Type 1 vs Type 2 vs Type 3 vs Type 4 FRA — which do you need?

The four-type model

The Type 1–4 classification comes from the Local Government Association / NFCC guidance on fire risk assessments in purpose-built blocks of flats. It's the most widely understood framework for scoping an assessment of a multi-occupied residential building.

Type 1 — Common parts only, non-destructive

The default starting point. The assessor inspects all common parts — escape routes, plant rooms, ancillary accommodation, the structure of the building as visible from those areas. No internal flat inspection beyond the front door. No opening up of construction. Appropriate for the majority of standard purpose-built blocks where the original construction is well documented and there's no reason to suspect concealed defects.

Type 2 — Common parts only, destructive

A Type 1 plus targeted destructive opening up — typically sample inspections of compartment walls and floors, riser cupboards, service penetrations. Required where there's reason to suspect compartmentation has been compromised but no need to look inside individual flats.

Type 3 — Common parts plus flats, non-destructive

Extends the Type 1 inspection into a sample of flat interiors — typically 10–20% of flats — looking at means of escape, flat entrance doors from the inside, and any visible compartmentation between flats. Used where the original flat construction is unclear or where there's been a history of unauthorised alterations.

Type 4 — Common parts plus flats, destructive

The most thorough — and most disruptive. Includes destructive opening up in flat interiors as well as common parts. Reserved for buildings where serious concerns have been identified at Type 1 or 2, or where regulatory pressure (e.g. post-Grenfell remediation) demands a full structural verification.

How to pick the right type

Start with Type 1. Move up only where the building's age, history, alterations or post-Grenfell scrutiny justifies it. Type 4 across a whole block runs to tens of thousands of pounds and is rarely proportionate without a specific trigger. We'll always quote the lowest type that genuinely satisfies the duty.