DAMP AND MORE DAMP

andybharris · Post by **andybharris** » Thu Apr 23, 2009 8:32 pm

HI all.
as a young first time home owner i am a bit stuck for ideas. I have damp and mould on my interior wall (this is an outside wall). the walls do not have cavity insulation as they are double skinned brick (old house), behind my skirting board was damp and my plaster board was soggy on the bottom behind the skirting board. the dcp was only half an inch below my drive way so i have dug that out to 15cm. the exterior wall is cement rendered on the side but the rear is painted brick and the pointing needs redoing. the main problem i have is the interior bricks above the dpc were very damp but the first row above this all have holes drilled in them what are these for as they are blocked dirt and muck inside. any ideas or advice to stop the damp much appreciated. Thanks in advance

stuart45 · Post by **stuart45** » Thu Apr 23, 2009 9:45 pm

Mould is often a sign of condensation. Holes just above the DPC could be a sign of chemical injection for a new DPC. Can you put on some photos of the wall, external and internal?

andybharris · Post by **andybharris** » Fri Apr 24, 2009 3:51 pm

stuart45 wrote:Mould is often a sign of condensation. Holes just above the DPC could be a sign of chemical injection for a new DPC. Can you put on some photos of the wall, external and internal?

Pics of the walls in/out, note how the dpc is below the drive in one of the pics and the first pic shows it all dug out

stuart45 · Post by **stuart45** » Fri Apr 24, 2009 9:27 pm

It looks like rising damp has been diagnosed in the past and a chemical DPC has been put in. The plaster should have been removed and replaced with a sand/cement render with added waterproofer/salt retarder. If this was not done any hygroscopic salts in the plaster would attract condensation and cause damp. Looking at the wall I would say that the internal needs hacking off and replastering.

Perry525 · Post by **Perry525** » Sat Apr 25, 2009 7:21 pm

T his is a classic case of people doing things without any thought to the possible consequences. From the time the property was built the garden has been raised and eventually covered in concrete.
The process needs to be reversed.
The concrete needs to be broken up and removed all round the house until there is a clear gap of at least nine inches high and 12 to 15 inches wide to ensure the rain does not bounce above the dpc and wet the wall.
Then the wall should be painted with silicone paint, to ensure the rain is shed rather than soaking in.
The pictures from the inside show that the chemical dpc was positioned too high and that the wall was plastered below the dpc causing the damp to rise round the dpc.
The best solution to this, is get on to e-bay and buy some cream dpc.
Then redo the dpc as close to the floor as you can, drilling into the mortar, making sure to drill down between the bricks, to carry the cream below floor level.
Damp rises through the air cavities that are entrained in the mortar, the
cream stops this.
Leave the wall uncovered, keep the room warm and the damp will gradually move outwards and be blown away by the wind.
The thing about damp/water vapour is that it is attracted to cold and left to itself will of preference move to the outside of the wall, where it is the coldest and then blow away.