Encasing existing drains

[trumpetman]

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.

[seanandruby]

cut out the hole in your board making sure it will fit in the trench both ways, then cut it in half and feed bottom half under, concrete half bore making sure you push concrete under pipe with edge of shovel. You may find it easier to take out the pipes dig out, then concrete to underside of where bottom of pipe will be and relay.. Take levels first to refer to. Notwithstanding, put packers under pipe near to joint, brace to stop lateral movement, concrete as you go taking out supprts/packers. movement

[seanandruby]

hope it makes sense, i am limited to what i can reply because only got phone. At least it is only sand so should be an easyish dig, use a graft so that your trench isn't to wide, otherwise you'll be knocking up extra concrete. good luck.

[trumpetman]

Sean

Thanks for the advice, I'll give it a go. Sorry to show my ignorance, but what's a "graft"?

Steve

[msh paving]

a graft is a small narrow shovel, usual cut down from a big one or a ready made one ,like the shovel in this pix



MSH

[trumpetman]

Thanks MSH. Now I understand, makes complete sense...

I threw one of these away a few years ago that I used to use for digging up bait on Southport beach. Just goes to show that you should never get rid of anything! It always comes in handy eventually.

Thanks again.

[msh paving]

always handy even if you never use it........

[seanandruby]

My shed ,like any other is full of handy stuff we never use A good trenching shovel can cost well over a hundred squids.

[haggistini]

i might invest in 1 of these

http://www.orientexpat.com/forum....n-china