Reminder: Be extremely vigilant when choosing your slate

An increase in incorrectly marked and inferior slate coming into the UK market poses a worrying threat to merchants and contractors, warns SIG Roofing Supplies – the leading supply chain experts of roofing materials in the UK and the largest distributor of natural slate in Europe.

Following the recent collapse of the slate market in France and the desperate bid by some Spanish quarries to make up their volumes elsewhere, rust-risk (effectively T2) slates are being badged and sold as T1 slate. UK roofers are buying these ‘competitive’ slates, often a little cheaper than good, reliable T1 slate, completely unaware of the risks they are taking. While some quarries may even have “T1” certification for some of their product, they will have such a history of rust that knowledgeable importers will avoid them – or sell it as T2. The temptation for some distributors is to hope for the best and sell them “as seen” and their after-sales service may be no better than their slates.

SIGA’s Slate Category Manager, Joe Bordas explains: “Concern is escalating regarding this situation as UK roofers are being duped into thinking they have a genuine bargain. Not only are roofers being deliberately misled, these slates are often ones our experienced buyers have already investigated, considered, and turned down due to excessive risk; either in the rock use or commercially.”

Bordas advises: “Slate should always be selected from a reputable supplier and a copy of the BS EN12326 Declaration of Performance obtained. This will enable the key physical properties of the slate to be compared in order to ensure it’s up to the job in hand. The most critical areas are frost resistance, visible rusting, and structural integrity, and these are all covered by the Declaration of Performance.”

Unfortunately, roofing contractors take traceability and enforceable warranties for granted, and many only ever ask for certificates or CE Declarations of Performance once the complaints begin. It’s only when confronted with the serious problems of hidden carbon content and the high risk of rust, damaging micro pyrites and excessive water absorption, that roofing contractors begin to realise that the high wastage, for which cheap and inferior slate is renowned, is the least of their problems.

From this July, it will be even more critical to ask for BS EN12326 certification and CE crate labeling: Local Authority Building Control will be looking for this on all products to which the Construction Products Regulation applies, including natural slate.

Bordas also advises: “The growing trend for extended warranties – some being 100 years – compounds the problem further. Roofers think they are being offered a safety net, but sadly most of the companies won’t be around anywhere near long enough to honour their promises. Most slates are 500 million years old to start with, but only highly experienced importers will know how the rock will fare once split and laid on a roof.”

SIG Roofing cautions that when choosing natural slate, it is now more important than ever before not to cut corners, and to insist on best value, not just the best price. In the same way householders expect to see examples of a roofer’s previous work, roofers and architects should view or visit sites roofed with the proposed slate, particularly given the initial cost of natural roofing. Longevity of supply is another forgotten requirement, as spares always seem to be necessary.

SIG Roofing currently sells over 13 million slates a year across the UK via its SIGA collection. Largely sourced direct from quarries located all over the world in major slate producing countries such as Spain, Wales, China and Canada, the SIGA range meets the key essential criteria of BS EN12326 test results and certification, CE labeling, consistency and security of supply, and consistency of quality.

Bordas concludes: “More than with any other roofing material, with natural slate – ‘you get what you pay for’. There is always cheap slate around, but there will always be a reason that it’s cheap, so roofers need to buy with their eyes wide open. In the long run, the client will thank you for it.”

---

This post was written by SIGA Slate Team