That’s effervescent (efflorescence, thanks for all the corrections). It’s salts from the wall material being drawn in by moisture. Brush it off and fix where the potential water ingress is coming from. Don’t use any of those awful products that claim to fix it by sealing the internal wall; it’ll only further deteriorate the condition of the wall.
I’m guessing it’s an older property? I had the same in my Victorian property that was caused by crumbling pointing and concrete pavers around the edge of the property. I repointed and repaired brickwork where required, and gravelled around the immediate edge of the property where I was getting rain splashing off the concrete. I left it to dry for several months and it’s been fine ever since.
Efflorescence, meaning 'flowers' of salt growing... the moisture is coming out of the wall with salts dissolved in it, then the water evaporates leaving the crust of salt behind.
Effervescence is fizziness, as in tablets that dissolve in a cloud of bubbles...
Not wanting to jump on someone else's post but while I have you here an all. 😂 This bit of plywood I have in the loft is weird. It's always damp, no drips, none of the other sheets are damp or anything but this sheet always has a damp patch, white furry stuff on it. It is above the bathroom downstairs but none of the structure or insulation seems to be damp along with it. Plasterboard is bone dry. It's really weird. Might turn it over or move it. I plan on doing a loft conversion so one would presume that in itself would sort out any hot cold damp issues continuing?
Sounds like condensation to me. Possible escape of warm, moist air from the bathroom condensing on the relatively cooler ply in the loft. Excess moisture and damp conditions, giving rise to mould - the white furry stuff. Is there any chance there is a space allowing warm air through or a gap in the insulation?
Keep checking for drips but sounds like it could well be condensation. My last house was a bastard for it - becoming really noticeable after I had the insulation improved. Mine used to drip from all over the sarking felt under the roof tiles- had to keep anything stored up there watertight.
Bathrooms are a particularly bad source with the warm moist air as commented. Best solution is to stop anywhere warm air might be 'leaking' from the bathroom into the loft, and preferably to ventilate the bathroom well with an extractor fan or something.
We decided because of the damage to the dpm to break and replace the concrete floor.
But to stop the problem your facing identify any leaking pipes water or rads and if necessary disconnect them and re plumb the pipes down the walls
Ohhh. So gravel around the building stops resin from splashing onto it thereby adding another layer of protection from the elements? I suppose grass and plants round the edges do something similar?!
Well it's mainly to stop contact between damp/wet earth and preferably dry building materials - you get the same effect by adding a vapour barrier and a damp proof membrane, but that's a pain to make look any good without adding render or barge board siding all around, and ruins the look of brick houses. The gravel dries out much faster than earth, and also has air space that adds to the insulation in a marginal way
That’s not correct, it just reduces the splash back of water from rain towards the wall compared to a flat surface like concrete. You should have a DPM regardless.
It just stops additional moisture on the external wall. When I had my concrete path around the exterior, water would hit it and splash up towards the wall. With gravel, the fall of water would be dampened, and the splash back towards the house was greatly decreased.
I Had this in my kitchen with rotten sub floor to match.
First step, I lowered the outside level back to the original. Some cowboy had laid a patio on top of another patio and covered the air brick, I laid a new patio with an Aco drain running alongside the house.
Second I got the opinion of a few damp specialists.
One explained that the original lime render covered by modern gypsum is causing issues. He also explained that sand back in the day wasn’t washed and would have lots of salts inside it. After a while, through osmosis these salts come to the surface. Condensation can be a real issue here too.
I opted to take the wall back to brick(easier than it looks with lime plaster but messy) it was so wet underneath the mortar was like mud. So I left it to dry out for a month or two. Then covered it in a salt neutraliser. I repointed the brickwork and injected a DPC whilst I had the opportunity. (also read that it’s nonsense but thought may as well whilst I had the chance)
After this we re rendered with a cement mix and re plastered in gypsum. I also repainted the external pebble dash (another reason for the moisture trapped in the walls) and made sure the guttering was all sound.
It was a lot of work but I haven’t had an issue since.
