Home DIY

He reckons if he just repointed it should last about 15-20 years, or thereabouts, but then it would start doing the same thing, so he's proposing a Damp Proof Membrane (DPM) made of bitumen, which will then be covered with masonry paint (more because it's black and I don't want black walls than anything else). Apparently this keeps the moisture in/behind the wall, and add considerably to the life of the pointing, which is why he thinks its a better option, and it will keep the cellar dry too because it traps any moisture behind.

My only worry about this was what happens if the water builds up behind this layer, but as he has pointed out an underground wall is always going to have moisture in it, and it's actually very dry for a cellar anyway, so I think I'm happy to do it this way.

I'm getting him to pour a new concrete floor too, and he's going to put a DPM under that too in case water ever came up from below.

I would be VERY wary of this builders suggestions, they are likely to introduce far worse problems than they seek to solve.

There is a huge knowledge gap within the building trade when it comes to working on old houses - applying modern building techniques and materials to old houses can be a recipe for disaster.

A lot of good info here: http://www.periodproperty.co.uk/discussion_forum.htm