Rising Damp - Fact or Fiction?

K

kettlemanjim

I've read claims that there is no such thing as "Rising Damp" and that there's much disinformation surrounding this topic. Could someone with real world building experience please explain the true fundamental with regards to this.







Netherlands
 
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Peter Ward on YouTube.

Whilst I think that at times he goes a bit OTT, his logic I think is sound.
 
That's the chap I've been reading about.
 
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So you are basing your opinion on one bloke you've seen on YouTube? Who incidentally is trying to sell his damp inspection service. He is a very good salesman but you need to take what he says with a large pinch of salt and some of it is just wrong.

Why not do some wider research from independent reliable national organisations such as the Building Research Establishment, British Standards Institute etc. Why not read part C of the Building Regulations or is the requirement for walls to have a damp proof course a "myth". Read guidance from the RICS, RIBA etc.

Failing that build a house without a damp proof course and see what happens, I'll give you a clue, it rhymes with lamp.

In my opinion rising damp does exist. Bricks are porous and will draw moisture upwards by capillary action. It has been widely misdiagnosed over the years by some unscrupulous damp proofing contractors and it does not always need expensive remedial treatment in older houses but that does not negate the basic principal that brickwork can transmit moisture vertically.
 
I think Wessex nails it above, it does exist, but I would guess the majority of rising damp diagnosed in solid wall houses is not rising damp.
 
In my opinion rising damp does exist. Bricks are porous and will draw moisture upwards by capillary action.

But not far.

Clean brickwork, without plaster, render, or rubble in the cavity, exposed to the air... just two courses or so.
 
But not far.

Clean brickwork, without plaster, render, or rubble in the cavity, exposed to the air... just two courses or so.

You cannot make a sweeping generalisation like that. It depends on the porosity of the brick and the levels of moisture in the ground. I've seen very porous bricks in very wet ground suck up the moisture to a couple of feet. Likewise I've seen a very dense brick in very dry ground barely take up any moisture at all.
 
Why not do some wider research from independent reliable national organisations such as the Building Research Establishment, British Standards Institute etc. Why not read part C of the Building Regulations or is the requirement for walls to have a damp proof course a "myth". Read guidance from the RICS, RIBA etc.
Why do they manage without them in other countries?

In my opinion rising damp does exist. Bricks are porous and will draw moisture upwards by capillary action. It has been widely misdiagnosed over the years by some unscrupulous damp proofing contractors and it does not always need expensive remedial treatment in older houses but that does not negate the basic principal that brickwork can transmit moisture vertically.
rd2.jpg
 
perhaps the pore size is different in lime mortar or in your local brick.

Capillarity causes water to move up porous, wettable material. It will easily move from large pores to small, but not easily from small pores to large. So brick to mortar, then mortar to brick, is difficult to achieve. That's why two courses of brick, and two beds or mortar, with no render, plaster or rubble in the cavity, make a useful barrier. If the brick is exposed to the air, a point is reached where evaporation from the surface equals absorbtion from below.

You'll see the same thing in laboratory tests of brick piers standing in water.
 
Why do they manage without them in other countries?


rd2.jpg

Blimey you've been busy getting indoctrinated by Peter Ward.

He says they don't have DPC's in the Netherlands ... that is a big fat lie. The only difference is they tend to use a waterproof grout or additive in the mortar to create a damp proof course rather than a physical membrane.

Likewise his photo above. What is the construction of that wall? How do you know there isn't a DPC? How do you know what the normal water level is? How do you know they didn't use a waterproof additive in the mortar? Just a photo on it's own with no background information or context is pointless.

But it obviously works for Mr. Ward because you fell for it hook line and sinker.
 

That is not a "laboratory test" and has been widely de-bunked.

Ask yourself the question, How many houses have I seen that are built with just small isolated brick piers of fairfaced flettons only 6 courses high and exposed on all sides? I can honestly say none.

With that example the evapouration from all four sides and the top far exceeds the hydrostatic pressure and capillary action drawing the water up from the base.

If you lived in a house where the wind whistled through huge gaps in the walls and you had no internal finishes you probably wouldn't see the symptoms of rising damp either. Although you'd probably die from pneumonia long before you had time to worry about the damp. That's what makes me laugh about all this "heritage house" nonsense. Back when people used to accept living in damp draughty houses with outside toilets and cooking on a solid fuel range they would probably die in their early forties because of the dreadful living conditions. It shouldn't be a modern day aspiration to live in Victorian slum conditions.

Personally I'd rather live in a house with proper walls and a floor and windows and plaster on the walls and a roof, an indoor privy, hot water on tap and central heating.

I'm still waiting for one of these Peter Ward disciples to put their money where their mouth is and actually build a house without a DPC then I might be a convert.
 
Rising damp is real
If doesn't always happen
When it does happen, it doesn't always happen immediately

Depends on how porous a brick or stone is, pore size, type of water, time.

In a brick in contact with water, water will wick up. But if pores are large, gravity will drain water down faster than it can rise. But, over time salt build up blocking pores, and the gravity starts to lose, and water wins. Rising damp . Well ventilated bricks will also dry out faster than unventilated, which is why photos of bricks in buckets don't always show rising damp.
 

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