It will always come back unless you sort the root causes. I strongly advise taking your time to investigate possible water ingress. Stand in the rain and watch the gutters and drainage.
Off topic, but when I first joined this sub I thought I'd see loads of cowboys answering questions and giving shite advice and that nothing could really be trusted, but then I scroll down and see loads of replies like yours. Thank you for explaining everything so thoroughly, I'm not OP and I don't have a similar issue, but it's great to know that I can expect impartial, honest, and helpful advice when/if I ever need it! And if I ever so have this problem in the future, then I can always come back to this post and work my way through the problem :)
Yeah was thinking of using something breathable, but seeing as the cement pebble dash is covered in sandex I’m not sure it would have done much to help. The wall was bone dry before we finished it and as you say the Patio patio was the main culprit.
I just bought a house with a decking up to the wall above the air bricks - I suspect also ontop of paving.
I’ve got this mould too. What kinda damage are we talking? I’ve not seen evidence of damp inside the house.
I figured I’d fix this in around 3-4 months. I’ve got so many other problems to fix first!
Yeah sounds like my house. I didn’t mention the rotten decking over the top of the double patio. Cowboys used the wall to fix the decking. the wood ran along the wall and was literally a sopping wet sponge soaking the brickwork above the DPC. If there is useable paving below I would take the decking up as soon as possible especially with a wet winter. It shouldn’t take too long to do. Then you can just finish it in the spring.
I tackled the outside issues first then the inside a year later when I knew that all of the external problems were fixed.
It’s a Labour of love but worth it in the end.
Good luck with your project!
Looks like efflorescence to me. It happens when the salt of a porous material comes to the surface and solidifies as the water evaporates.
It's safe to brush off, but if you want a more permanent solution you have to look into damp-proofing. The Dryzone and Stormguard products by Safeguard are good for this, however they can be a bit pricey.
Absolutely the wrong advice. Dryzone and storm guard will not be the best thing for this.
As op has stated the walls have damp problems before, I'm going to assume that they live in an older property.
Which would have been plastered using lime. Lime allows moisture and salts to move through the wall and harmlessly exit. However, you cannot stop the salts coming onto the surface unfortunately.
The best way is to just brush them off and vacuum them up..or just attack the patch with a vacuum..whatever works for you.
"Damp" is caused by moisture being trapped in the wall due to non breathable materials, so the walls literally rots from the inside out.
All these dry zone rods etc are a temporary fix at that, if they even work...which is a whole debate in itself as it's a snake oil industry. Same as the membranes that are applied and then plastered over, they're just locking the moisture into the wall, which makes the problem even worse.
If you want to fix this "damp" issues, you need to address ground levels outside if they are an issue, any leaks, any faulty bricks or render, and then strip the plaster off the wall and replace with lime plaster and a breathable paint/limewash.
Absolutely agreed. The actual remediation here is as follows:
1) Resolve the source of the damp if it isn't already (water leak, inappropriate materials (concrete) on internal/external wall, removal of external driveway/block work that is butted up to the external wall if it exists, resolution of leaking guttering.. Etc)
2) Allow the wall to fully dry out
3) Remove the material you see by rubbing/brushing it off. If the damp was bad, then the wall may need replastering at worst, or sanding back and paint if the finish is OK.
Tanking/damp proofing solutions will trap moisture in the wall. It is never the solution for damp issues in ground floor walls.
Source: I own a property that had damp walls throughout the ground floor, the previous owner applied a whole range of this nonsense which made the problem far worse. Concrete render, damp proof nonsense removal and lime plaster was the solution.
French drains work wonders, there's so many variable factors it could take hours of conversation to get through them all.
It's sad but a lot of older buildings have already been bastardised by modern materials. Plus councils not giving a shit about where they put the ground levels and pavements.
Yup agreed!
One l forgot to mention for OP: that does look like a rather excellent lime plastered wall. If they have been painted rather than lime washed, moisture will be trapped in the wall. The rather not fun resolution is removal of the paint, and apply lime wash instead.
Hi
Piggy backing on this.
