biffvernon
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AJ 25/06/09 page 5
(Stephen Boniface, now where have I seen that name?)
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(Stephen Boniface, now where have I seen that name?)
Flyfisher
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Indeed.
http://www.askjeff.co.uk/rising_damp.html
I wonder how Venice gets on with 'rising damp' ?
http://www.askjeff.co.uk/rising_damp.html
I wonder how Venice gets on with 'rising damp' ?
Schoolmarm
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biffvernon said:
:lol: :lol: :lol: All hail 8) Thank goodness he is prepared to stick his neck out.
Schoolmarm
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robgil said:
OH NOI!! It is the minerologist blokey!
Lime
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biffvernon said:
Absolutely right.
The treatment for "rising damp" has either been the wholesale demolition of neglected streets and houses or totally unnecessary and ineffective vandalism to the majority of the remaining old housing stock.
Matt Green
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Excellent news, really very positive and about time that RICs took a firm line on this.
That heritage house link is not fantastic advert though, this mis-understood over-application of Occam's razor undermines the argument:
".. and just to ram the point home - this is the millrace, at the hotel I stayed at. The wall above the water surface is bone dry - that's the restaurant wall you're looking at!. Damp proofing companies tell you water magically 'rises' a metre up the wall - why a metre I wonder?"
Argh! No! Don't show picures of brickwork around water courses and proclaim rising damp doesn't rise. Claiming that 'rising damp' (defined as the movement of water up through a wall with no other cause than capillary action) doesn't exist, therefore capillary action doesn't exist is crazy. If you plastered that brickwork around the millrace you'd start seeing signs of damp damage on the plaster pretty quickly because it would impede evapouration through the wall surface. If a core sample was taken from that brickwork, it would not be dry even if the surface is. The large amount of water is not doing any damage though, because its passing straight through the bricks.
And why 1m? Because on a wall covered with modern (non-lime) plaster at about 1m up the wall the water lost through the plaster is equal to the water being pulled up through cappillary action. There's plenty of photos that show that water moves upwards through a wall if you block the means for it to escape. There needs to be emphasis as to why any damage seen does appear, not simply claiming that it can't exist- otherwise credibility is lost.
M.
That heritage house link is not fantastic advert though, this mis-understood over-application of Occam's razor undermines the argument:
".. and just to ram the point home - this is the millrace, at the hotel I stayed at. The wall above the water surface is bone dry - that's the restaurant wall you're looking at!. Damp proofing companies tell you water magically 'rises' a metre up the wall - why a metre I wonder?"
Argh! No! Don't show picures of brickwork around water courses and proclaim rising damp doesn't rise. Claiming that 'rising damp' (defined as the movement of water up through a wall with no other cause than capillary action) doesn't exist, therefore capillary action doesn't exist is crazy. If you plastered that brickwork around the millrace you'd start seeing signs of damp damage on the plaster pretty quickly because it would impede evapouration through the wall surface. If a core sample was taken from that brickwork, it would not be dry even if the surface is. The large amount of water is not doing any damage though, because its passing straight through the bricks.
And why 1m? Because on a wall covered with modern (non-lime) plaster at about 1m up the wall the water lost through the plaster is equal to the water being pulled up through cappillary action. There's plenty of photos that show that water moves upwards through a wall if you block the means for it to escape. There needs to be emphasis as to why any damage seen does appear, not simply claiming that it can't exist- otherwise credibility is lost.
M.
chuckey
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As most materials in the carcass of a building contain water molecules, all could be defined as damp. So the definition of "dampness" to the layman should run along the lines of :- "damp is defined where the amount of water in a material or structure affects the decoration or leads to the rotting of wood or produces the smell of mustiness". So if you can't see it or smell it and your wood work is not rotting, you have not got "damp".
So if the internal ventilation is high and the woodwork tolerent of a high moisture level and there is no gypsum plasters (which a intolerent of water), like in a castle it is almost impossible to have rising damp, the water content of the structure may be high, but you can't see it, smell it etc.
On the other hand in a modern building with inadequate ventilation, so the water content of the structure is high due to condensation, and with poor woodwork and gypsum plaster, any increase in the water load of the structure due to capillary action of water from the ground, leads immediately to damp patches at the base of walls which is the dreaded ring damp and will cause the woodwrk and plaster to fail prematurely.
