BS 5534 Roof Survey

The first stage of a BS 5534 roof survey is to consider whether the roof covering appears suitable for the building, pitch, exposure and roof form.

We may inspect:

• Natural slate, fibre cement slate, clay tile and concrete tile coverings.
• Suitability of the covering for the roof pitch and exposure.
• Evidence of slipping, distortion, delamination, cracking or surface deterioration.
• Tile or slate coursing, alignment, gauge and visible laps.
• Compatibility of covering, underlay, battens and fixing method.

Where defects are visible, we explain whether the issue appears isolated, workmanship-related, age-related or potentially systemic.

Incorrect laps are a common cause of water penetration, wind-driven rain entry and premature failure. A BS 5534 roof survey may consider whether slates or tiles appear to have been laid at a suitable gauge and whether the roof has adequate resistance to rain and snow under normal exposure conditions.

Typical issues include:

• Insufficient headlap.
• Incorrect sidelap.
• Over-gauged battens.
• Roof covering used below suitable pitch.
• Vulnerable detailing around valleys, abutments and roof penetrations.

These defects are particularly important where a roof has been recently re-covered, where leaks are recurring, or where the contractor’s workmanship is being challenged.

Roofing battens are not simply packing pieces. They support the roof covering, receive fixings and form part of the overall roof system. Defective battens can lead to loose coverings, fixing failure, distortion and reduced roof performance.

Our pitched roof surveys may consider:

• Batten size and visible condition.
• Evidence of decay, splitting, distortion or inadequate support.
• Whether battens appear suitable for the covering and rafter spacing.
• Whether visible batten gauge appears consistent.
• Whether counterbattens or ventilation routes are required.

Where battens are hidden, we may recommend targeted opening-up or further investigation if there is sufficient evidence of concealed risk.

Underlay defects are a frequent finding in a BS 5534 roof survey. Underlays can be damaged by poor installation, excessive exposure before the roof covering is installed, incorrect draping, poor laps, UV degradation or incompatible ventilation strategy.

We may assess:

• Whether the underlay is torn, sagging, brittle or poorly lapped.
• Whether water is tracking beneath the covering.
• Whether underlay has been dressed correctly into gutters and valleys.
• Whether penetrations, abutments and laps are vulnerable.
• Whether underlay selection creates condensation or ventilation risks.

Underlay condition is especially important where a roof is leaking despite the main roof covering appearing visually acceptable.

Modern pitched roofing relies on appropriate mechanical fixing. Mortar alone should not be relied upon to secure vulnerable components, and exposed roof areas often require particular attention.

Our survey may consider:

• Missing, inadequate or corroded fixings.
• Evidence of nail fatigue or fixing pull-out.
• Tile clips, slate hooks, nails and screws where visible.
• Insecure eaves, verges, ridges and hips.
• Storm damage risk and wind uplift vulnerability.

Where fixing adequacy cannot be confirmed visually, we explain the limitation and identify whether opening-up, manufacturer data or contractor installation records should be requested.

Ridges, hips and verges are exposed parts of the roof and often show early signs of poor fixing or poor workmanship. A BS 5534 roof survey may also consider dry-fixed ridge, hip and verge systems with reference to manufacturer guidance and relevant good practice.

Common defects include:

• Loose ridge or hip tiles.
• Displaced dry verge units.
• Insufficient mechanical fixing.
• Failed mortar bedding or poor pointing.
• Weathering gaps at ridge, verge or hip junctions.

These issues are often visible from a drone roof survey, but high-level inspection, scaffold access or local opening-up may be required where the cause is disputed.

Many pitched roof failures occur at junctions rather than across the main field of tiles or slates. Valleys, abutments, chimneys, dormers, rooflights and changes in roof pitch require careful detailing.

We may inspect:

• Valley width, lining condition and water flow.
• Tile cutting and support at valleys.
• Flashings and soakers at abutments.
• Weathering around chimneys and rooflights.
• Evidence of water staining, debris blockage or hidden water paths.

Where leadwork is a significant part of the defect, we may recommend a linked BS 6915 leadwork survey.

Not every roof leak is a leak. Condensation, trapped moisture and air leakage can create staining, mould, timber decay and insulation damage. A BS 5534 roof survey may identify where a linked moisture assessment is required.

We may consider:

• Roof void ventilation.
• Blocked eaves ventilation.
• Inappropriate insulation placement.
• Air leakage into cold roof voids.
• Condensation risk around underlays and roof junctions.

Where moisture risk is central, the investigation may also need to consider BS 5250 condensation and moisture risk.