Rising damp does not exist

[masona]

Softus, an interesting point from Jeff Howell Sunday Telegraph columnist here

My sister a few years ago had been told they have rising damp by the so called expert but couldn't afford to have it done, so I chopped the 1m high plaster and approx 3m wide, it was very slightly damp, so left it for a month, it's now bone dry, so if it was rising damp, why isn't it contining to be damp? My theory is my sister has the TV against the wall and some furniture causing what is known as "condensation pocket trap"

I believe there's a temperature differ in house rooms, with hotter air rising up to the top and colder air below and this is why you see condensation ocurring. If the walls is wet below the floor, the evaporation cooled down so water causes more thermal conduction thus lower the temperature above the floor

We proved it by moving the TV and furnitures to the other side of the room and not had any problem since.

BTW interesting topic.

 

[PatrickD]

This link shows a picture, taken this week, of a dwarf wall beneath the floor of a 1970's house.

Although the photo isn't brilliant and relies exclusively on flash for its lighting, the difference in colouration between the bricks beneath the dpc and the row above the dpc (which is the top row only) can quite clearly be seen.

This is a rather spectacular occurence of 'moisture' at the base of a wall but it demonstrates that the dampness has risen; until it reached the dpc.

At least that's my interpretation of it! Over to you Konrad

Patrick

 

[anobium]

I wouldn't bother Patrick, he probably bombard you with more links and photos of his website.
Talk about having a vested interest, do you not think that it is in Konrads interest to convince everybody that rising damp does not exist.!
It must be good for business to provide alternative solutions to the problem, or am I getting to cynical in my old age.

 

[jbonding]

This link shows a picture, taken this week, of a dwarf wall beneath the floor of a 1970's house.

Although the photo isn't brilliant and relies exclusively on flash for its lighting, the difference in colouration between the bricks beneath the dpc and the row above the dpc (which is the top row only) can quite clearly be seen.

This is a rather spectacular occurence of 'moisture' at the base of a wall but it demonstrates that the dampness has risen; until it reached the dpc.

At least that's my interpretation of it! Over to you Konrad

Patrick

Ive just looked and most of the bricks are all similar colours apart from the bottom course which have slight damp a couple of inches up or am i blind.

 

[Softus]

This link shows a picture, taken this week, of a dwarf wall beneath the floor of a 1970's house.

Although the photo isn't brilliant and relies exclusively on flash for its lighting, the difference in colouration between the bricks beneath the dpc and the row above the dpc (which is the top row only) can quite clearly be seen.

Not by me it can't. At least, not in the way that you describe it.

There are five brick courses illuminated by the the flashgun. From what I can see, the DPC is between courses 1 (at the top, directly below the joints), and course 2.

Half (in quantity) of the bricks in course 2 look dark, and the other half light. Many of the bricks in courses 3, 4, and 5 also look dark, and many others light.

How you can conclude anything from this photograph is beyond me.

This is a rather spectacular occurence of 'moisture' at the base of a wall but it demonstrates that the dampness has risen; until it reached the dpc.

....but it didn't stop you!

So, which are the ones that you believe to be "moist"? Just to be absolutely clear.

Also, please can you describe what is on the other side of this section of wall?

 

[PatrickD]

Hi JB

Well...I don't know about your personal problems but on my machine the top row looks a lot lighter than those beneath. It certainly did when I shone my light on it too!

However; if that's what you see, then that's what you see.

KR's

Patrick

 

[PatrickD]

Hi Annobium

No, actually I quite like Konrad and I'm basically agnostic as to whether RD exists or not. Personally I think it does but if others don't want to think that then that's up to them. The lengths Konrad goes to to prove his point is, at least as far as I'm concerned, entirely laudible and I think he does it out of belief rather than for gain.

I know I personally go to equal lengths to find other causes for dampness at the base of walls and in most cases, if you look, you'll find, but every now and again I can't find any other reason and then I say it's RD.

I do resent being told all the time that I have a vested interest in finding it though, nothing could be further from the truth. And, as my old mum used to say, "There's none so blind as those who won't see" - or something like that

Kind regards

Patrick

 

[Softus]

...a rather spectacular occurence of 'moisture' at the base of a wall but it demonstrates that the dampness has risen; until it reached the dpc.

