I have a conservatory which has been built to close to the adjacent neighbours garden (in effect underground). In heavy rain, water enters it at DPC level.
There is no access to the exterior wall so I have stripped the internal skin off the wall. I have been advised to paint a latex and cement solution on the inside similiar to tanking a cellar, I have found a solution on the net called NB1, is this the same as SBC? although another builder recomends asphelt damproofing which is more expensive.
could a gully be put in the cavity? and how would the water be pumped out? has anyone got any advice?