For many hundreds of years random sized slate walling has been used to create walls in gardens, as perimeters around the countryside of the Lake District and as features in residential homes, such as for fireplace, or as an exterior facade.
The material we supply has been carefully selected to provide slate that generally has a flatter face to allow for bedding, but every piece is still random. In all projects, large or small the first task is to sort through the stones to visualise how each will best fit together to create the type of effect seen in the pictures. If you are laying as a face to a garden wall or fireplace there will normally be a rigid inner block wall, the width of which will depend upon the height, but typically because the slate pieces are random for a wall up to 450mm in height, a concrete block of 100mm in width will suffice but increase this to 140mm for walls up to 1.2m high. For higher constructions, we would recommend advise from an architect or structural engineer, who will take into account the prevailing ground conditions and slope. Walls must be built on a solid foundation, which is typically a concrete strip footing, using a semi-dry mix. This should be approx 100mm wider on each side of the wall you intend to build.
Once the inner skin to the wall is built the random slate will be build up and secured using a normal 3-1 mortar mix. This is normally laid from the back of the stone to approx 50% of the piece width to bed it into the course below, and where possible occasionally tie into the inner skin of the concrete blocks. The also means that the mortar is hidden to give the illusion of a dry lay.
The wall will be capped off using a stone slab or the walling pieces as cross headers.