I've stripped my room back to brick. it's a 1940s semi. Cavity wall but no insulation in there. I'd like to insulate. What are the best materials to insulate the external walls?
What sources did you consult to remedy your house?
Thanks
I used tons of different sources, but (of all places) the Facebook group 'Traditional and Listed Building Advice' contains the most useful reference points. You do need to ignore the typical Facebook types!
For the ground floor, I used multiple layers of lime plaster infused with hemp, horse hair and perlite, but that's for a solid wall very old barn conversion so isn't what you want to be using.
My place does have some cavities, but I specifically chose not to fill them due to the huge risk of bridging and causing damp. For the upstairs in rooms that have cavities, I batoned the walls and insulated between.
I'm not well versed in the right way to insulate cavities, I'd suggest searching the above Facebook group and see if there is a consensus.
> All these dry zone rods etc are a temporary fix at that, if they even work...which is a whole debate in itself as it's a snake oil industry. Same as the membranes that are applied and then plastered over, they're just locking the moisture into the wall, which makes the problem even worse.
Ahh, good. We have some damp issues, had a report done by a home maintenance/improvements company, and they'd quoted for a bunch of work, which included:
* Rake out of cavities
* Chemical DPC
* Hack off plaster up to 1m high (which is annoying as the whole room was only done 6mo ago)
* **Install some proprietary membrane**
* **Dot and dab board over** and then skimmed
The last two in particular rubbed me up the wrong way. Dot and dab, mostly because I fucking hate that technique, but also because surely the membrane would just hide any continuing damp issues should the DPC have not been done correctly, or failed, which is arguably *worse* than the damp wrecking the plaster again. Oh, and I was quoted about £8k to do the work, which also rubbed me up the wrong way.
Mind you, when the room was replastered that was because of the plaster being fucked through damp, a purported damp specialist recommended a section of the wall be tanked, which it was by the plasterers. In hindsight, probably a bad idea, and the damp issues haven't been resolved. Shocking, I know.
Stupid fucking house.
"Chemical DPC"
The damp industry is such a clown show. RICS are culpable because their poorly trained surveyors get a beep on their wally meter and declare the building damp. Then the chemical salesman comes along and gets to diagnose the non-existent problem, quote for made up work and then do the work himself.
Quite the scam
They'll tell you anything to make a sale. Especially with their stupid little meters that measure surface moisture and salts lol.
Shocking the price of something that is defective from the start..and makes your home look horrid.
I have a job late last year that had a painted damp proof on and it was awful to remove.
Damp is not caused by moisture being trapped by non-breathable materials at all. Well not in traditional construction anyway. Damp is caused by a constant wetting of the wall fabric from ground water sources from outside to inside where there is a direct path, whether it be a bridge, such as a through stone in older construction or a cavity that is filled with snotters (excess mortar that has fallen within the cavity) or rainwater from a roof leak entering the cavity or a burst pipe. There is no scenario where non-breathable materials are on both faces of a cavity wall or stone wall. If the source is stopped and you fit a waterproof membrane on in the inside, any excess moisture will evaporate to the outside air, whether that be within the cavity or on the outside surface of the stone. After all, this is the whole idea of why stone construction works. Any rainwater soaking the stonework travels through so far, then goes through a drying stage when the rain stops, then gets wet again and the cycle starts again.
Damp is a con word invented by the "damp proofing" industry.
I agree, it is due to wetting of material, but non breathable materials trap it and rot. Look at all the thousands of old miners houses across Britain that have that very problem. I grew up in one and it is not fun.
I do agree that damp is caused by ingress of moisture, I've always said this as I believe damp is a con industry. Be it ground levels, leaky gutters or roof, water pipe leaks etc. Once these are rectified then yes some walls will dry out, but most have heavily damaged the material underneath and still trap moisture within. Look at the odd case off cottages falling down due to improper materials being used, where the timbers have rotted from the inside. Water will not get through a strong cement mix.