As new houses have an almost impervious DPC (if installed properly) "rising damp" should all but disapear, however with the insertion of masses of impervious sheet insulation material with in the wall construction, and the general attendance to the air tightness of structures, interstitual condensation will be the next problem. This is where condensation occurs within the thickness of a multi layer wall and can rot wood and be totally unseen and undectectable until some catastrophic failure.
So does "rising damp" occur? - yes, is it a big problem?, can be in badly built houses but in general - no. One caveat is that there is not a large amount of salts being transferred by the rising and evaporating water. This is a huge problem in certain parts of Australia, where the deposited salts actually crack bricks and can lead to structural failure of a wall.
Frank
So if the internal ventilation is high and the woodwork tolerent of a high moisture level and there is no gypsum plasters (which a intolerent of water), like in a castle it is almost impossible to have rising damp, the water content of the structure may be high, but you can't see it, smell it etc.
On the other hand in a modern building with inadequate ventilation, so the water content of the structure is high due to condensation, and with poor woodwork and gypsum plaster, any increase in the water load of the structure due to capillary action of water from the ground, leads immediately to damp patches at the base of walls which is the dreaded ring damp and will cause the woodwrk and plaster to fail prematurely.
As new houses have an almost impervious DPC (if installed properly) "rising damp" should all but disapear, however with the insertion of masses of impervious sheet insulation material with in the wall construction, and the general attendance to the air tightness of structures, interstitual condensation will be the next problem. This is where condensation occurs within the thickness of a multi layer wall and can rot wood and be totally unseen and undectectable until some catastrophic failure.
So does "rising damp" occur? - yes, is it a big problem?, can be in badly built houses but in general - no. One caveat is that there is not a large amount of salts being transferred by the rising and evaporating water. This is a huge problem in certain parts of Australia, where the deposited salts actually crack bricks and can lead to structural failure of a wall.
Frank
Now, I think I actually do have rising damp (e.g. in my hall, the skirting boards are rotten and the plaster behind them up to about 30cm high has crumbled away.) , but am willing to accept that this may not be the case. BUT my mental definition of rising damp is not that there is water rising up the walls, but that the water in the walls is causing a problem because it's trapped there and can't get out. So is does this for once count as rising damp? I suppose it could be condensation condensing at the bottom of the walls, but the worst of the rotten wood is actually well within the walls, not on the outside of the walls.
Having said that, during my last hairdresser's appointment I spent 40 mins telling the woman at the next seat (who I know slightly) that she probably didn't have rising damp in her kitchen, already had a DPC anyway so didn't need another one, and that she needed to sort out the condensation problems.
Having said that, during my last hairdresser's appointment I spent 40 mins telling the woman at the next seat (who I know slightly) that she probably didn't have rising damp in her kitchen, already had a DPC anyway so didn't need another one, and that she needed to sort out the condensation problems.
Stephen
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I was never Chair of the RICS - I was merely Chair of the Building Surveying Faculty, but am grateful that the AJ seek to promote me. 
(am waiting RICS to contact me and have a go though! )
The quote is a slight distortion of what I actually said (isn't that always the way with journalists).
The problem here is one of semantics.
Rising Damp is a term used by the public and by the professions to label almost any form of damp found at low level in a wall.
I have often said (as Matt has stated) that damp can rise up walls, but generally only in specific situations (where uptake is greater than evaporation - in simplistic terms) and then more often by capillary action.
The point of my message is that we need to start disagnosing damp properly and identifying what really needs to be done rather than reliance on the treatment industry (in my view the biggest rip-off in the construction world). To get this message across if it means stating that Rising Damp doesn't exist to grab attention then so be it. When we get down to it what I am really after is proper diagnosis and appropriate remedial works (rarely, if ever, treatment).
Stephen
(am waiting RICS to contact me and have a go though! )The quote is a slight distortion of what I actually said (isn't that always the way with journalists).
The problem here is one of semantics.
Rising Damp is a term used by the public and by the professions to label almost any form of damp found at low level in a wall.
I have often said (as Matt has stated) that damp can rise up walls, but generally only in specific situations (where uptake is greater than evaporation - in simplistic terms) and then more often by capillary action.
The point of my message is that we need to start disagnosing damp properly and identifying what really needs to be done rather than reliance on the treatment industry (in my view the biggest rip-off in the construction world). To get this message across if it means stating that Rising Damp doesn't exist to grab attention then so be it. When we get down to it what I am really after is proper diagnosis and appropriate remedial works (rarely, if ever, treatment).
Stephen