building a base room

[arfa]

i am thinking of building a base room in my garden. However i know from a previous extension that at approx 800mm i will encounter a gravel stream and also the top of the water table. Does anyone know how to build into gravel and overcome the subsequent drainage problems and if it is indeed possible.

[Perry525]

Have a word with your local Council, they are dealing with this problem every week and they will tell you what they require.