation

Fire compartmentation divides a building into boxes of fire-resisting walls and floors, so a fire stays in the room, flat or floor where it starts long enough for people to get out and firefighters to get in. In blocks of flats it is what makes a stay put policy safe.

Remediation is the work to put it back: rebuilding wall heads above ceilings, sealing floors in risers, boarding, fire stopping and fixing doors. University of the West of England paid £92,664 in 2024 for fire remedial works to 18 flats, about £5,100 a flat on average.

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Sheet
PF-03
Subject
Compartmentation remediation
Scope
England, Scotland, Wales
Prices read
November 2026

PF-03.1

Signs compartmentation needs work

  • Walls stop at the suspended ceiling instead of running up to the slab above.
  • Risers and service shafts are open between floors.
  • Loft spaces run across flats or units with no fire-resisting division.
  • Doors to stairs, lobbies or flats do not close, or have been replaced with ordinary doors.
  • A survey has listed more defects than a few seals can fix.
  • The building has changed use, such as offices converted to flats.

PF-03.2

What compartmentation remediation costs

ItemPublished figure
Fire remedial works, 18 flats
University of the West of England, July 2024, contract value as published		£92,664
Fire stopping, compartmentation and doors, one block
East Suffolk Council, May 2023, contract value as published		£332,329
Surveys and remediation framework, three years
South London and Maudsley NHS Foundation Trust, February 2026, contract value as published		£4,400,000
Compartmentation surveys and remediation framework, lot 1
Believe Housing, January 2026, contract value as published		£3,770,000
Where these figures come from

Public contract values are the published figure on each award notice, excluding VAT where the notice says so. They show the scale of real jobs, not a rate for yours. Notices: University of the West of England, East Suffolk Council, South London and Maudsley NHS Foundation Trust, Believe Housing. Framework values are the most that can be spent across many buildings over the term. The passive fire protection cost guide explains what drives the price.

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PF-03.3

What sound remediation covers

The parts of the job that decide whether it holds up in a fire.

  1. Priced against a survey

    Every line tied to a defect reference from the survey, so you know exactly what is being fixed and what is not.

  2. Tested systems, named

    Each seal, door or coating named by product and the test evidence it relies on, and confirmation it suits the wall or floor type and the services passing through.

  3. Full-height walls

    Where walls stop at the ceiling, how they will be taken up to the slab or roof, and what boards or systems are used.

  4. Third-party certification

    Whether the firm holds a third-party installer scheme for this work, and the certificate number so you can check it on the scheme register yourself.

  5. Records you can keep

    Photographs of every item before and after, a unique reference or label for each, and a schedule you can hand to the next fire risk assessor or put in the golden thread.

  6. What is left out

    Making good, decoration, asbestos, out-of-hours working and anything found once ceilings or boxing come down, priced as separate lines.

Have a survey that needs pricing? Tell us about the building and get the remedial works quoted.

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PF-03.4

How remediation usually runs

  1. Brief

    Share the fire risk assessment, the fire strategy if there is one, floor plans and any earlier survey. Say what prompted the work and any deadline.

  2. Check the survey

    The contractor walks the building against the defect schedule and confirms access, quantities and any extra items.

  3. Quote

    A priced schedule against the survey, naming the tested product for each item and listing exclusions.

  4. Works

    Items are fixed in a planned order, with access agreed with residents or occupiers and hot works, asbestos and permits handled first.

  5. Handover

    Photographs, labels and certificates for every item, handed over for your records and the next fire risk assessment.

PF-03.5

Questions people ask

What is fire compartmentation?

Dividing a building into separate fire-resisting compartments with walls, floors and doors that resist fire for a set time, usually 30, 60 or 120 minutes. Each compartment holds a fire long enough for people elsewhere to stay safe or escape.

What is the difference between compartmentation and fire stopping?

Compartmentation is the whole fire-resisting structure. Fire stopping is one part of it: the seals where services and joints pass through. Remediation often needs both, plus boarding, cavity barriers and door work.

How long should compartment walls resist fire?

It depends on the building's use and height. Approved Document B sets the periods for new buildings in England, commonly 60 minutes and up to 120 minutes in taller buildings. Your fire strategy or fire risk assessment should say what yours need.

Can people stay in the building during the work?

Usually, yes. Contractors work floor by floor or flat by flat, keep escape routes clear, and agree hours with occupiers. Some work inside flats needs residents to give access.

Do we need building regulations approval?

Some remedial work counts as building work, especially in higher-risk buildings, where work now goes through the Building Safety Regulator. Ask your contractor or building control before starting larger jobs.

What evidence should we get at the end?

Photos and a label or reference for every item, the products used, any certificates under a third-party scheme and an updated plan. Keep them with the fire risk assessment and, for higher-risk buildings, in the golden thread.

See also

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