ColJack said:
my brother bought a house which had a damp problem..
he had a chemical DPC put in to fix the old one..
no other remedial work was carried out, not drains installed, no gutters replaced or even cleared, no render replaced etc..
the only other work carried out was done a few weeks later once the walls had dried and several patches of plaster had to be replaced because the damp had caused them to blow.
OK - now we're getting somewhere. May I ask you some more questions about this, so that I can understand why your brother has the only house that someone is willing to put forward of an example of a property that had rising damp through the brickwork?
1. What was the ground level outside the damp wall, relative to the old DPC?
2. What was the ground level outside the damp wall, relative to the new DPC?
3. What was the internal floor level, relative to the old DPC?
4. What was the internal floor level, relative to the new DPC?
5. What type of ground was outside the damp wall?
6. Had the house been unoccupied for any period of time before he moved in?
7. If so, for how long, and at what time of year?
8. Which direction was the outside of damp wall facing?
9. What area of the country was this?
10. What was the construction of the damp wall?
11. Did it have a cavity?
12. Was the wall rendered, or covered by any means, on the outside?
13. If so, what was the state of repair of that covering?
14. Did it have any insulation in the cavity?
15. How old was the house?
16. What was the construction of the floor next to the damp wall?
Softus said:
dano1779 said:
what you're telling me is that all the houses that are built don't need a damp course because no water will rise up?
Where have I told you that?
here..
Softus said:
Some people believe that the DPC prevents damp from rising through the brickwork, but this is a myth.
You've misrepresented my post, possibly even deliberately. Preceding that statement was the following:
I clearly said:
The DPC is a thin (around 2mm) layer embedded between two specific courses of bricks, that is contiguous with the DPM (damp proof memrane) installed inside the house. Some older houses don't have a DPC, and/or a DPM.
And you've also omitted the sentence that followed it, viz:
I also said:
All damp problems at the base of a wall are caused by water falling/dripping/trickling from above or water bouncing off ground that is too high and/or too hard and/or too near.
To be clear on this point, a DPC is useful only when it's contiguous with the DPM. In theory it's possible for a badly installed, or unnecessarily installed, DPC to do more harm than good, by causing water to be retained in brickwork that would otherwise drain out, or by deflecting it to the inner surface of the wall.