The quality of Welsh slate roofing is such that even after 100 years of use at least 50% is typically re-used. There are buildings around the world which have Welsh slate roofing tiles which are several hundred years old. There is no other roofing material which has demonstrated this extraordinary durability; making Welsh slate a very cost effective roofing material. It is unaffected by normal extremes of temperature and is highly resistant to acids, alkalis and other chemicals. Bayford Roofing has extensive experience in installing and repairing Welsh Slate Roofs.