Flaking shale step slabs
We had stone slab steps installed for the two walkways to the front of our house, 3 sets, 4, 2 and 2 steps, most approx. 4 ft by 7 ft., about 5.5 in thick. When they were done, it looked great.
The set of 4 are of slabs of shale. Since the install, about 2 months ago, the shale ones have been flaking away at a rate that is disturbing leaving chunks of the slate by the steps and with loose pieces of shale working their way off from the slabs. The installers said it was "no problem," would stop soon, and offered to come and "hammer off" the loose pieces, but there has been more than a bit of avoidance by them since that suggestion and no action.
From the face of the steps (I'd guess I should call these the risers) we can see the striations of the layers.
Will this continue? Should we be asking for a different type of stone slabs to be installed?