Type 1, 2, 3 and 4 fire risk assessments from £99

The four-type classification comes from the LGA guidance on fire safety in purpose-built blocks of flats and is now standard language across the sector. It exists because two questions have to be answered separately: how far into the building does the assessor look, and how much of the fabric do they open up. A block where the construction is well documented, the alterations are known and there is no history of compartmentation problems does not need someone lifting ceilings. A 1960s block that has been through three refurbishments with no records almost certainly does.

The standard assessment, and the right answer for the large majority of blocks. The assessor inspects the common parts — entrance, corridors, stairs, lobbies, plant and riser cupboards, refuse areas, roof access where reachable — and forms a view on compartmentation from what can be seen without opening anything up. Flat entrance doors are inspected from the common side. The assessment considers escape routes, detection and alarm, emergency lighting, signage, firefighting provision, ignition sources and management arrangements, and produces a prioritised action plan. A Type 1 is not a lesser assessment; it is the appropriate assessment where the fabric is not in doubt.

A Type 2 goes further by opening up parts of the structure in the common areas — typically ceiling voids, riser cupboards and service penetrations — to verify that compartmentation is genuinely as it appears. It is justified where there is a specific reason to doubt the fabric: unexplained smoke spread in a previous incident, evidence of unrecorded alterations, or a construction type known to be problematic. It is disruptive and requires making good afterwards, so it should follow a reason, not a preference. In practice a Type 2 is often scoped as targeted openings at specific locations identified during a Type 1, rather than as a whole-building exercise.

A Type 3 extends the assessment into a sample of the flats themselves, non-destructively. The assessor looks at the flat entrance door from both sides, the internal escape arrangements, smoke detection within the dwelling, and anything obvious that undermines compartmentation — an extractor cut through a party wall, a removed door, a boarded-over kitchen ceiling. This matters because a stay-put strategy depends on each flat containing a fire for long enough, and the common parts alone cannot tell you whether that is true. Type 3 is commonly required by landlords with a duty toward tenanted flats, and is increasingly requested where a stay-put strategy is being reviewed.

The most thorough and the least common. A Type 4 combines destructive inspection with entry into a sample of flats, and is normally commissioned where a building has known or suspected serious defects, is subject to a remediation programme, or where a safety case for a higher-risk building requires the fabric to be evidenced rather than assumed. It needs planning: resident consultation, access agreements, a contractor to open up and make good, and often a programme rather than a single visit.

In most cases the honest answer is Type 1, reviewed annually, with a Type 3 introduced where flats form part of the duty or a stay-put strategy is being tested. The trigger for going further is evidence, not anxiety.

Type 3 and Type 4 assessments look at a sample of flats, not all of them. A reasonable sample reflects the different flat layouts, floors and any known alteration patterns in the building, and the report records which flats were inspected and why. Where a sample reveals a systemic problem — several flat entrance doors replaced without fire-rated equivalents, for instance — the correct response is usually to widen the sample rather than to extrapolate. Access is the limiting factor: residents must agree, and a report that quietly notes low access has less value than one that says plainly how many flats were seen.

Most purpose-built blocks operate a stay-put strategy, which relies on each flat being a fire-resisting compartment. If flat entrance doors, party walls or floors have been compromised, stay-put may no longer be supportable — and that conclusion cannot be reached from the corridor alone. This is why a block whose evacuation strategy is under question usually needs at least a Type 3. Changing a strategy to simultaneous evacuation has significant cost and resident implications, so the evidence base for that decision matters.

Type 1 assessments follow standard pricing — from £149 for a two-storey communal block up to £1,899 for large high-rise buildings, with the figure driven by storeys, units and complexity. Type 3 is priced on the same basis plus the flat sample, so the number of dwellings inspected is the main variable. Type 2 and Type 4 involve opening up and making good, so they are scoped individually with the contractor element quoted separately and transparently. We will always tell you if you are being asked to buy a more intrusive type than the building justifies.