The intention is to install a new 'crate in geotex' soakaway arrangement just over 5m from the rear of my property. This will accept water from two existing side outlet bottle gullies each collecting roof water run-off. Having carefully studied the Paving Expert site for minimum depth specifications for 110 mm plastic underground pipe, it seems that at no point will the pipes leading to the soakaway be at the minimum 600mm depth specified, especially at the gully ends where there is only c.80mm between the top of the pipe and the finished paving surface. FYI, I did consider the use of a gully risers but even these would not get close to the 600mm depth required.
Do I therefore need to encase the entire lengths of the new pipes in concrete, as the PE site describes?
you don't have to put pipes in at 600. whatever depth you can achieve you go with. if it is less than 600 in fields and 900 in road/drive you should consider concrete encasement.
Thanks. The pipes will be in a garden but more specifically, underneath a sub-base, cement and flag patio. Would this in any way affect the requirement for concrete encasement?