sinking drives

[sprint bluesman]

I want to renew my drive with block paving but I am dismayed at the number of drives that have sunk in my street. My friendly contractor has suggested block paving on a bed of sand laid on 5" of pav1 concrete. Is this sound advice or am I being lead up the garden path?

[84-1093879891]

A concrete sub-base (what we call CBM) can be used, but, in all honesty, if block paving is laid over a properly constructed flexible sub-base, then there should be no problem with settlement or channelisation.

There is a page on the main website dealing with laying blocks over a rigid base that you should read to give you a fuller understanding of the issues involved. Personally, I think that a CBM sub-base is massive over-engineering for most residental projects and is sometimes use as a 'get out' by contractors and builders who don't properly undestand the principles involved in pavement construction. If there was some problem with the ground in your area - perhaps it was notoriously unstable, marshy, or made-up ground - then a case can be made for a CBM sub-base, but their usual role is beneath paving in fuel station, bus stations, taxi ranks and other heavy-use applications, not private driveways.

Having said all that, if CBM is what you want, then there's nowt wrong with it - apart from the extra cost.