Posted: Thu Mar 03, 2016 7:25 pm
Im extending my driveway and Ive dug down 200mm and got new my edging kerbs in place. Too my surprise when i started breaking out my existing edging kerbs, I found 80mm blocks sat on a 100mm concrete slab, and 100mm grit sand. When i put my type 1 sub base down, 40mm will sit next to the concrete slab, while the other 60mm will be next to sand. My 40mm laying course would then bring this level to the existing driveway. However I'm concerned about the mot going into the grit sand, Will this new sub base layer to go into the existing laying course causing the blocks to sink over time? Is there anything I can do?