At least that's my interpretation of it!

I'm basically agnostic as to whether RD exists or not.

Personally I think it does...

 

[jbonding]

Hi JB

Well...I don't know about your personal problems but on my machine the top row looks a lot lighter than those beneath. It certainly did when I shone my light on it too!

However; if that's what you see, then that's what you see.

KR's

Patrick

not a rising damp machine

 

[jbonding]

Hi Annobium

No, actually I quite like Konrad and I'm basically agnostic as to whether RD exists or not. Personally I think it does but if others don't want to think that then that's up to them. The lengths Konrad goes to to prove his point is, at least as far as I'm concerned, entirely laudible and I think he does it out of belief rather than for gain.

I know I personally go to equal lengths to find other causes for dampness at the base of walls and in most cases, if you look, you'll find, but every now and again I can't find any other reason and then I say it's RD. I do resent being told all the time that I have a vested interest in finding it though, nothing could be further from the truth. And, as my old mum used to say, "There's none so blind as those who won't see" - or something like that

Kind regards

Patrick

i usually say ive not got a clue or the foggyiest, abricadabra, ill be back in a minute or here is one i prepared earlier but never rising damp.

 

[ModernMaterials]

I'm really enjoying this thread and i must say, softus, that no one has proven or disproven the existence of RD to my satisfaction (although, i admit, i am seldom satisfied.)

A few years ago i was doing some carpentry for a guy who was selling his house. Whilst i was working on the gate i heard him start to drill. As he came into view around the corner i saw that he was drillling holes in the brick course above the blues. I asked him if he was getting the chemical dpc cheaper by drilling his own holes.
"No" he says, "I have no probs with damp. I just know i have more chance of getting the asking price if the buyers see these little plastic plugs in the wall" then he goes into the house and brings out a bag of brown plastic plugs to show me.

 

[Softus]

I'm really enjoying this thread...

I'm sincerely delighted to hear it - welcome to the world outside the bubble

...and i must say, softus, that no one has proven or disproven the existence of RD to my satisfaction (although, i admit, i am seldom satisfied.)

I completely agree, and am delighted (again) that you are so open-minded.

I wish it weren't so incredible that nobody can provide substantial evidence of RD. Of course the whole world doesn't read this forum, but a lot of people do.

The thing is, the bottom line as it were, is that the non-existence of RD can't be 'proven' to those who believe that it exists and who have closed their minds to any other possibility.

However, the most important thing of all is that there are those of us who would believe that RD exists if there were sufficient evidence. And there isn't. So we don't.

 

[tawelfryn]

Being a bricky by trade, I will say this, having built too many houses etc to put a figure on, I have seen, whilst work is in progress, when rain has been lashing down and trenches full of water, soaking wet blockwork/brickwork below dpc, and dry above, even when the water is a few courses below, how does it get to the dpc? It must rise, BUT on other times it hasnt either, and I don't know why. Even when you stand a concrete brick (very porous) in a pool of water, say half way, it doesn't rise no more than 10mm.
There are so many anomalies, that may or may not cause "rising damp" it could never be proved or disproved, it that case its better to have a dpc than not to be sure

 

[noseall]

tis always better to have something and not need it, than to need something and not have it.

 

[Softus]

...its better to have a dpc than not to be sure

Thanks for your interesting post tawelfryn.

I agree with your conclusion about the need for a DPC, but probably for different reasons. I have reason to suspect that an easy path for damp is on the inside of a brick wall, in the vertical layer between the brick and its covering, e.g. plaster, sand & cement, or whatever, and also, more importantly, between the brick and the slab (where there is one).

If this is the significant risk that I perceive it to be, then an easy method of mitigation is to deploy a horizontal membrane over the slab, at DPC height, and to join or overlap this with the DPC in the wall. I believe, but would be happy to be told that I'm wrong, that this is the method stipulated by the current Building Regulations.

On this premise, the important feature of the wall's DPC is to prevent the moisture that could easily rise either in the floor or between floor and wall from reaching the finished floor level, not to prevent moisture from making its mythical path upwards through the wall.