Dear PPUK forum members,
I have only recently discovered this site and just joined this forum, so pardon me if I get any etiquette wrong.
The specific problem we have is as follows:
The house is built into the hillside, so that one otherwise external wall is buried in earth up to a level of around 1500mm above inside floor level. I have read the FAQ items on this website that deal with damp in all its various forms, but unfortunately we cannot do the obvious thing (remove earth from outside the house and lower the ground level) because we do not own the ground right next to the house. We have either got city council-owned pavement right up against our house, or we have the neighbour's house, which in fact appears to be built partly on top of our former external wall.
We have therefore got what I believe is penetrating damp coming through the wall because of the high ground level outside, which we cannot change. Having said this, most of the wall that is below ground level is actually built of some hard grey stone (possibly blue lias??) which is doing a very good job at keeping out moisture. Sometime in the past someone cut away a c.1300mm section of this stone wall, to insert a possible kitchen/scullery range (now itself long gone) and replaced the stone with brick. It is in this section that we are getting small amounts of damp.
Now we want to put a new solid floor down, to consist of stone flags/tiles with underfloor heating. The builder has told us to run a DPM all over the floor area, right the way up to the base of the wall, plus to fit 50mm of cellutex insulation and a layer of cement, before laying any new stone tiles.
The key question for is therefore: Is this going to make the damp coming from the ground outside the wall worse?
Someone before us has already partly rendered the wall to about 1000mm height with relatively modern cement, so there's not a lot of breathability anyway. Plus, because of the high ground level, the wall is constantly damp on the outside anyway. The present floor is a dreadful hotchpotch of about a third area covered in flagstones (about half of which are broken), and the remaining two-thirds of floor is cement poured on the subsoil (with a redundant lead pipe embedded in the cement), the whole thing sloping by about 40mm over 2000mm. The other external wall is above ground level (faces the garden), but appears to be single-skin brick with horizontal timbers which are a bit like wall-plates inserted every 2 ft or so between courses of brick; also this wall looks like it is built on top of the remains of the flagstones that once formed the floorcovering inside - definitely no slate or bitumen damp proof course in sight. However, the outside of this brick wall can apparently breathe, since according to the previous owners they painted it in microporous paint (which begs another question: how breathable are microporous paints?).
I'd be grateful for any help concerning putting a DPM all the way over the floor, thanks. Irina
I have only recently discovered this site and just joined this forum, so pardon me if I get any etiquette wrong.
The specific problem we have is as follows:
The house is built into the hillside, so that one otherwise external wall is buried in earth up to a level of around 1500mm above inside floor level. I have read the FAQ items on this website that deal with damp in all its various forms, but unfortunately we cannot do the obvious thing (remove earth from outside the house and lower the ground level) because we do not own the ground right next to the house. We have either got city council-owned pavement right up against our house, or we have the neighbour's house, which in fact appears to be built partly on top of our former external wall.
We have therefore got what I believe is penetrating damp coming through the wall because of the high ground level outside, which we cannot change. Having said this, most of the wall that is below ground level is actually built of some hard grey stone (possibly blue lias??) which is doing a very good job at keeping out moisture. Sometime in the past someone cut away a c.1300mm section of this stone wall, to insert a possible kitchen/scullery range (now itself long gone) and replaced the stone with brick. It is in this section that we are getting small amounts of damp.
Now we want to put a new solid floor down, to consist of stone flags/tiles with underfloor heating. The builder has told us to run a DPM all over the floor area, right the way up to the base of the wall, plus to fit 50mm of cellutex insulation and a layer of cement, before laying any new stone tiles.
The key question for is therefore: Is this going to make the damp coming from the ground outside the wall worse?
Someone before us has already partly rendered the wall to about 1000mm height with relatively modern cement, so there's not a lot of breathability anyway. Plus, because of the high ground level, the wall is constantly damp on the outside anyway. The present floor is a dreadful hotchpotch of about a third area covered in flagstones (about half of which are broken), and the remaining two-thirds of floor is cement poured on the subsoil (with a redundant lead pipe embedded in the cement), the whole thing sloping by about 40mm over 2000mm. The other external wall is above ground level (faces the garden), but appears to be single-skin brick with horizontal timbers which are a bit like wall-plates inserted every 2 ft or so between courses of brick; also this wall looks like it is built on top of the remains of the flagstones that once formed the floorcovering inside - definitely no slate or bitumen damp proof course in sight. However, the outside of this brick wall can apparently breathe, since according to the previous owners they painted it in microporous paint (which begs another question: how breathable are microporous paints?).
I'd be grateful for any help concerning putting a DPM all the way over the floor, thanks. Irina
