All slates have to have a good standard of skill as well as experience on the function for the slater. One of the most important aspects of this is taking care to deal with the dimensional variations from slate to slate. To help make this particular smoother and hence to ensure the slating cost is reasonable, restrictions are set on the variations in length, width, edge straightness, rectangularity, flatness and thickness, and there are tests for the every one of these. Most of these limits do not apply towards random sized slates simply because their dimensions are undefined. Visit We Buy Slates for reclaimed slates in Sheffield, South Yorkshire.
Except for all those aspects to surface texture which impact flatness, generally there are no requirements for appearance in the standard. All of these, especially colour and colour changes needs to be agreed between supplier and specifier or purchaser. Colour is the especially difficult property to standardise because it changes over time