I recently read a book called "dampness in buildings" by T.A Oxley anyone read it? //www.diynot.com/forums/viewtopic.php?p=1582758#1582758
Rising damp does not exist
- Thread starter Softus
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This was priceless.
Capillary action is caused by hydrogen bonding and has nothing to do with the earth's force-lines. In water, the angle subtended by hydrogen-oxygen-hydrogen nuclei varies but is about 105 degrees. The covalent electrons spend more time near the oxygen nucleus and consequently, each hydrogen atom carries a positive charge equivalent to about a third of a proton and the oxygen atom carries a negative charge equivalent to about two thirds of an electron. The result is that the hydrogen atoms are attracted to oxygen atoms of adjacent molecules - hydrogen bonding. Frequently (about every 1ms on average in pure water), each water molecule will lose a hydrogen nucleus, which becomes a free proton, leaving behind an hydroxide ion. These protons can go on to attach to other hydroxide ions. The concentration of these free protons is measured in pH (acids and alkalis).
Water is not the only substance that exhibits hydrogen bonding and is attracted to those substances. I agree with that bit. The 'balance' is generally between capillary action and evaporation.
OMG, I've just re-discovered this site and can't believe I've missed all the action of this thread.
Did you know the root system of trees is only there to hold the things down. (Stops them floating away in times of high atmospheric density.) Some people think that they draw moistue up to supply the tree. What tommy rot, don't they know rising damp doesn't exist.
For a trees root system to work it would have to have exactly the same pore size as the soil in which it's planted as Konrad pointed out. Bearing in mind trees grow in all types of soil it's never going to happen is it?
Softus you're a superstar!
Did you know the root system of trees is only there to hold the things down. (Stops them floating away in times of high atmospheric density.) Some people think that they draw moistue up to supply the tree. What tommy rot, don't they know rising damp doesn't exist.
For a trees root system to work it would have to have exactly the same pore size as the soil in which it's planted as Konrad pointed out. Bearing in mind trees grow in all types of soil it's never going to happen is it?
Softus you're a superstar!
What part of a tree is the Tommy
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Old topic, I know, but having read it there are a few points I just cannot get my head around.
The principle behind water failing to rise, by capillary action, through a wall made of brick and mortar, is that the capillary size of the brick and mortar do not match, as capillary action can only continue from a wider capillary to a narrower capillary the action fails as you move from the brick layer to the mortar layer.
Now water can rise behind plaster or through plaster because the plaster represents one continuous vertical layer of matching capillary size, and from the plaster the bricks are saturated via a horizontal absorption of water from the plaster.
All making sense so far.
However, there is one error in all this thinking, irrespective of the presence or not of a vertical wall covering, the mortar alone represents one continuous and uninterrupted material from ground to ceiling, the horizontal inter-brick mortar is in contact with the vertical mortar and as it is the same material it has the same capillary size. Imagine your house, you can place your finger on the pointing at floor level and run all the way to your roof without ever once having to cross another material, take your finger off the mortar or anything of the kind. What is it that prevents the mortar alone wicking water up from the base of the wall and saturating the bricks?
Now of course I have no first hand account to offer and consider myself a RD doubter, I just don't understand this point.
The principle behind water failing to rise, by capillary action, through a wall made of brick and mortar, is that the capillary size of the brick and mortar do not match, as capillary action can only continue from a wider capillary to a narrower capillary the action fails as you move from the brick layer to the mortar layer.
Now water can rise behind plaster or through plaster because the plaster represents one continuous vertical layer of matching capillary size, and from the plaster the bricks are saturated via a horizontal absorption of water from the plaster.
All making sense so far.
However, there is one error in all this thinking, irrespective of the presence or not of a vertical wall covering, the mortar alone represents one continuous and uninterrupted material from ground to ceiling, the horizontal inter-brick mortar is in contact with the vertical mortar and as it is the same material it has the same capillary size. Imagine your house, you can place your finger on the pointing at floor level and run all the way to your roof without ever once having to cross another material, take your finger off the mortar or anything of the kind. What is it that prevents the mortar alone wicking water up from the base of the wall and saturating the bricks?
Now of course I have no first hand account to offer and consider myself a RD doubter, I just don't understand this point.
Amphibian makes a very valid point here i think, and one that i've been wondering about myself. Can anyone answer it?
I consider myself an 'RD doubter' as well, so i'd be quite happy for someone to successfully explain it.
As well as that, there is this:
http://www.palgrave-journals.com/jba/journal/v6/n1/full/jba201013a.html
If you read it, it seems Mr Ralph Burkinshaw has successfully (and surprisingly easily
) demonstrated damp rising through brickwork.How has he done this when Jeff Howell couldn't, and that guy on the BBC documentary (he wasn't Howell was he?) claimed he used lots of different mortar mixes - did it never occur to him to try a lime mix?
I'm a bit puzzled as to how the debate can rage for so long only to (seemingly) be easily solved by an experiment i could've, with a bit of effort, carried out myself!
Surely there must be something a bit funny going on?
Softus? Konrad?
Thanks to anyone who takes the time to respond, or is it time to silently retreat?
No.
That was not an original points by Amphibian - it was one of my points from The Very Beginning. Of course damp can rise between rendering and/or plastering and the brickwork - this is one of the many things that can be cured by replacing blown render, and by stopping water from getting behind the render in the first place.
