Damp on internal wall?

[Tentontousand]

I can't work this out but we seem to have what seems to be damp on an internal wall corner between our living room and dining room. It's no where else in the house so I can't work out why there would be damp here. The wall used to divide two rooms but in the past was knocked through to open up the space. The plaster below it (not painted) where skirting was doesn't feel damp to touch though

Is this damp or could it be something else?

 

[Mike13]

the internal dpc has been bridged near the end of that wall, at the very bottom where the skirting used to be you need to clean off the plaster back to the brick. The damp should then slowly clear. there is a special plaster for use near the dpc, but possibly not worth buying a whole bag for a small fix.

 

[foxhole]

Was that previously an external wall? I would be looking to roof for problems, penetrating water will travel down till it hits dpc and then accumulate until it finds a way out .

 

[Tentontousand]

Was that previously an external wall? I would be looking to roof for problems, penetrating water will travel down till it hits dpc and then accumulate until it finds a way out .

No, existing internal wall between two rooms bang in the middle of in a Victorian home. Just been knocked through in the past. No signs of the same damp patch anywhere else it seems

 

[opps]

I am not convinced that it is damp. I don't understand why it would rise so high but not travel outwards.

The plaster behind the skirting shows no signs of damp.

I may well be wrong, but I think it may be some kind of contaminant, eg cooking oil.

That said, there is some evidence of rust on the angle bead.

If you decide that it is damp, you could drill and insert Dry Zone rods

 

[Tentontousand]

I am not convinced that it is damp. I don't understand why it would rise so high but not travel outwards.

The plaster behind the skirting shows no signs of damp.

I may well be wrong, but I think it may be some kind of contaminant, eg cooking oil.

That said, there is some evidence of rust on the angle bead.

If you decide that it is damp, you could drill and insert Dry Zone rods

Yeh I'm a bit unsure too... if it wasn't and just contamination, would I just need to sand it all back, prime and repaint?

 

[opps]

Yeh I'm a bit unsure too... if it wasn't and just contamination, would I just need to sand it all back, prime and repaint?

Difficult to say, if you can apply a small amount of emulsion over it and it passes the fingernail test the next day, then any old stain blocker should be OK.

 

[Tentontousand]

Difficult to say, if you can apply a small amount of emulsion over it and it passes the fingernail test the next day, then any old stain blocker should be OK.

I'll try that out. Will also cut back some of the plaster just in case. Cheers all.

 

[foxhole]

No, existing internal wall between two rooms bang in the middle of in a Victorian home. Just been knocked through in the past. No signs of the same damp patch anywhere else it seems

Does the wall go to roof at first floor level?

 

[Tentontousand]

Does the wall go to roof at first floor level?

no, it's ground floor with another level above, then the pitched roof space.

 

[foxhole]

no, it's ground floor with another level above, then the pitched roof space.

Yes , but is there a wall directly above that one?Or a bathroom or toilet?

 

[Tentontousand]

Yes , but is there a wall directly above that one?Or a bathroom or toilet?

yeah it's load bearing so another wall straight above it. No bathroom or toilet connected to these walls though.

 

[JohnD]

Is there anything in the room above that contains water?

Have you looked under the floor next to the damp patch?

 

[Tentontousand]

Is there anything in the room above that contains water?

Have you looked under the floor next to the damp patch?

only thing I could think of would be CH pipes but theres no leak, boiler hasn't lost any pressure.

Floor next to it is concrete/screed and thats bone dry

 

[mrrusty]

I think the clue is that it appears to be travelling up the wall corners where the metal strip is, and not horizontally which is what you would expect if it was coming from the ground. Is there a draught/air circulation in this area? get an infrared thermometer and see if this is a cold spot. If it's a few degrees lower than the surroundings, then you have a possible reason/solution.

I have seen similar in our house next to a fridge with a bottom fan. Obviously a humid area because of the fridge defrost mechanism evaporating the melted ice on defrost, and the fan was circulating the moist air past a cold wall nib just like this, which continually caused condensation.

Just to add, we have a large opened up fireplace, the back wall of which is exposed brick and the party wall to next door - 9" thick brick wall. That wall goes down to ground level. Using my own infrared just now, the base of the wall inside the fireplace is fully 2 degrees cooler than the upper area of the back fireplace wall, which illustrates how the wall closest to the ground is a cool spot and losing heat in to the ground, even though it's in the middle of the house. If there is a condensation risk due to the humidity and dew point, a 2 degree cool spot would be more than enough to show up localised condensation.