Published on November 12th, 2016 | by Henri0
Keeping bluestone slab from heaving
Q. I have a 10×10-foot bluestone slab at the entrance to the house. The base is a cement 3 to 4 inches thick, with stone dust under the bluestone. The spaces between the blue stone slabs are filled with polysand.
To stop the frost heaving, what about drilling a series of holes in the cement slab and inserting plastic tubes to allow the water to drain below the frost line? Or your recommendation? Thank you.
A. Are you having frost heaves that lift the bluestone slates now? If not, I think drilling holes to drain water below the base slab would make it worse by dumping water into the stone dust with the potential for frost to heave the base slab.
Instead, consider replacing the polysand with cement properly tooled to be waterproof.by