Raising your roofing standards: BS5534 for pitched roofs
Both new and replaced pitched roofs can look fantastic when viewed from the ground. But how can you as the building owner be confident that whilst the work looks good, the roof will perform and keep water out of the building in the long term? There are several key elements, which must be correct in terms of the installation, and these are enshrined in British Standard 5534:2014 (plus amendments). You need to be certain that your roofing contractor is always working to this standard to ensure that their performance meets your expectations, but also that the roof complies with current Building Regulations and compliance with BS8000 is part of achieving this standard and meeting the regulations.
At its basic level, BS5534 covers items like the fixings, the battens and head lap and side lap (the overlap of the slates or tiles). How many people know, for example, that there are only three acceptable forms of nails for slates? Those being copper, alloy or silicon bronze. Their length, width and head size are tightly prescribed in the standard. If you see galvanised clout nails being used for your slate fixings, these are not appropriate and will lead to early failure.
Similarly, the battens used must be stamped with BS5534 from a reputable supplier. To achieve this standard, they must have been checked for straightness, knots and other faults prior to arriving on site. If battens do not contain this stamp, they are not roofing battens at all – they are simply pieces of timber. Since operatives use battens as steps when walking on the roof, battens to the correct standard are imperative as inferior battens may break under a person’s weight and could lead to a fall. Batten nails also have very tightly prescribed sizing, as does the overlap of the slates themselves. The standard also contains a map of the British Isles which splits the four countries into ‘zones’ of wind loading and rainfall amounts. If your property is by the sea for example, it will be subject to much higher winds than a low-lying inland town and, accordingly, the headlap must be greater to take account of wind and water.
The correct membrane must also be used as the secondary defence for water ingress. The way the membrane is installed is outlined in the standard, likewise the type of material it is made from. This is important since a roof works as a ‘system’ to keep water out, but also to ensure that condensation doesn’t form inside the building. If you have bats in your area, certain fibrous membranes must not be used as they can be harmful and, if they are used, heavy fines can be imposed by Natural England.
A competent roofing contractor will work to BS5534 on every job they do. At CRS, we have many years’ experience in working on pitched roofs, from slate to tile and new roofs to replacements. These include heritage buildings, Ministry of Defence accommodation, stately homes and large private dwellings. As we are a member of the NFRC Competent Person Scheme for roofing, we are authorised to self-certify our work to Building Regulations, saving the cost of Building Control inspection(s). As part of that, we can also offer insurance backed guarantees on our refurbishment work.
Let us survey your roof and we will apply these standards, pointing out areas of weakness, potential failure or current failure, along with the reasons why. Our experienced Surveyors, Senior Managers and Directors have many years’ experience and are fully conversant with BS5534, as well as being Members of the Institute of Roofing (the professional body for roofing managers).