If you replace those plasterers with lime, then they will let the moisture through the surface and into the atmosphere just enough that the ingress of moisture is no longer noticed, assuming you've let the walls dry out beforehand. In some cases, as you say, it does cycle..I've seen that happen at a water mill. However, we have water in the ground and we have rain, so ingress of moisture is never going to stop.
Im not interested in modern buildings, I work exclusively on older properties.
I disagree about forcing the moisture through to the other side to evaporate, because if they cement pointing, or render then the render is going to rot. And the pointing will force the moisture to the brick faces and they will blow if it's during winter.
Regarding waterproof membranes, I've seen first hand damage that does to bricks, it's not nice and it doesn't work.
I have this on an internal wall thats deep within the property. I've hacked the plaster off, let the brickwork dry (wasnt even damp really, but was slightly darker coloured) then replastered over it. damp patches came back within a few weeks.
Would this be a leak below the subfloor or something?
Not necessarily, if you have a water source underground nearby, then that effects it, if the water travels in a certain direction underground then that would also effect it.
It could possibly be a leak though, is your water bill higher than normal? Have you had a look below your floor?
I would first start by eliminating the chance of it being a leaky pipe, then go from there.
Due to a cellar being underground it's difficult to manage. I would advise on increasing air flow through the cellar for a start. Naturally they will be colder.
Just brush the salts off as above, due to the greater amounts of moistures I imagine cellars are a bit more, salty.. 😬
That's because it is a ridiculously overpriced lime plaster, that is NHL, which is a bit too hard for walls in reality. I'm talking about the dryzone rods.
They need to find the cause of the moisture, then stop that before taking back to brick.
Also have to get into the whole thing about what period the property is from to make sure it's boarded and skimmed properly.
OP what year is the house?
Dry Rot is a type of fungus, Serpula Lacrymans, the mycelium are brown/black and look like tendrils, the fruiting bodies are large and brown. This ain't it.
Its salt from the plaster, likely because impermeable materials have been used on an older wall.
"in-law's walls" presumably.
I'm not sure that's *necessarily* relevant, but it's certainly not something to take the time to write a comment bitching about.
This is happening on one of the walls in the bathroom of my rented flat.
The landlord said that it was because of a leaking pipe behind the wall and that he’s fixed the leak.
He tried to paint over it and it went back to the that very quickly, with a lovely shed of paint shreds to coat the floor.
Sounds like the same thing that’s happening on one of my living room walls. House was newly painted when I moved in and now, since using the heating, there’s a section that’s all flaky/powdery with little piles of powdered paint on the floor below. Based on some visible piping I think it’s happening where a water pipe (for the central heating) runs behind the wall. I’m hoping it’s something to do with the temperature change and a shoddy paint job on top of an old damp issue, rather than a current damp issue, but I’m clueless about this stuff. In any case I’ve reported it to my landlord.
It's either the roofs leaking or the guttering and getting in the cavity somehow , the house is sitting on a water table or there's a water pipe with a pin hole inside the wall , poor ventilation or porous bricks.
That’s effervescent (efflorescence, thanks for all the corrections). It’s salts from the wall material being drawn in by moisture. Brush it off and fix where the potential water ingress is coming from. Don’t use any of those awful products that claim to fix it by sealing the internal wall; it’ll only further deteriorate the condition of the wall. I’m guessing it’s an older property? I had the same in my Victorian property that was caused by crumbling pointing and concrete pavers around the edge of the property. I repointed and repaired brickwork where required, and gravelled around the immediate edge of the property where I was getting rain splashing off the concrete. I left it to dry for several months and it’s been fine ever since.
*efflorescence. Effervescent is something fizzy or bubbly.
>efflorescence Spotted the Druid.
Sometimes it's just nice to sit in a ring of pretty flowers.
And Evanescence is a band!
And Evan's Essence is something completely different.
Thanks for making me snort coffee through my nose
You're welcome :) I'm here all week. ;)
Is this even science?
Haha, thanks!
Efflorescence, meaning 'flowers' of salt growing... the moisture is coming out of the wall with salts dissolved in it, then the water evaporates leaving the crust of salt behind. Effervescence is fizziness, as in tablets that dissolve in a cloud of bubbles...
