Well, I've seen damp walls and found leaking pipes in the vicinity, fixing of which has resulted in the wall drying out; thus, moisture from said leak had risen up the wall and made it damp, if not soaked.Is this something that you've seen happen?
If so, perhaps it should be called Rising Drench.
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I've seen this happen lots of times and had a case only last week. Damp profile appeared exactly as you would expect for rising damp, i.e, higher readings at wall base which diminished with height. I didn't even test for rising damp, I carried out a simple back syphon test on the water mains and found there was a leak under the floor of the lounge. This is a useful test... Isolate the main stopcock outside the property, fill a glass with water and stick it under the tap. When you open up the tap, if the incoming main is leaking it will suck water from the glass by syphonic action.
Aye, so would this not be "rising damp"? Don't get me wrong, I am at one with the condemnation of misdiagnosis by surveyors with their meters and the self-interest of damp injection companies, as well as hating chemical injection, but if that's not rising something, what is it?
Personally, I would be prepared to call that Rising Damp.
However, before doing it I'd want to know whether or not the moisture path was through the brickwork, which has always been the widely misunderstood nub of my crusade against wrongly diagnosed, and wrongly treated, RD.
It isn't enough to know whether or not damp is rising - you have to know how it's rising to be able to stop it.
For example, I've seen countless examples of external render touching wet ground or concrete, bridging the nominal DPC on a solid wall, getting wet, blowing off in a frost, leaving a capillary path for water, said water then rising to above internal floor level and penetrating the wall.
You can pump as much silicone as you like into that wall and it won't stop the problem, even if it stops it temporarily, because as soon as a new section of render blows off the process will start all over again.
However, before doing it I'd want to know whether or not the moisture path was through the brickwork, which has always been the widely misunderstood nub of my crusade against wrongly diagnosed, and wrongly treated, RD.
It isn't enough to know whether or not damp is rising - you have to know how it's rising to be able to stop it.
For example, I've seen countless examples of external render touching wet ground or concrete, bridging the nominal DPC on a solid wall, getting wet, blowing off in a frost, leaving a capillary path for water, said water then rising to above internal floor level and penetrating the wall.
You can pump as much silicone as you like into that wall and it won't stop the problem, even if it stops it temporarily, because as soon as a new section of render blows off the process will start all over again.
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As I said, I'd simply describe it as wall base damp, the fact that it still rises up the wall isn't really important. The remedies for the wall base damp described and rising damp would be entirely different, this is what's important. The problem with these scenarios is that standard remedial works for rising damp (dpc injection and replastering) might appear to be equally successful for wall base damp. Purely because the waterproof renders used would dam in the damp and effectively give you a dry wall finish.
Ok, similar scenario. A defective gully on the outside of a solid wall, leading to copious quantities of water leaking into soil. Water soaks into wall, no dpc ever installed, low level damp internally. RD or PD, or both?
I think I'm understanding from you, Soft, that where the surveyor merely uses his DM and gets "high" surface readings, without checking the core of the wall in question and determines from his results that that is RD, rather than due to moisture take up from the internal environment, is what gets your goat? If so, am with you 100% on that.
I think I'm understanding from you, Soft, that where the surveyor merely uses his DM and gets "high" surface readings, without checking the core of the wall in question and determines from his results that that is RD, rather than due to moisture take up from the internal environment, is what gets your goat? If so, am with you 100% on that.
Shy, you've answered your own question. It doesn't matter where the water in the soil comes from, if it's leached up the walls from below dpc level then it's rising damp and by virtue of the fact that its leached into the soil will contain nitrates. One of the greatest contributory factors for rising damp is a high water table and quite often you can resolve rising damp at source by lowering the water table. It's a proven fact that theres a direct relationship between the height of the water table and the height damp can rise to in a wall.
I should also clarify the issue relating to properties without a physical dpc present. In these cases external ground levels should be 200mm below internal finished floor level. If the damp is caused by high external ground levels then technically this is still a 'bridging' issue because you're bridging the free area required for wall base ventilation. These cases are the exception to the rule, technically still rising damp but I prefer to categorise them as cases of penetrating damp purely because I like to categorise in relation to the remedy that's required. If the free area required at the wall base was present then I'd term it rising damp.
Incidently I've posted a photo in my album, clear evidence that rising damp does exist. //www.diynot.com/network/joe malone/albums/
Ok guys,
lets say that Rd does exist as a fair hypothesis, and that it is rare, but not unknown, (leaving aside the possibility of leaking pipes, as, if the leak is stopped then the problem is presumably solved).
However condensation in modern(ised) houses does exsist, and I would say in most, due to the lack of unplanned ventilation, (drafts)
When I were a lad.... we only had single glazed windows, which had beautiful ice crystals on them inside every cold winters morning, (and that means Nov to April).
So, every human exhales about 2 litres of liquid in their breath every 24 hours, where does all that water go?
It 'finds' the coldest area in the house, typically behind a wardrobe on an external wall, but also can be any cold corner in any room ,also kitchens bathrooms etc.
Think about it....
lets say that Rd does exist as a fair hypothesis, and that it is rare, but not unknown, (leaving aside the possibility of leaking pipes, as, if the leak is stopped then the problem is presumably solved).
However condensation in modern(ised) houses does exsist, and I would say in most, due to the lack of unplanned ventilation, (drafts)
When I were a lad.... we only had single glazed windows, which had beautiful ice crystals on them inside every cold winters morning, (and that means Nov to April).
So, every human exhales about 2 litres of liquid in their breath every 24 hours, where does all that water go?
It 'finds' the coldest area in the house, typically behind a wardrobe on an external wall, but also can be any cold corner in any room ,also kitchens bathrooms etc.
Think about it....
Nothing to think about, I manage the maintenance of 10,000 properties and can tell you that by far, the most common cause of damp is condensation. No one is stating otherwise but arguing that rising damp doesn't exist is like arguing that the world is flat. We have lots and lots of scientific data to prove that it does exist. There's an almost extremist approach here maybe as a backlash to a dpc industry that promotes rising damp as a common occurrence but two wrongs don't make a right.
Jeff Howell has a lot to answer for!
Jeff Howell has a lot to answer for!
Hi, Joe,
We seem to agree on the basics, but there is always 'something to think about', otherwise there could be no discussions about these matters.
I was a bricky for 23 years, and don't profess to be a damp expert, but your comments seem to me to be a fair assesment of the damp proof industry.
On a free forum like this there are bound to be helpful people and some less so, let all have there say and correct them (where necessary) with logic and facts.
Best regards chessspy.
We seem to agree on the basics, but there is always 'something to think about', otherwise there could be no discussions about these matters.
I was a bricky for 23 years, and don't profess to be a damp expert, but your comments seem to me to be a fair assesment of the damp proof industry.
On a free forum like this there are bound to be helpful people and some less so, let all have there say and correct them (where necessary) with logic and facts.
Best regards chessspy.
Chessspy, we almost certainly agree on the basics, without wanting to sound patronising; it's good to know that contributors can be self aware enough to question and challenge their initial perceptions.
Regards
Joe
Regards
Joe
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