In designing a new home with a concrete slab do not step down the slab to accommodate slate tiles. This only incurs extra needless expense. The ideal surface to receive slate flooring is a concrete slab finished accurately to falls and surfaced with a wood float finish. Do not use curing agents. Wooden floors can also provide a perfect surface to receive slate flooring providing they are of sound construction.
Method of installation
For laying over timber floors involves the laying of a rubberised bitumen membrane reinforced with a layer of hessian direct to the wooden floors. Slate is then laid the same as with concrete floors using adhesive, grouted with grout and sealed if necessary with Slate Sealer.
Sealers
There are available two separate types of sealers -
Matt finish - this is an acrylic base sealer designed to be absorbed into the slate to provide a wet but matt finish.
Gloss finish - this sealer forms a film on top of your slate providing protection against staining. It is recommended for use particularly in kitchens to combat grease and fat stains.
These products are designed only for use with slate and are guaranteed to provide the optimum performance from your slate flooring. The best sealer for outdoor work is one with an ultra-violet filter.
When applying it is important that the sealer be applied as thinly as possible in order to prevent build up. It is far better to apply two thin coats than one thick coat. Slate must only be sealed after laying and then only after the floor has been washed thoroughly and cleaned of all excess dirt and grit.
Floor Coverings 