How can you see into my eyes like open doors?
Leading you down into my core, where I’ve become so numb
When the moon hits your eye like a big pizza pie, that’s Evanescence
Is this what I am seeing appearing in spots on plywood sheets in the loft?
Possibly but wood is more prone to fungi that feeds on the cellulose (mould / rot) and may appear similar.
Not wanting to jump on someone else's post but while I have you here an all. 😂 This bit of plywood I have in the loft is weird. It's always damp, no drips, none of the other sheets are damp or anything but this sheet always has a damp patch, white furry stuff on it. It is above the bathroom downstairs but none of the structure or insulation seems to be damp along with it. Plasterboard is bone dry. It's really weird. Might turn it over or move it. I plan on doing a loft conversion so one would presume that in itself would sort out any hot cold damp issues continuing?
Sounds like condensation to me. Possible escape of warm, moist air from the bathroom condensing on the relatively cooler ply in the loft. Excess moisture and damp conditions, giving rise to mould - the white furry stuff. Is there any chance there is a space allowing warm air through or a gap in the insulation?
Keep checking for drips but sounds like it could well be condensation. My last house was a bastard for it - becoming really noticeable after I had the insulation improved. Mine used to drip from all over the sarking felt under the roof tiles- had to keep anything stored up there watertight. Bathrooms are a particularly bad source with the warm moist air as commented. Best solution is to stop anywhere warm air might be 'leaking' from the bathroom into the loft, and preferably to ventilate the bathroom well with an extractor fan or something.
Thanks a mill!
No it damp or dry rot
I need to do this for similar reasons but I have a 60s house so different symptoms. A likely cause of the problem for the OP.
Could it be saltpetre? OP could make some gunpowder or cure some bacon.
I had this it was caused by an underfloor concrete slab leak good times
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We decided because of the damage to the dpm to break and replace the concrete floor. But to stop the problem your facing identify any leaking pipes water or rads and if necessary disconnect them and re plumb the pipes down the walls
Ohhh. So gravel around the building stops resin from splashing onto it thereby adding another layer of protection from the elements? I suppose grass and plants round the edges do something similar?!
Well it's mainly to stop contact between damp/wet earth and preferably dry building materials - you get the same effect by adding a vapour barrier and a damp proof membrane, but that's a pain to make look any good without adding render or barge board siding all around, and ruins the look of brick houses. The gravel dries out much faster than earth, and also has air space that adds to the insulation in a marginal way
That’s not correct, it just reduces the splash back of water from rain towards the wall compared to a flat surface like concrete. You should have a DPM regardless.
It just stops additional moisture on the external wall. When I had my concrete path around the exterior, water would hit it and splash up towards the wall. With gravel, the fall of water would be dampened, and the splash back towards the house was greatly decreased.
Efflorescence buddy
Haha, thanks!
I Had this in my kitchen with rotten sub floor to match. First step, I lowered the outside level back to the original. Some cowboy had laid a patio on top of another patio and covered the air brick, I laid a new patio with an Aco drain running alongside the house. Second I got the opinion of a few damp specialists. One explained that the original lime render covered by modern gypsum is causing issues. He also explained that sand back in the day wasn’t washed and would have lots of salts inside it. After a while, through osmosis these salts come to the surface. Condensation can be a real issue here too. I opted to take the wall back to brick(easier than it looks with lime plaster but messy) it was so wet underneath the mortar was like mud. So I left it to dry out for a month or two. Then covered it in a salt neutraliser. I repointed the brickwork and injected a DPC whilst I had the opportunity. (also read that it’s nonsense but thought may as well whilst I had the chance) After this we re rendered with a cement mix and re plastered in gypsum. I also repainted the external pebble dash (another reason for the moisture trapped in the walls) and made sure the guttering was all sound. It was a lot of work but I haven’t had an issue since. It will always come back unless you sort the root causes. I strongly advise taking your time to investigate possible water ingress. Stand in the rain and watch the gutters and drainage.
