Building Control Inspections — What They Check and When They Visit

**Two routes to Building Control**: For most residential projects, there are two options:

1. **Local Authority Building Control (LABC)**: the building control team within the local council. Application is made by submitting a Full Plans application (complete drawings and specification reviewed before works start) or a Building Notice (simpler notification without pre-approval — inspector reviews as works progress). The local authority typically has a fixed fee schedule.

2. **Approved Inspector (AI)**: a private sector company authorised to carry out Building Control functions. The homeowner or contractor appoints the AI, who provides the same service as the local authority team. AI fees are negotiated and may be lower than local authority fees for larger projects.

**Important**: once you choose an Approved Inspector, you must notify the local authority that you are using a private AI. If the AI later withdraws (which can happen if not paid), the local authority takes over — but may not accept all prior inspections.

**The key message**: whichever route is used, the stage inspections are broadly the same, and the completion certificate (or final certificate from an AI) is the essential document confirming compliance.

• **The foundation/excavation inspection**:
• The inspector visits before concrete is poured to confirm:
• •The excavations are at the correct depth and in adequate ground
• •The width and type of foundation is appropriate for the ground conditions and structural loads
• •No services or drainage conflicts with the foundation position

Typically: inspector must be called to inspect before concrete is poured. If the inspector cannot visit in time and concrete is poured first, there may be a dispute about compliance.

**The oversite (damp proof membrane) inspection**: The inspector confirms that the oversite concrete slab and damp proof membrane are installed correctly before the floor screed or covering is applied. This protects against damp rising through the ground floor.

• **The structural frame inspection**:
• For loft conversions and extensions involving new structural work, the inspector checks:
• •Steel beam sizes match the structural engineer's specification
• •Padstones and bearing lengths are correct
• •Connections are as specified
• •No temporary works have been removed prematurely

• **The drainage inspection**:
• Before drainage is covered, the inspector checks:
• •Pipe falls are correct (typically 1:40 for waste, 1:80 for soil)
• •Inspection access is provided at all bends and junctions
• •Materials are appropriate
• •Connection to sewer or soakaway is compliant

**The insulation inspection**: The inspector confirms that insulation is installed correctly — correct thickness, correct material, correct position in the build-up, and that thermal bridges are addressed. For loft conversions, this is typically the rafter or between-joist insulation before it is boarded.

• **The final/completion inspection**:
• The most comprehensive inspection, checking:
• •All fire doors are installed on the staircase and meet FD30S specification
• •Smoke alarms are installed at each level and are mains-wired and interlinked
• •The staircase meets Part K requirements (rise, going, width, handrail)
• •Glazing is safety glazing in critical locations
• •Electrical installation has been certified (Part P)
• •All structural, drainage, and insulation work has been completed as specified
• •The structure is complete and ready for habitation

• **If the inspector is not satisfied**:
• The inspector will note the non-compliance and either:
• •Require the works to be corrected before the next inspection
• •Issue a formal notice of non-compliance
• •In serious cases, issue an enforcement notice requiring the works to be opened up or removed

• **Common issues found at inspections**:
• •Foundation depth insufficient — inspector requires excavation to proceed deeper before concrete
• •Insulation specification does not meet Part L — additional insulation required
• •Fire doors not FD30S — doors require replacement
• •Structural beam size different from specification — engineer's written confirmation required that the substitution is acceptable
• •Drains not inspected before covering — may require opening up

• **How to prepare for stage inspections**:
• •Ensure the Building Control body has the correct contact number for the site and contractor
• •Call for inspections as soon as each stage is ready — do not pour concrete, cover drains, or cover insulation without the inspection being completed or being waived in writing
• •Ensure the structural engineer's drawings and specification are on site for the inspector to reference
• •Have fire door specifications and certificates available for the final inspection
• •Part P electrical certificate should be obtained and available at the final inspection

• **After the final inspection — the completion certificate**:
• Once satisfied, the Building Control body issues a completion certificate (or, for an Approved Inspector, a final certificate). This document confirms the works comply with Building Regulations and is essential for:
• •Any future sale of the property
• •Mortgage lender confirmation (where the lender's conditions require it)
• •Insurance purposes
• •Your own peace of mind