Roofing Slate FAQ’s

What are Slate Products?

Slate is the fine grained stone formed from shale, sedimentary rocks and clay formed over millions of years. It is as popular today as it was in the era of the industrial revolution, when the first large scale mining started. Since then slate has been mined in every corner of the world, producing colours and textures that can appeal to the traditionalist and the modernist alike.

How are Slates fixed?
Generally, all slates are fixed using two copper nails although in the case of fibre cement slates the tail of the slate is also restrained using a copper disc rivet.

How long can I expect slates to last on my roof?
30 years minimum for fibre cement products, and between 30 – 100 years for natural slates.
A number of factors and types can affect a slates lifetime.

What factors should be taken into account when selecting tiles and slates for my roof?
The ability of a slate to perform saisfactorily will depend on the design details, roof pitch, laps, gaps as laid and geometry of the product in relation to the roof. Also the weight, design, orientation, location, geometry, and micro-climate affecting the roof is important.

I am a DIY roofer undertaking my own roofing project, do you have general guidance on tiling and slating?
Slate has many advantages: The outstanding insulation from heat and cold; Resistance to acid and pollutants; A fireproof building material; An impermeable barrier to water; A highly slip resistant material; Long life and durability; Resistance to chipping, cracking and abrasion; A long life and fireproof roofing material; High strength material; The warmth and elegance of a natural stone; Many different colors including greens, grays, reds, multicolor and so on.

We have around thirty years experience in the slate industry and are happy to give you technical information and advice.

• How many slate colours are available?
The most common shades available are Blue, Blue Grey, Grey, Green, Grey Green, Red and Purple.

• What is meant by Weathering, Semi Weathering, Fading, Non-Fading Slates?
A Non-Fading Slate is one which changes very little from when it is first quarried and any slight changes will be relatively uniform on the roof. Any slate which is not a Non-Fading slate is known as a Fading slate or Semi Weathering or Weathering Slate. The amount of colour change varies from product to product.

• What sizes of roof slate are available?
The traditional common sizes are 600x300mm, 500x300mm, 500x250mm, 400x250mm, 400x200mm

• How thick are roof slates?
Roofing slate vary in thickness, a nominal 5-7mm is typical, however for Scotland particularly in the Highlands a heavier 7-9mm is traditionally used.

• Do roof slates need grading?
Yes, slate should be sorted into at least three separate grades, (heavy, medium and thin). The thicker slates should be used on the lower roof (eaves), medium slates in the middle of the roof and thin slates on the higher roof (Ridge) section.

• What size of batten do I need to use?
Slate battens should be 50x25mm and should be used in accordance with British Standards BS5534 Part1 2003.

• What nails should I use for fixing the slates?
Copper or Aluminium nails should be used to British Standard BS1202 3.3mm diameter.

• What are slate and half slates and why do i need to buy them?
A slate and half slate is used on the verge on alternate courses to create the horizontal lap. A slate and half may also be required on areas of the roof where slates need to be cut, for example around roof lights, chimney stacks etc. The use of slate and half slates ensures the width of any slate on the roof is more than the minimum width allowed for British Standards BS5534 which is 150mm

• What is the best way of ensuring I get a quality slate?
Purchase slates from a reputable supplier that can supply full documentation for their products. Documentation should include independent test reports, Declaration of Performance Certificates and written guarantees on completion of the project.