Slate for use on a driveway or path can come in three distinct forms: paving slabs, slate waste used as gravel and, more recently, rows of thin slate such as reclaimed roof tiles set on their edge in designer gardens.
Traditional Uses for Slate
Slate has traditionally been used as a driveway material or for paving in those parts of the country where there’s a good local supply. This is largely down to the weight of slate, in particular the thick slabs needed for paving. Thinner slates used for roofing don’t require so much weight for each job, so they have been worth transporting in the past.
Thin slate will crack very easily so paving slabs cut from slate will be considerably thicker than other stone. Add in slate’s very structure and you have increased weight per square metre over many other driveway materials. As transport has improved over the decades slate can now be transported more widely, to the point where cheap imports from China, India and other Asian and Far Eastern locations now threaten the UK’s more traditional slate supplying areas.
Slate used in paving slab form comes in a variety of colours, although they are all dark, of course. Welsh slate tends towards a blue or purple hue, while slate from the Lake District gives a greener colour. The lesser known Cornish slate can be rusty brown and gold, and there are others that are a more straightforward grey, including those from Dartmoor and Ireland.
Much of the imported slate from around the world offers more vivid colours, such as peacock blue and many different golds. Care needs to be taken with these as a lot of the decorative streaks in imported slate come from deposits of metals in the rock. These can cause weak spots, leading to cracks, or be covered up with the mud and grime of daily use. Check these slates carefully before deciding exactly where to lay them.
Reusing Slate Waste By-products
By-products of the slate industry include shale and other small particles, ranging in size from dust to fragments of broken slabs. This can be used for infill and sub-grades and also top dressing in place of Gravel. It can be more slippery than gravel, so care is required where it is used.
There is a real abundance of this material as there is much more produced than used right now. This may change as the UK government’s efforts to tax quarried materials (to make them less popular and discourage quarrying) could see greater use being made of these already quarried by-products.
Roof Slates for Paths
The new trend seen at garden shows over the last few years is to use rows of roofing slate (or at least similar widths of cut slate) set on their edge. This is more a decorative feature than a practical one but the method is gaining in popularity nonetheless.
The main reason for the emergence of this trend is to reuse old or broken roofing slates so it has an ecological aspect. If they are to be used in paving, they have to be set into the ground so that the top edges are flush with the paving surface. This can be made easier by cracking the slates in half; the added benefit of this is that it will make the slates go twice as far.