I'll take a look at that link and hope that finally someone has managed to demonstrate the rising damp through brickwork exists.
http://www.architectsjournal.co.uk/...a-myth-says-former-rics-chief/5204095.article :
"Stephen Boniface, former chairman of the construction arm of the Royal Institution of Chartered Surveyors (RICS), has told the institute’s 40,000 members that ‘true rising damp’ is a myth and chemically injected damp-proof courses (DPC) are ‘a complete waste of money’."
http://webcache.googleusercontent.c...amp&cd=6&hl=en&ct=clnk&gl=uk&client=firefox-a :
"Anyone who has bothered to read Jeff Howell's book "The Rising Damp Myth" will know that the damp test pillars referred to were built using the special mortar developed at the BRE in order to artificially create rising damp. This mortar was basically chalk and brick dust - unlike any mortar used in real brick walls. He explains in the book how the existence of these special pillars has been deliberately misinterpreted by the damp-proofing industry in a pathetic attempt to discredit his research. You should read the evidence in Jeff Howell's book, and then make up your own mind. Graham Coleman is employed by the damp-proofing industry, and therefore has a big vested interest that he has not declared."
"Stephen Boniface, former chairman of the construction arm of the Royal Institution of Chartered Surveyors (RICS), has told the institute’s 40,000 members that ‘true rising damp’ is a myth and chemically injected damp-proof courses (DPC) are ‘a complete waste of money’."
http://webcache.googleusercontent.c...amp&cd=6&hl=en&ct=clnk&gl=uk&client=firefox-a :
"Anyone who has bothered to read Jeff Howell's book "The Rising Damp Myth" will know that the damp test pillars referred to were built using the special mortar developed at the BRE in order to artificially create rising damp. This mortar was basically chalk and brick dust - unlike any mortar used in real brick walls. He explains in the book how the existence of these special pillars has been deliberately misinterpreted by the damp-proofing industry in a pathetic attempt to discredit his research. You should read the evidence in Jeff Howell's book, and then make up your own mind. Graham Coleman is employed by the damp-proofing industry, and therefore has a big vested interest that he has not declared."
This thread is almost 7 years old and just won't die.
For what it is worth, over 25 years ago I was working for a local authority when renovation grants and improvement areas were at a high. I saw many examples of what I believe were rising damp. In addition I believe the problem was often aggrevated by condensation. I also saw many cases where I believe the dampness was simply condensation.
One of the interesting aspects of the job was the council policy to provide injection DPC's to all terraced properties in an improvement area. The idea was that if all the terraced houses in a street were treated then the party walls got sorted, and the system should work properly.
It would be very interesting to visit those streets again to see the condition of the walls inside now.
I have witnessed injection damp proofing being carried out incorrectly so I have no doubt that some so called treated properties have not in fact been treated as the system requires. Likewise seeing the treated bricks bridged by following trades is another common failing.
I certainly believe rising damp is a very real problem. I don't believe all cases of low level dampness are rising damp simply because it is low level.
I recently visited a house where the owner was renovating. One question put to me was should he do an injection DPC. I went on to explain only if there is a rising damp problem, not because because it is an old house. Generally after looking at the property I concluded it didn't really have a rising damp problem, but did have some low level dampness due to the raised external ground levels almost burying all the blues courses it originally had showing. So the less resistant facings were now getting saturated when it rained and it was probable that with the solid 9" walls some penetrating damp was occurring low level. While this was my opinion only, it is yet another reason why I think each case has to be taken on it's merits after close inspection and taking all factors into consideration. My advise was that he should spend his money on correcting the (locally raised) ground levels. Incidentally I was not doing any work for him so have no vested interest in groundworks!
For what it is worth, over 25 years ago I was working for a local authority when renovation grants and improvement areas were at a high. I saw many examples of what I believe were rising damp. In addition I believe the problem was often aggrevated by condensation. I also saw many cases where I believe the dampness was simply condensation.
One of the interesting aspects of the job was the council policy to provide injection DPC's to all terraced properties in an improvement area. The idea was that if all the terraced houses in a street were treated then the party walls got sorted, and the system should work properly.
It would be very interesting to visit those streets again to see the condition of the walls inside now.
I have witnessed injection damp proofing being carried out incorrectly so I have no doubt that some so called treated properties have not in fact been treated as the system requires. Likewise seeing the treated bricks bridged by following trades is another common failing.
I certainly believe rising damp is a very real problem. I don't believe all cases of low level dampness are rising damp simply because it is low level.
I recently visited a house where the owner was renovating. One question put to me was should he do an injection DPC. I went on to explain only if there is a rising damp problem, not because because it is an old house. Generally after looking at the property I concluded it didn't really have a rising damp problem, but did have some low level dampness due to the raised external ground levels almost burying all the blues courses it originally had showing. So the less resistant facings were now getting saturated when it rained and it was probable that with the solid 9" walls some penetrating damp was occurring low level. While this was my opinion only, it is yet another reason why I think each case has to be taken on it's merits after close inspection and taking all factors into consideration. My advise was that he should spend his money on correcting the (locally raised) ground levels. Incidentally I was not doing any work for him so have no vested interest in groundworks!
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