Condensation?

[Sikes]

Hi

Two years ago, my living room walls were taken back to brick. Recoated with cork insulation and then finished off with lime. Then painted over with Earthborn clay paint. In the last few months spots have appeared (see image). They are appearing on internal and external walls. I assume they are condensation, as they are only appearing 3ft from the floor upwards. Am I right in thinking this or could it be something else?

 

[pterodroma]

I believe you are correct, but it is mould, the growth of which is enabled by condensation.

I am starting to suspect that Earthborn paint is particuarly receptive to mould growth though. I have the same issue as you, but I am not suffering similar problems with other paints on surfaces that should be just as susceptible to it...

FYI, it will wipe off with a damp cloth for a quick 'aesthetic' fix, but the spores etc will remain.

 

[malcolm]

I would have expected condensation to be evenly distributed rather than blotchy. Though mould growth would likely start off blotchy and that needs moisture to get going. Above 3 feet seems odd. Normally the walls are wetter below 3 feet.

You could get some confidence by buying an infrared thermometer and a room temperature with humidity meter. You can calculate dew point temperature from air temperature and humidity near the wall (search dew point calculator), then if the infrared thermometer reads the wall at a lower temperature then it's probably condensation. If the wall is much hotter than the dew point temperature you can probably rule condensation out. Worth doing the measurement when you expect maximum humidity - ie if you dry clothes in the room. Is there something that could let a lot of moisture into the room?

 

[elizabeth]

Hello Sikes,
I had the same problem. The wall was lime plastered and lime washed and after a while I thought of trying Earthborn paint for a new colour. A few years later the same blotches as in your photo appeared, some as high as 5ft. I took photos and went and checked my paint tin but nothing seemed obviously wrong with the paint.
In the end of last year, I used a fine scrapper and scraped the paint off. It was impossible to sand off as it went incredibly shiny like glass. I will need to do a skim/top coat over it at some stage as it was difficult to leave no dents but the wall has been fine ever since - no signs of damp or condensation marks. The room does have fairly higher humidity but it is not damp.

 

[steveb]

Interesting. Earthborn clay paint here same blobs all over the walls behind furniture and in corners, so in the classic 'low airflow' locations.

I wonder too if something has changed as my last house I had no problems in 10 years whereas this has gone to rats in 2

 

[pterodroma]

Interesting.

Could it be some impurity flashing out of the paint?

It is mostly a problem on external walls, corners etc here. But... it doesn't really look like classic condensation/mould... One of our bathrooms really is a haven for condensation and the earthborn paint in there is fine.

In fact, we have no issues with any dark colour earthborn paint. But all of our white/yellow rooms need redecorating after just 2-3 years due to this blotching.

 

[a twig]

Definitely some quality / repeatability issues with Earthborn, when I’ve come back to touch up areas a year or two later and bought a new tin, you can definitely see the difference

 

[MatthewC]

Just for balance, I have used Earthborn paint in my hall/landing/stairs plus lounge and a couple of bedrooms, and there's been no problems at all. In most places it was done on lime plastered walls which were limewashed a few years earlier (but which just didn't look right for my other half). However, this lack of problems could be because my house is wonderfully dry due to the other work I did! 8)

 

[Sikes]

Thanks for all the replies. Seems a few people have similar problems. We did we have a difference in tone between pots of Earthborn. We are going to try a test pot of a different Earthborn color. Maybe one patch with only Earthborn and another with Zinsser Grade 1 underneath.

 

[a twig]

At £74 a tin for that Zinsser Grade 1 stuff I certainly wouldn’t bother putting anything over it

It’s supposed to be a “one paint system” that does it all while remaining breathable and it is tintable if you don’t want white.

Would defeat the point painting over it with something else

 

[TheSpid]

Interesting, we have this blotting but only on one wall, and it’s in Humpty Dumpty, old yellow gold colour. The wall I would expect to colour if it was mould is the opposite wall in Straw where we definitely still have a few issues with damp ingress round the windows but no splotching there. Most is mainly around two pictures at 4ft high, nothing lower. Could it be colour specific? Very odd. Has anyone contacted Earthborn?

 

[tobydog]

We have a cold wall in our cottage. When we moved here in 2009 it was evident that numerous attempts by a damp treatment company to sort the problem had failed. The warranty was about to expire but I simply let it lapse because it was obvious that they didn't know how to sort it.

Every winter heavy condensation would form on the acrylic based paint but, oddly, only on the precise area they had 'repaired' (about 12 square ft). I stripped off the paint (it actually almost fell off) down to the gypsum skim. Not wishing to strip the render (Limelite) I just left it to dry out for some time. I followed this with a coat of Earthborn clay paint and now no more condensation. Yes, the wall is still slightly colder than the others, but no wet wall and no problems with blotchy paint finish. I know the underlying problem isn't fixed and ultimately it will still come up when we sell.

 

[Sikes]

I'll continue to use Earthborn but can anybody recommend any other brands?

 

[noj]

Most is mainly around two pictures at 4ft high, nothing lower. Could it be colour specific? Very odd. Has anyone contacted Earthborn?

Similar here (vanilla, painted 6 years ago, so not too bad) spotting around/below pictures, but not behind them. It's a cold wall, but again not the areas where you'd expect condensation. The wall where there is a little damp it's flaked a little but no spotting...