drains are where foundation is to go???

[matt73]

existing drains that are not to be moved are in a place where the extension will be built. it is planned to be a trench fill type foundation.
this will mean the drains (existing) will have to pass right through the concrete.

what is the correct way to do this, which should satisfy building control. ie what is the correct way to protect the drains?

thanks guys.

 

[noseall]

if the drain passes through the foundation then you can either stop the concrete either side of the pipe using shutter boards and p.c.c lintel over, or b.c. sometimes let you wrap "compressible" material around the pipe, usually firbreglass insulation. if the pipe runs along the trench or across the corner of the building, then you need to consult b.c.

 

[matt73]

good man thanks very much...

what sort of lintel would do. the trench is to be 450mm wide. would you just leave the shutterin in and pour away?

matt

 

[noseall]

make sure the shutter boards are no less than 18mm thick, preferably ply or o.s.b., and use plenty of props between the two. best to remove the props when concrete has set, just in case you need to work on the pipes. keep the shutters the same height as the concrete and leave em in. pre-cast concrete builders lintels will suffice.

 

[matt73]

sorry last q.

should the shuttering be the same depth as the concrete. ie, if the trench is 1000mm deep and i am pouring 750 of concrete does the shutteriung run from the bottom of the trecnh all the way to the top ie 750mm of shuttering
or
do i stop the shuutering at the top of the pipe and put the lintel over then pour on top of lintel

thanks

 

[noseall]

the shuttering is fitted from trench bottom to concrete top, in other words you will have a 450mm slice of concrete missing from the trench.

 

[matt73]

sorted

ta

 

[Static]

Using a compressible material (approx 50mm surround) around the pipe is more preferable, unless the pipes are too high or too low in the footing.