Damp Single skin wall

[Hunterlit]

We have an external wall in our kitchen that is very damp. I have measured the height of the wall both outside and inside, and the ground outside is roughly 300mm higher than inside. It is a single-skin brick wall. I'm going to hazard a guess and say that at some point, the ground outside has been raised and has bridged the DPC. My plans are:

1. Create a channel outside with a DPC membrane in the channel, lapped up to the wall and finished with gravel. My partner isn't keen on this idea.
2. Use Dryrods from inside, below the ground level outside.

Number 1 is my preferred method, and I'm a bit hesitant about using a liquid DPC because some people say they don't work. Also someone has repointed parts of the wall with sand and cement instead of lime, which I think may be causing issues; however, I don't believe it is causing as much of a problem as the ground level being raised.

 

[Orifice]

There is an element of "snake oil" with things like dryrods. Ultimately you're not addressing the root cause unless you drop the ground level below the DPC

 

[Trifid]

Why don't you think it is condensation? Single brick walls are very cold on the inside and kitchens are humid places.

 

[ChroniC]

As the above poster said. You have two problems. You either have rising damp or condensation from the temp.. If your getting black mold all over the wall it's very likely condensation. If it's damp patch rising from the bottom them it's the DPC...

The only thing imo you can do to insulate a single skin is to cover the wall with some celotex and plasterboard, but I'd hazard a guess if it's in a kitchen you have cupboards/work surfaces on it, so that's gona make life harder.

You could probably tell the difference by getting a water meter thingy and testing if the brick is absorbing water. If the bricks dry but your getting mildew, it's really a condensation thing.

I have had similar and you'd be suprised how much difference good ventilation or radiators in the right place makes. Open the window and let the boiling water out, otherwise it's gona stick to the cold surface.

 

[danlightbulb]

I think a single skin wall below ground level is just going to suck water through from outside. Can you lower the ground level outside and find the level of the dpc? If the internal floor is 300mm lower than external then the dpc is probably even lower than that, if there even is one in this wall (can you see one from inside?).

 

[fastwunz]

It’s because it’s single skin and the ground levels externally are too high- it’s that simple. Ignore your wife and do what you said - the ground level externally should ideally be 2 brick courses below the internal threshold.

Single skin walls will be freezing,. Consider internal wall insulation to the wall once you have sorted the damp.

 

[Hunterlit]

It’s because it’s single skin and the ground levels externally are too high- it’s that simple. Ignore your wife and do what you said - the ground level externally should ideally be 2 brick courses below the internal threshold.

Single skin walls will be freezing,. Consider internal wall insulation to the wall once you have sorted the damp.

Yes, this is what I have decided to do lower the ground level and go for a french drain. I have considered insulation, though it is on the back burner for now.

I think a single skin wall below ground level is just going to suck water through from outside. Can you lower the ground level outside and find the level of the dpc? If the internal floor is 300mm lower than external then the dpc is probably even lower than that, if there even is one in this wall (can you see one from inside?).

No DPC is visible from the outside. I don't think there is one, so I will most likely add a liquid DPC of some kind

Why don't you think it is condensation? Single brick walls are very cold on the inside and kitchens are humid places.

Definitely not condensation. Only the lower part of the wall is affected, more so at the bottom, and then dampness has tracked up the plaster for 10 to 15 inches.