We are currently renovating our garden, and one thing we will be doing is putting up a metal shed at the bottom of the garden.
The area where it currently is is an odd DIY structure the guy who owned it before made. It is sunk a meter or so below ground level, with a greenhouse like structure over the top. The bottom is always about 30-50cm deep in water with a metal gangway running along above the water level. I think the guy grew water plants in there originally.
My question is, as there seems to always be water in there I suspect he as made the base relatively impermeable to water to maintain the level. If were to just ill it in with rocks and then sub base would this impermeable layer roughly 1m below the level of the eventual metal structure cause any issues? We currently have a lot of material from digging out elsewhere in the garden and it would be handy place to put it but don't want to cause ourselves issues we need to solve further down the line.
Cheers.
