Building into an earth bank.

Hi,
I intend building an out house in my garden. I will be digging into an earth bank and building a retaining wall on two sides to make room for the out house. The retaining wall will be about six feet high at its highest point. The building will only be used for storage but I would like to make it as damp proof as possible. If I use the retaining walls on two sides as part of the construction of the out house how can I make them damp proof?
Kind regards, Baldrick

you could try cetco voltex
look at www.bluebaybp.co.uk they are suppliers of all kinds of damp proof items

Going off what Mike Homes does on the TV, they seem to coat the brickwork with damproofing gunge then put a membrane on & coat it again to stop water penetration.

Then put a layer of stones between the wall & the earth with a drainage pipe.