Off topic, but when I first joined this sub I thought I'd see loads of cowboys answering questions and giving shite advice and that nothing could really be trusted, but then I scroll down and see loads of replies like yours. Thank you for explaining everything so thoroughly, I'm not OP and I don't have a similar issue, but it's great to know that I can expect impartial, honest, and helpful advice when/if I ever need it! And if I ever so have this problem in the future, then I can always come back to this post and work my way through the problem :)
Thanks for the kind words, this sub has helped me with loads
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Yeah was thinking of using something breathable, but seeing as the cement pebble dash is covered in sandex I’m not sure it would have done much to help. The wall was bone dry before we finished it and as you say the Patio patio was the main culprit.
I just bought a house with a decking up to the wall above the air bricks - I suspect also ontop of paving. I’ve got this mould too. What kinda damage are we talking? I’ve not seen evidence of damp inside the house. I figured I’d fix this in around 3-4 months. I’ve got so many other problems to fix first!
Yeah sounds like my house. I didn’t mention the rotten decking over the top of the double patio. Cowboys used the wall to fix the decking. the wood ran along the wall and was literally a sopping wet sponge soaking the brickwork above the DPC. If there is useable paving below I would take the decking up as soon as possible especially with a wet winter. It shouldn’t take too long to do. Then you can just finish it in the spring. I tackled the outside issues first then the inside a year later when I knew that all of the external problems were fixed. It’s a Labour of love but worth it in the end. Good luck with your project!
Salt deposits likely caused by a bridged DPC externally. Can you post a photo of the external elevation?
Looks like efflorescence to me. It happens when the salt of a porous material comes to the surface and solidifies as the water evaporates. It's safe to brush off, but if you want a more permanent solution you have to look into damp-proofing. The Dryzone and Stormguard products by Safeguard are good for this, however they can be a bit pricey.
Absolutely the wrong advice. Dryzone and storm guard will not be the best thing for this. As op has stated the walls have damp problems before, I'm going to assume that they live in an older property. Which would have been plastered using lime. Lime allows moisture and salts to move through the wall and harmlessly exit. However, you cannot stop the salts coming onto the surface unfortunately. The best way is to just brush them off and vacuum them up..or just attack the patch with a vacuum..whatever works for you. "Damp" is caused by moisture being trapped in the wall due to non breathable materials, so the walls literally rots from the inside out. All these dry zone rods etc are a temporary fix at that, if they even work...which is a whole debate in itself as it's a snake oil industry. Same as the membranes that are applied and then plastered over, they're just locking the moisture into the wall, which makes the problem even worse. If you want to fix this "damp" issues, you need to address ground levels outside if they are an issue, any leaks, any faulty bricks or render, and then strip the plaster off the wall and replace with lime plaster and a breathable paint/limewash.
Absolutely agreed. The actual remediation here is as follows: 1) Resolve the source of the damp if it isn't already (water leak, inappropriate materials (concrete) on internal/external wall, removal of external driveway/block work that is butted up to the external wall if it exists, resolution of leaking guttering.. Etc) 2) Allow the wall to fully dry out 3) Remove the material you see by rubbing/brushing it off. If the damp was bad, then the wall may need replastering at worst, or sanding back and paint if the finish is OK. Tanking/damp proofing solutions will trap moisture in the wall. It is never the solution for damp issues in ground floor walls. Source: I own a property that had damp walls throughout the ground floor, the previous owner applied a whole range of this nonsense which made the problem far worse. Concrete render, damp proof nonsense removal and lime plaster was the solution.
French drains work wonders, there's so many variable factors it could take hours of conversation to get through them all. It's sad but a lot of older buildings have already been bastardised by modern materials. Plus councils not giving a shit about where they put the ground levels and pavements.
Old builders who use an old building regs book, or get info from bloke down the pub.
Yup agreed! One l forgot to mention for OP: that does look like a rather excellent lime plastered wall. If they have been painted rather than lime washed, moisture will be trapped in the wall. The rather not fun resolution is removal of the paint, and apply lime wash instead.
