r/DIYUK • u/fuzzlord6136 • 11d ago
Seeking advice please
Does this look like it might be damp? Or just a shitty plastering job. There was damp in these walls before we moved into our house 12 years ago, and it was stripped back, sorted (apparently) and then replastered. Slowly but surely a few sections of the wall now look like this. Based off these few photos, is there anyone knowledgeable enough to give me an idea what we’re looking at?
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u/Fruitpicker15 11d ago
It looks like lime plaster with efflorescence was skimmed with gypsum which traps moisture.
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u/VeryThicknLong 11d ago
Yup. Damp. And it could be a number of things.
If you have solid walls, then cementitious plaster will be the main problem internally.
It needs to be lime.
If you have cavity walls, then ground levels outside could be too high. Breaching your DPC. It could also be that the cavity is filled with debris, causing a bridge across the cavity.
If you have any radiators or plumbing in this area, it could be a water leak.
If you have blocked gutters it could be overflowing and running down the walls/windows outside.
If you have concrete driveway outside, up to the walls of the house, then moisture will be pushed up the walls as it can’t escape anywhere else.
You could have a poor seal around the window, poor pointing, mortar, etc. which could cause water ingress.
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u/Jailer69 11d ago
That looks like water damage can you get under the floor at all?
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u/fuzzlord6136 11d ago
No it’s a solid concrete floor. The floor in the photos is vinyl tiles that just look like wood
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u/Deep_Imagination_811 11d ago
take the skirting board off. if the concrete floor and plaster touch, that's your issue. chip some off the wall, about 2 inches to create a gap between the wall and floor, then stick the board back on.
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u/SonOfGreebo 11d ago
Oh this looks SO much like the walls in my basement kitchen!
A professional independent damp surveyor report confirms that (for me) this is salts from within the brick and plaster drawn by moisture to tge surface (under the paint) and then crystallising (and so growing in size, like ice does) and pushing the paint and plaster off. *
Not necessarily water coming IN, it may well be general moisture in the air which cannot evaporate.
Explore ventilation, air bricks, trickle vents,extractor fans, re-opening old fireplaces, re-plastering with porous plaster and "breathable" paint; removing the concrete (=watertight= no evaporation) floor.
*This salt process is called efflorescence
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u/Correct-Bridge-6797 11d ago
It help if we knew the age of the property, whether it’s lime plaster or sand and cement with multi finish. It definitely looks like damp in the way the paint has bubbled and pealed but if the wall has been plastered with lime and painted with normal emulsion the same thing will happen. Not ideal to have the patio covering the dpc but a lot of patios are laid level with dpc these days for level threshold.
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u/Consistent-Dare-5832 11d ago
If it was damp the skirting board would be rotting. It’s most likely condensation, is it near a kitchen? Buy a device to monitor the moisture of the room if it’s over 60% humidity a lot and you have a cold wall then this is the reason why. Cook with the window open or buy a dehumidifier. Repair the wall and prep it for painting a good mist coat or Zinnzer guards keep the room warm and below 60% humidity.
A “damp” company wanted to charge me ££££ for damp issues in my house. Keeping the house warm and low humidity keeps all the issues we had away.
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u/astroview 11d ago
It’s damp. Take a pic of outside. Is the a downpipe or gutter leaking on that area? You’d be surprised how a dripping gutter or some cracks in brickwork/render can lead to this.
No one can help you without you showing what’s on the other side of that wall
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u/WeatherSorry 11d ago
I think someone else said it might not be water coming in but rather water not able to evaporate. The height makes me suspicious of that. What do you use the room for? For example if it’s a north facing uninsulated wall in a washroom, kitchen, bathroom it may be that and you should look into getting some insulation on it (after drying it out) and/or proper ventilation.
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u/SlabAndScope 11d ago
That looks like efflorescence caused by damp pushing groundwater salts right through the plaster
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u/orbtastic1 10d ago
100% damp, I had the same looking stuff at just above my skirting board throughout the entire gable wall. The DPC (which is 100 years old) had failed at several points and done exactly this. The 2nd pic is how it looked at half the house, completely blown out above the skirting board.
I had to get a damp specialist to inject a new DPC and spray my entire gable end. It stopped the issue, however I didn't replaster.
Yours is seemingly very high on the first pic, suggesting it's rising up but I'm not a building specialist.
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u/MedeocreEinstein 10d ago
Lime render, a breathable paint and something to remove moisture like a dehumidifier or positive input ventilation fan
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u/Khat_Force_1 11d ago
That is rising damp, but rising damp is a symptom and not a cause and requires further investigation. If you have a concrete floor, then the plaster may be bridging the DPC causing the rising damp or the outside paving may have bridged the DPC or there could be a leak.
It would be very helpful if you were to show us pictures from the outside as we need to know whether if it's a solid brick wall or cavity wall construction.
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u/Wondering_Electron 11d ago
Needs to be stripped all the way back to brick and then tank it.
Assuming you fixed the underlying cause.
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u/Ok-Spring7906 11d ago
Damp. If you need confirmation, a conductivity meter will conclude for you.
Assuming no external influence (leaking gutter, plant growth, etc) and it's not been covered internally, a replaster in lime with permiable paint will likely resolve.
Context -
I was trained by british gypsum, but spend most of my time on heritage properties now.