we're doing a driveway out of bluestone cobbles 5x5x10. The engineer has called for the cobbles to be set in stone dust, and underneath that 1.5 inches of stone dust, with a 6 inch layer of item 4. this over a well compacted sub grade.
Our contractor though suggests that we use 3/4 gravel with 2-4 inches of cement over that instead because he said that over time the item 4 will deteriorate and we will end up with tire depressions where we drive over the cobbles.
any thoughts on item 4 vs 3/4 gravel with cement? and with these cobbles which will provide the best base?
cement is expensive! so, we are wondering if it is really necessary and why the engineer did not call for it.
dl
Our contractor though suggests that we use 3/4 gravel with 2-4 inches of cement over that instead because he said that over time the item 4 will deteriorate and we will end up with tire depressions where we drive over the cobbles.
any thoughts on item 4 vs 3/4 gravel with cement? and with these cobbles which will provide the best base?
cement is expensive! so, we are wondering if it is really necessary and why the engineer did not call for it.
dl