Domestic Roofing

Getting multiple quotes is sensible. But price alone doesn’t tell you whether the work will be done correctly, last as long as it should, or protect your home insurance and property value. Here are four specific questions to ask any roofer before accepting a cheaper quote — each one relates to a requirement that is frequently skipped by contractors cutting corners on cost.

Do you nail every tile in a single lap system?

On a single lap tiled roof – the most common type on modern UK housing – every tile should be mechanically fixed with a nail or clip. BS 5534:2016, the British Standard governing slating and tiling, requires that all tiles in a single lap system are fixed individually. Many cheaper contractors only nail every other tile or fix tiles at the perimeters only, leaving the majority of the roof relying on their own weight and interlocking profile alone. This is non-compliant and significantly increases the risk of tiles lifting or displacing in high winds.

Do you fit eave clips and double fix all border tiles?

BS 5534:2016 requires that tiles at the eaves, verges, ridges and all other exposed perimeter positions are double fixed – meaning both nailed and clipped. Eave clips secure the bottom edge of the first course of tiles, which is the most vulnerable part of the roof in wind uplift. Skipping eave clips and border fixings is a common shortcut that reduces material and labour costs but leaves the most exposed areas of your roof inadequately secured.

What gauge of batten nails do they use?

This is a detail almost nobody thinks to ask but it matters considerably. BS 5534:2016 specifies that the minimum diameter for batten nails is 3.35mm. The more commonly available and cheaper 2.65mm nails are not approved under this standard and do not provide sufficient withdrawal resistance to hold battens securely to the rafter over the long term. Many contractors use 2.65mm nails simply because they are cheaper and more readily available. If your roofer cannot tell you the gauge of nail they use, or uses 2.65mm as standard, their installation is non-compliant regardless of how good the rest of the work looks.

Do you fit the vapour permeable underlay membrane with a rafter drape?

The underlay membrane laid beneath the tiles should not be pulled tight between rafters – it should be allowed to sag approximately 15mm between each rafter. This is called a rafter drape and it exists for a specific reason: any water that penetrates the tile covering needs somewhere to run to reach the gutters. A membrane pulled tight for convenience and speed creates a flat surface where water pools against the battens rather than draining away, accelerating batten rot and eventually causing structural deterioration beneath the tiles. The drape is a straightforward requirement that adds no material cost – only time and care. Contractors who skip it are prioritising speed over the long-term performance of your roof.

If a roofer cannot answer these four questions confidently, or tells you these requirements don’t apply or aren’t necessary, treat that as a significant warning sign. A lower quote that results in non-compliant work leaves you with a roof that may fail prematurely, void your manufacturer warranty, and create problems when you come to sell your property.

ACSAP installs all tiled and slated roofs in full compliance with BS 5534:2016 as standard. We are happy to walk through our specification with any customer before work begins.