Damp Spot Dining Room

[Poisonata]

Hello all,

I have a damp patch in one corner of my dining room approx 45 cm in height and 30 cm across on a single skin internal load bearing wall. The dining room wall side is plastered, the other side (under the stairs) is only painted. House is 'Kettering Brick' end of Terrace (built 1890).

The advise to get rid of this problem was to apply a layer of damp course treatment to the few bricks on the painted side (under the stairs) by drilling a hole into the centre of each one and allowing a bottle of damp course treatment to soak into each.

Bearing in mind we are only talking 6 or so bricks here, I was hoping to avoid the expense of hiring a damp course injection machine.

My two questions are:

Is the above advice correct ?

What product should I use for the damp course treatment ?

Although the damp spot isn't a huge problem it has started to damage the plaster. Before replastering I was hoping to rectify the problem without a huge outlay.

Many thanks in advance to anyone who takes the time to reply to this post.

Regards, Norton.

 

[JerryM]

given that you have got damp in 1 area I am surprised that there isn't damp in the rest of the house. walls can still be damp without being visible.

ideally a meter is needed to check for sure. you could stick squares of plastic onto the other walls, leave for 24hrs. any moisture on the inside indicates damp.

the cause of the damp needs to be established. from the description is sounds very much like rising damp - particularly as it's on an internal wall. if there is damp elsewhere then it could also be penetrating (water passing through the brick from outside or from inside plumbing) or condensation (not enough vent during/after cooking, washing etc).

ideally you should get a survey from a damp company (just from 1 to start with to get an idea) which should be free and no obligation.

just focusing on the single patch then i myself would probably go for injection of chemical dpc. for me this would involve drilling 2 holes per brick 3" deep and using a pump to force liquid into the bricks under high pressure.

there are a few difficulties associated with this. if it's a party wall then there is a legal requirement to get the neighbours consent. this is usually ok to get but if tricky neighbour then i would go for tanking not drilling. the treated wall may also need "isolating" this involves drilling & injecting vertical holes to stop damp getting into the brick from abutting walls.

assuming the wall is injected then unfortunately that's not sorted everything. rising damp causes "salts" to rise from the foundation soil through the brickwork and into the plaster. the existing plaster will be full of them and ideally (technically correct) needs hacking off and then rendering and replastering (that is what i would do). the salts are what's called hydroscopic which means they absorb moisture from anywhere and will suck up water from the air in your room and the wall will stay damp.

an option would be (which i don't really recommend) to apply a sealer to the wall so that the damp patch is not visible albeit the damp will still be their.

if your are taking the plaster off and the damp is only local to area then a paint on damp proof membrane might just do it (wickes have one which would give you a better idea). my only concern being that damp has a tendency to move if its original journey is interrupted ie by the membrane. the damp could then extend beyond the area treated. ideally at least 1m either side of the patch should be treated.

any clarification just ask.