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Groundwork & Foundations Question
Building concrete shed base on very wet ground - porous or non porous sub base?
I've dug out an area approx 2 metres by 3 metres ready to pour a reinforced concrete shed base but discovered the neighbour has put a soakaway crate right up against his side of the boundary which takes all the water from his paved over garden making the ground very wet.
On the boundary side I decided to dig down further about a metre to see if I could block the water coming from his side (digging also revealed an old concrete path that was covered over so only the side to the boundary is this deep). The soil is very clay like and after a night of rain I now have a metre deep pond which has been there for days. I have spoken to the neighbour and he won't do anything about and I don't wish to get into a dispute so would rather work with what I have.
I am wondering whether to drain with a pump and wait for a stretch of dry weather and fill with a porous aggregate to take some of the water or pack a non porous MOT aggregate and put a damp proof course below the final 15cm top layer forcing the water to run elsewhere. The shed is about 600Kg so I want it to be as sturdy as possible.
Pumping out the excess water and putting a pourous sub-base with a polythene membrane base and sub-base to stop rising damp/water. Hope this helps.
Answered 6th Jun 2018