Natural slates are imported to Ireland from all over the world; Spain, Brazil, Wales, China, Canada, America and France. Quality can vary between the slates and their sources and there are many various grades available in Natural Slates. At Roof Survey we believe (in most cases), a natural slate roof is only as good as its application – a good, experienced roofer can make a bad slate look good and an amateur roofer can make a good slate look bad on a finished roof. Typical natural slate problems can include:
Rusting. Many slates contain various inclusions known as pyrite, some of this mineral can react with the atmosphere causing various degrees of leaching.
Non flatness. Common problem in Ireland, some slates can be misrepresentated as being flat and reasonably uniform. In reality a significant amount of workmanship can be needed to apply the slates.
Bad grading and sorting. Another legacy from the boom years, little time was given to grading and sorting the roof, leaving unsightly gaps and kicks all over a roof.
Improper fixings. Roofsurvey always recommend the use of good quality and correctly sized copper nails and stainless steel hooks.
All natural slates used in Ireland should conform to EN 12326-1:2004 and be applied in accordance with I.C.P.2: 2002 (based on BS5534) with reference made to BS8000:2011.