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Posted: Mon Jul 21, 2003 5:18 pm
by 104-1093880317
I have an old driveway getting replaced (myself). I have excavated the top surface and exposed the sub base. I haven't removed any more subbase than I could, but the top of the sub base is uneven and full of rocks (up to 15 cm). Do I compact this first having levelled as I best I can before laying sand. How level do I need to be at this stage (i.e. before the sand?).
Posted: Tue Jul 22, 2003 11:27 am
by 84-1093879891
The sub-base needs to be fairly accurate - the usual standard required is +20mm or -15mm. Hoiwever, if there are 'big rocks' on the surface of the sub-base and they are protruding, they really should be removed and the surface of the sub-base regulated to give an even surface with no big lumps in it.
If you leave these ;umps in place, they profile can be reflected through to the surface of the eventual paving, and so, in a couple of years, you might find that some individual pavers were more prominent than their neighbours, or were proud and rocking becaus ethey were placed directly over these 'lumps' which have provided more resistance to consolidation than other parts of the paving.
As I say over and over again: the sub-base is the strength and integrity of a block paved driveway and skimping on it is a false economy.