If you can't see it, you can't trust it. Compartmentation failures are the hidden killer in UK buildings — and surveys are revealing terrifying defects in buildings of all ages.. The Invisible Fire Safety System Compartmentation is the most critical fire safety system in any building — and the most frequently compromised. Unlike sprinklers or fire alarms, compartmentation is hidden within walls, floors, and ceilings. When it fails, there is no warning. What Is Compartmentation? Compartmentation divides a building into fire resistant compartments. Each compartment is designed to contain a fire for a specified period (typically 30 or 60 minutes), preventing spread to adjoining compartments. This is achieved through: Fire resistant walls — typically blockwork, concrete, or fire rated plasterboard Fire resistant floors — concrete slabs or fire rated timber constructions Fire stopping — sealing penetrations through fire resistant elements Cavity barriers — preventing fire spread through concealed spaces Fire doors — maintaining compartmentation at openings Why Compartmentation Fails Our surveys consistently identify the same categories of failure: 30% Missing fire stopping at service penetrations 25% Inadequate or missing cavity barriers 18% Fire stopping installed but incorrect product or poor workmanship 15% Breaches created by subsequent maintenance or modification works 12% Original construction defects never identified "In a recent survey of a 2015 built residential tower, we identified 847 individual compartmentation breaches across 120 flats. Every single riser cupboard had missing or defective fire stopping." Types of Compartmentation Survey Type 1: Non Invasive Visual Survey Inspection of visible elements: fire doors, service risers, ceiling voids (where accessible) Suitable for initial screening and prioritisation Limitations: cannot see behind walls or within concealed spaces Cost: £2,000 £5,000 for a typical residential block Type 2: Sampling Survey Targeted invasive inspection at key locations (typically 10 20% of the building) Opening up of sample walls, floors, and ceilings Endoscopic inspection of cavity spaces Cost: £8,000 £20,000 for a typical residential block Type 3: Comprehensive Invasive Survey Full inspection of all compartment walls, floors, and service penetrations Opening up at every floor in every riser Full cavity barrier verification in external walls and roof spaces Cost: £25,000 £60,000 for a typical residential block Type 4: Destructive Testing Laboratory testing of samples removed from the building Used when the performance of installed materials is in doubt Typically follows a Type 2 or 3 survey that identifies concerns Cost: Varies based on scope What We Find: Real World Examples Case Study 1: 2008 Residential Tower, Manchester Building : 14 storey, 92 flats Survey type : Type 3 (comprehensive invasive) Findings : 1,247 individual defects Critical defects : 312 (fire stopping completely missing at service penetrations) Remediation cost : £380,000 Time to complete : 8 months Case Study 2: 2016 Student Accommodation, Birmingham Building : 6 storey, 280 bed spaces Survey type : Type 2 (sampling) Findings : Systematic failure of cavity barriers in external wall Critical defects : Cavity barriers missing from 100% of sampled locations Remediation cost : £1.2 million (required extensive external wall works) Time to complete : 14 months Legal Obligations Fire Safety (England) Regulations 2022 The Responsible Person must: Ensure that compartmentation is maintained in good condition Include compartmentation in the scope of fire risk assessments Record the condition of compartmentation elements Take action to remediate any identified defects Building Safety Act 2022 For higher risk buildings, the Accountable Person must: Include compartmentation condition in the Safety Case Report Maintain records of compartmentation as part of the Golden Thread Report any compartmentation concerns to the BSR Magnus Opifex Compartmentation Services All four survey types delivered by qualified fire stopping inspectors Third party accredited (FIRAS, IFC, BRE) assessors Digital reporting with photographic evidence and CAD floor plans Remediation specification with budget grade cost estimates Remediation project management including procurement and installation oversight Completion certification with third party verification What's behind your walls could be putting lives at risk. Book a compartmentation survey.