CALL US: 01282 423 444
Local charges apply
11 Dec
British Standards are frequently ignored but none so more than BS 8000 Part 6 1990 Code of Practice for Slating and Tiling. This is initially done so to save on costs and time and usually ending with devastating consequences.
Sorting slates by thickness is just as important a part of the slating process as fixing them. Slates must be graded on the ground, before being lifted to the roof.
According to the British Standard, “Slates should be sorted into three of four groups of equal thickness”. Slates should be laid with equal thickness in any one course with the thicker end at the tail and thicker slates should be laid in the lower course with thinner slates in the upper course”
Sorting and grading the slates gives the roof a much stronger resistance to wind uplift and an improved aesthetic finish.
When slates are not sorted before being fixed on the roof, they kick-up and create dangerous gaps and risk being blown from the roof.
A lot of the time the blame of an awful looking and performing roof is directed back to the slate supplier. Slates are a natural product and unlike man-made products, they cannot be exactly the same in thickness due to the fact that they are split by hand. A tolerance of 20% in the variation of thickness is accepted and this can mean a significant variance when applied to the product.
It should be noted that anything other than premium grade quality of slates will need more sorting and grading before fixing on the roof. The roofer will be expected to cut down some of the slates with larger thickness tolerances for use on eaves and under eaves courses to keep waste to a minimum. This should always be considered when deciding which grade of slate to purchase.
So, if you have a roof that looks uneven, has slates that kick-up and look un-attractive then you need look no further than to question whether the slates were sorted and graded before being applied to the roof as required by the British Standard.