I've just got planning permission for my sister-in-law for a two storey rear extension to their house. They're just getting prices from builders and one builder who has been to look at the project has told them that he strongly advises that they build the walls with two adjacent skins of concrete block, then an insulated cavity and then the external skin of limestone. He's told them that as Limestone (the outer skin) is so pourus they'll get damp problems if they don't use a double skin of blockwork.
Firstly, does anyone know if using a double skin of blockwork would help prevent damp?
Has anyone ever built a cavity wall with a double blockwork skin on the inside so prevent damp?
Is the builder trying to increase his time he's on site while work is a bit slack?
Most of the work we are involved with is built from either Limestone or Gritstone and as far as i can recall we have only once specified an inner skin of more than 4inch block once when the client specifically wanted thick wall. I personally have never heard of any of our clients having damp problems from single blockwork skin walls, certainly where the walls have not been retaining walls anyway??
Firstly, does anyone know if using a double skin of blockwork would help prevent damp?
Has anyone ever built a cavity wall with a double blockwork skin on the inside so prevent damp?
Is the builder trying to increase his time he's on site while work is a bit slack?
Most of the work we are involved with is built from either Limestone or Gritstone and as far as i can recall we have only once specified an inner skin of more than 4inch block once when the client specifically wanted thick wall. I personally have never heard of any of our clients having damp problems from single blockwork skin walls, certainly where the walls have not been retaining walls anyway??