Compartmentation failures are the leading cause of fire spread in multi-occupancy buildings. We explain why surveys are now essential and what they involve.. The Hidden Threat Inside Walls Fire compartmentation — the system of fire resistant walls, floors, and barriers that contain fire within defined zones — is arguably the single most critical passive fire protection measure in any multi occupancy building. Yet it is also the most commonly compromised. Across the UK, decades of poorly managed building works, service installations, and maintenance interventions have left thousands of buildings with breached compartmentation. Holes drilled through fire walls for cables, pipes, and ducts — then left unsealed — create hidden pathways for fire and smoke to spread unchecked through a structure. Why 2026 Is the Tipping Point Several regulatory and enforcement developments have converged to make compartmentation surveys not just advisable but effectively mandatory: Building Safety Act 2022 — Higher risk buildings must maintain a 'golden thread' of building safety information, including compartmentation data Fire Safety (England) Regulations 2022 — Responsible Persons must assess and manage fire doors, external walls, and by extension, internal compartmentation PAS 9980 — The standard for assessing external wall fire risk explicitly considers internal fire spread via breached compartmentation Increased enforcement — Fire and Rescue Services are conducting more intrusive inspections and issuing enforcement notices for compartmentation failures What Does a Compartmentation Survey Involve? A comprehensive compartmentation survey is a forensic examination of a building's passive fire protection systems: Phase 1: Desktop Review Original architectural drawings and fire strategy Building control records and completion certificates Previous fire risk assessments and remediation records Service installation records and maintenance logs Phase 2: Intrusive Inspection Opening up ceiling voids, risers, and service ducts Inspecting fire barriers at compartment boundaries Checking fire stopping around all penetrations Assessing fire door sets and their frames Examining junctions between different construction types Phase 3: Reporting and Remediation Detailed photographic record of all deficiencies Risk rated findings with recommended remediation Prioritised action plan with indicative costs Specifications for remedial fire stopping works Common Failures Found During Surveys Our experience of surveying hundreds of UK buildings reveals consistent patterns of failure: Unsealed service penetrations — The most common finding. Electricians, plumbers, and data installers routinely breach fire walls without reinstating fire stopping Missing fire barriers in ceiling voids — Suspended ceilings often conceal the absence of fire barriers that should prevent horizontal fire spread Inadequate fire stopping materials — Combustible expanding foam used instead of tested fire stopping products Damaged or missing cavity barriers — Particularly in timber frame and rainscreen cladding systems Fire door deficiencies — Gaps, missing intumescent strips, non fire rated ironmongery The Cost of Ignoring Compartmentation The financial argument for compartmentation surveys is compelling: Scenario Typical Cost Compartmentation survey (100 unit block) £15,000–£30,000 Remedial fire stopping works £20,000–£100,000 Insurance premium increase (poor compartmentation) 200–500% Fire damage claim (uncontained fire) £2M–£20M+ Regulatory prosecution (negligence) Unlimited fines + imprisonment Selecting a Competent Surveyor Not all fire stopping surveys are equal. Key criteria for selecting a surveyor: Independence — The surveyor should not also be the fire stopping contractor (conflict of interest) Qualifications — IFE membership, BAFE accreditation, or equivalent Experience — Demonstrated track record in similar building types Insurance — Adequate professional indemnity cover Methodology — Clear, systematic approach with defined scope For independent compartmentation surveys across the UK, contact Magnus Opifex.