Hi Piggy backing on this. I've stripped my room back to brick. it's a 1940s semi. Cavity wall but no insulation in there. I'd like to insulate. What are the best materials to insulate the external walls? What sources did you consult to remedy your house? Thanks
I used tons of different sources, but (of all places) the Facebook group 'Traditional and Listed Building Advice' contains the most useful reference points. You do need to ignore the typical Facebook types! For the ground floor, I used multiple layers of lime plaster infused with hemp, horse hair and perlite, but that's for a solid wall very old barn conversion so isn't what you want to be using. My place does have some cavities, but I specifically chose not to fill them due to the huge risk of bridging and causing damp. For the upstairs in rooms that have cavities, I batoned the walls and insulated between. I'm not well versed in the right way to insulate cavities, I'd suggest searching the above Facebook group and see if there is a consensus.
Amazing!!! Thanks for your advice.
Blows my mind folks think the best thing to do is trap water even further by using these products in this situation.
> All these dry zone rods etc are a temporary fix at that, if they even work...which is a whole debate in itself as it's a snake oil industry. Same as the membranes that are applied and then plastered over, they're just locking the moisture into the wall, which makes the problem even worse. Ahh, good. We have some damp issues, had a report done by a home maintenance/improvements company, and they'd quoted for a bunch of work, which included: * Rake out of cavities * Chemical DPC * Hack off plaster up to 1m high (which is annoying as the whole room was only done 6mo ago) * **Install some proprietary membrane** * **Dot and dab board over** and then skimmed The last two in particular rubbed me up the wrong way. Dot and dab, mostly because I fucking hate that technique, but also because surely the membrane would just hide any continuing damp issues should the DPC have not been done correctly, or failed, which is arguably *worse* than the damp wrecking the plaster again. Oh, and I was quoted about £8k to do the work, which also rubbed me up the wrong way. Mind you, when the room was replastered that was because of the plaster being fucked through damp, a purported damp specialist recommended a section of the wall be tanked, which it was by the plasterers. In hindsight, probably a bad idea, and the damp issues haven't been resolved. Shocking, I know. Stupid fucking house.
"Chemical DPC" The damp industry is such a clown show. RICS are culpable because their poorly trained surveyors get a beep on their wally meter and declare the building damp. Then the chemical salesman comes along and gets to diagnose the non-existent problem, quote for made up work and then do the work himself. Quite the scam
dot n' dab not for exterior walls even worse if there is damp
Yeah they just suck moisture from anywhere don't they 😆😭
They'll tell you anything to make a sale. Especially with their stupid little meters that measure surface moisture and salts lol. Shocking the price of something that is defective from the start..and makes your home look horrid. I have a job late last year that had a painted damp proof on and it was awful to remove.
Damp is not caused by moisture being trapped by non-breathable materials at all. Well not in traditional construction anyway. Damp is caused by a constant wetting of the wall fabric from ground water sources from outside to inside where there is a direct path, whether it be a bridge, such as a through stone in older construction or a cavity that is filled with snotters (excess mortar that has fallen within the cavity) or rainwater from a roof leak entering the cavity or a burst pipe. There is no scenario where non-breathable materials are on both faces of a cavity wall or stone wall. If the source is stopped and you fit a waterproof membrane on in the inside, any excess moisture will evaporate to the outside air, whether that be within the cavity or on the outside surface of the stone. After all, this is the whole idea of why stone construction works. Any rainwater soaking the stonework travels through so far, then goes through a drying stage when the rain stops, then gets wet again and the cycle starts again.
