|
Hi Peter, I think that it depends on the ground your are digging into. The idea of a monolith under a pier is to curb vibrations especially in soft clay type soils. My ground is hard sandstone (had to use a crowbar) so I have been able to get away with a hole 600mm deep and about 400 x 400 wide. As far as bolts go I used these concrete screws to hold the pier down you just drill a hole in the slab and screw them in, easily removed and stronger than dynabolts.
Rick
|