Posted: Thu Aug 18, 2011 8:05 pm
I need to relay my driveway as the existing flags have moved quite a bit. I checked how they were originally laid and found they were just put on 300mm of building sand, which explains why they have moved...
I have also found a plastic surface water pipe just 300mm below the existing flags. Reading the main site, it looks like I will need to encase this in concrete (lean mix?) 100-150mm all round, with compressible board at the joints, and then use mot1 and sharp sand for the sub-base and bed. Sounds easy, but how do I get the compressible board around the existing pipe? Laying a new run I guess you cut a round hole and slide it on the pipe, but I don't want to disturb the existing pipes so I can't do that. Also, how should I support the pipes before I pour the concrete? To get concrete all round, I will need dig out all round the pipe and leave it freestanding. If I can get the board on, will it act as a series of supports?
Thanks for the help.
I have also found a plastic surface water pipe just 300mm below the existing flags. Reading the main site, it looks like I will need to encase this in concrete (lean mix?) 100-150mm all round, with compressible board at the joints, and then use mot1 and sharp sand for the sub-base and bed. Sounds easy, but how do I get the compressible board around the existing pipe? Laying a new run I guess you cut a round hole and slide it on the pipe, but I don't want to disturb the existing pipes so I can't do that. Also, how should I support the pipes before I pour the concrete? To get concrete all round, I will need dig out all round the pipe and leave it freestanding. If I can get the board on, will it act as a series of supports?
Thanks for the help.