Rendered walls and damp!

[Lavendersquare]

Bought a beautiful house a few years back, it's completely rendered and the render is painted with something like Sandex. It looks beautiful and very stylish, nothing untoward showed up on the survey.

However I've noticed that some of the paint has flaked off which I thought was because it was near the boiler hot air outlet. On closer inspection it seems as though the wall under the paint is wet to the touch and I suspect that it's damp. This particular external wall isn't part of the living accommodation due to the house being three storeys, this wall is for the garage, but damp rises so I'm worried.

Since finding this issue I've read up on render and found that damp can be an issue, so I really need to get it looked at quickly.

Who would you approach for advice? I don't just want to ring a builder so should I get a surveyor? I say a surveyor but DH thinks this is over the top, but if the house needs work it's likely to be expensive and I don't want to get it wrong and have to do it all again in a few years.

Anyone have experience of something similar?

The cost of a survey could go towards the repair. I would contact a renderer for a quote and go from there. If it's one patch it shouldn't be to expensive to repair

No advice but ours is the same. We have a rendered gable end wall which is freezing and damp to touch. We have tried everything over the years and nothing makes it better.

We’ve got the same problem too. We’ve been trying to get someone since last year but it’s an old listed building so no one seems to want to touch it plus need planning apparently

It’s probably just the water vapour from your boiler flue condensing on the cold wall. If so, changing the type and direction of the flue terminal would likely solve it.

Share some photos of the damp patch, in context? What type of boiler is it? Any sign of a damp patch inside the garage? How old is the house, roughly? And do you know what the render material is - e.g. lime or concrete?

You say that you suspect damp, however damp itself isn’t a “thing”. It’s just a symptom of water where there shouldn’t be water. You simply have to stop the unwanted source of water and your damp wall will dry out.

First of all, rising damp is a bit of a myth, so don't worry about that. It's not going to creep up into your living accommodation.

It is almost certainly, as a pp said, being caused by condensation from the boiler outlet. Do what they suggested and change the flue first, then wait a few weeks to see if that fixes it.

The thing with damp is to try one thing at a time, see if the problem is solved and then move onto the next possible solution. You don't need a surveyor yet.

Thanks for the replies maybe DH is right and we don't need a surveyor or hacking off all the render just yet.

Ironically DH works at a firm loosely connected to the building trade so he's going to ask a colleague to recommend someone to have a look.

If the render touches the ground, the damp could be rising.

Render should start above the damp course.

We have very old roughcast- a form of rough-surfaced render, a bit rougher than modern pebbledash. It too is painted. Most of it is nearly 100 years old and is fine. There is only one significant loose patch on the whole house- exactly where our predecessors had a built-in oven on the inside. When we removed the oven and the chipboard behind it (that was on the wall instead of plasterboard (don't get me started on that) there was a missing brick behind it. Steam from the oven was getting into the cavity , right where the render is loose. I doubt it's a coincidence.
I suspect it may be the case that steam from the boiler may be to blame for your problem, in which case, sorting out the flue may well be all that's needed- then when it's all dried out, you can just have the render patched.

Do you know what’s under the render, OP?