QUESTION

Is Slate Suitable for a Driveway? I am in the process of designing a new driveway and walkway to the front of a home. We've used slate and the rear yard patio using irregular shapes of slate with grass in between. It looks beautiful, and the homeowner would like to use the same idea on the drive. I'm worried that the slate is too soft and will break under the pressure of the car. Can you advise as to whether my concerns are valid?

ANSWER

ANSWER - Most slates are considered hard and dense, but it varies depending on the type and source. Slate is a layered material so it can flake but is normally sturdy.

A good quality slate will work on a driveway if it is installed correctly and attached well over a concrete substrate with no voids under the stone.

All stone can be sensitive to prolong exposure to moisture and should be protected from the moisture with moisture barriers under the concrete slab and at their edges adjacent to landscape. Normally slates are low absorption so you must verify it is freeze thaw stable. Make sure there are problem expansion joints placed every 8 feet in each direct. Good Luck!