Drainage pipe/soakaway bedding - 10mm gravel vs grit sand

[Mikey_C]

i'm putting in a crate based soakaway and associated pipe feeding it. the installation guidelines for the crates say you can use grit sand or 10mm gravel for the 100mm surround.

Could I use grit sand for the pipe bedding as well?

The reason why I ask is that I have the patio that is feeding the soakaway to lay, therefore I could get one large (7Ton) delivery of grit sand rather 3.5 of pea and 3.5 of grit.

Anything I need to be aware of if using grit for the pipe bedding?

[lutonlagerlout]

i wouldnt use grit sand around pipes mikey
10 mm shingle all the way
LLL

[flowjoe]

Theres been some debate on this in the past and granular fill is the usual recommendation.

If your digging in a clay and use a granular fill there is a good argument that you are creating a water course around the pipe itself which could lead to soil erosion in the future, but at the same time a course sand pipe surround could liquify and be useless as far as supporting the pipe work goes.

[Mikey_C]

its a 3m run going straight from the channel drain into the soakaway, in free draining sandy soil. However I think I knew i should be using 10mm, might just use it round the pipe work which means I can probably get away with buying it in 25kg bags which are easy enough to transport.