AN INTRODUCTION TO SLATE
What is Slate? Slate is a stone formed from the very fine sentiment of primordial swamps.
It is this history that defines the very nature of Slate. Fine layers of silt laid down over millions of years compress and harden and to form a stone that can be hard, resistant to water penetration and unusually for a stone, has a very high tensile strength.
The high tensile strength of slate is due to the layered nature of the stone, this can best be seen by the application of Slate as roofing tiles. Slates can be split very thin to form a strong light weight roofing covering that has been used for thousands of years and indeed is still widely used to day, and can be considered as one of the best quality types of roofing tile available.
The most common colors for Slate are black gray and green. Welsh slates are considered to be among the finest quality slates available in the world. Available in tiles and cut to size slabs, welsh slate is highly suitable for both internal and external use. A wide variety of slates are now being imported from China, Brazil and other more exotic parts of the world. However one must take great care in ascertaining the suitability of the slates for the application to which it will be applied. Many of these types of Slate are unsuitable for external use as the colors will often fade or bleach in the sun.
The surface off the slate can be finished in two different ways is the "riven" or "honed. Honed slate also sometimes called polished, can be used as tiles on fireplace hearths and kitchen worktops.
The term "riven" means the finish that naturally occurs when the slate is split along its bed, the finish is rough and grainy and can sometimes (rarely!) reveal the fossilized remains of ancient creatures and plants.
This roughness makes for a slip resistant surface making this finish ideal for flooring and steps.
Slate roofing tiles are always supplied with a natural riven finish as this is the cheapest way of producing the tile. Welsh Slate has always been the slate of choice for roofing tiles it's durability and suitability for the job proven over hundreds of years. Today in many alternatives are valuable from China and Brazil but some of these slates may be prone to fading in the sunlight, so consultation with your supplier is absolutely essential.
Natural slates have subtle variations in color and shade that no artificial material can match, natural slates will age and weather gracefully in a way that no artificial alternative will do. If you are in the process of trying to choose between a natural slight or a cheaper alternative please read some of the articles on this website I hope they will persuade you of the virtues of buying the natural material.