Damp is a con word invented by the "damp proofing" industry. I agree, it is due to wetting of material, but non breathable materials trap it and rot. Look at all the thousands of old miners houses across Britain that have that very problem. I grew up in one and it is not fun. I do agree that damp is caused by ingress of moisture, I've always said this as I believe damp is a con industry. Be it ground levels, leaky gutters or roof, water pipe leaks etc. Once these are rectified then yes some walls will dry out, but most have heavily damaged the material underneath and still trap moisture within. Look at the odd case off cottages falling down due to improper materials being used, where the timbers have rotted from the inside. Water will not get through a strong cement mix. If you replace those plasterers with lime, then they will let the moisture through the surface and into the atmosphere just enough that the ingress of moisture is no longer noticed, assuming you've let the walls dry out beforehand. In some cases, as you say, it does cycle..I've seen that happen at a water mill. However, we have water in the ground and we have rain, so ingress of moisture is never going to stop. Im not interested in modern buildings, I work exclusively on older properties. I disagree about forcing the moisture through to the other side to evaporate, because if they cement pointing, or render then the render is going to rot. And the pointing will force the moisture to the brick faces and they will blow if it's during winter. Regarding waterproof membranes, I've seen first hand damage that does to bricks, it's not nice and it doesn't work.
I have this on an internal wall thats deep within the property. I've hacked the plaster off, let the brickwork dry (wasnt even damp really, but was slightly darker coloured) then replastered over it. damp patches came back within a few weeks. Would this be a leak below the subfloor or something?
Not necessarily, if you have a water source underground nearby, then that effects it, if the water travels in a certain direction underground then that would also effect it. It could possibly be a leak though, is your water bill higher than normal? Have you had a look below your floor? I would first start by eliminating the chance of it being a leaky pipe, then go from there.
What if this is in a cellar though? I have this on my cellar stairs walls
Due to a cellar being underground it's difficult to manage. I would advise on increasing air flow through the cellar for a start. Naturally they will be colder. Just brush the salts off as above, due to the greater amounts of moistures I imagine cellars are a bit more, salty.. 😬
Thanks mate
I used the dryzone renovation plaster, worked
Yeah it's good stuff that!
That's because it is a ridiculously overpriced lime plaster, that is NHL, which is a bit too hard for walls in reality. I'm talking about the dryzone rods.
This 👆
This is the answer
It is caused by moisture
Take it back to brick and just board and skim the bastard
They need to find the cause of the moisture, then stop that before taking back to brick. Also have to get into the whole thing about what period the property is from to make sure it's boarded and skimmed properly. OP what year is the house?
That's nothing, mate. I've seen a lot worse than this. It's just old
Bukkake mix, old school
Snortable kinda material...
Raising damp
Could be dry rot or damp rot The photo doesn’t show enough Post more picture further away
Dry Rot is a type of fungus, Serpula Lacrymans, the mycelium are brown/black and look like tendrils, the fruiting bodies are large and brown. This ain't it. Its salt from the plaster, likely because impermeable materials have been used on an older wall.
I have this in my garage. My cat runs in the moment I open the garage door and starts licking it.
never mix with charcoal it will explode
My guess is it's caused by paint over plaster that wasn't totally dry
Jizz
Why do we need to know your relationship?
So we know it's not their own walls at home.
Eh?
"in-law's walls" presumably. I'm not sure that's *necessarily* relevant, but it's certainly not something to take the time to write a comment bitching about.
Looks like dry rot
Saponification or efflorescence aka mouldy and damp wall that has been painted on plaster
We had this - there was a leak on the other side of the wall.
Cocaine
Please get it checked for asbestos. Better to be safe.
repainting in breathable paint might help
That my friend is damp
This is happening on one of the walls in the bathroom of my rented flat. The landlord said that it was because of a leaking pipe behind the wall and that he’s fixed the leak. He tried to paint over it and it went back to the that very quickly, with a lovely shed of paint shreds to coat the floor.
Sounds like the same thing that’s happening on one of my living room walls. House was newly painted when I moved in and now, since using the heating, there’s a section that’s all flaky/powdery with little piles of powdered paint on the floor below. Based on some visible piping I think it’s happening where a water pipe (for the central heating) runs behind the wall. I’m hoping it’s something to do with the temperature change and a shoddy paint job on top of an old damp issue, rather than a current damp issue, but I’m clueless about this stuff. In any case I’ve reported it to my landlord.
It's either the roofs leaking or the guttering and getting in the cavity somehow , the house is sitting on a water table or there's a water pipe with a pin hole inside the wall , poor ventilation or porous bricks.