The Rising Damp Myth Exposed? Roger's Rant!

Roger is back on to rising damp and asks the question...

... is rising damp a myth?

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#RisingDamp #Damp #MythBusting

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[thegrandmuftiofwakanda]

Rising Damp is not a myth. I've seen a few episodes and thought Leonard Rossiter was absolutely fantastic.

[PeterrAre]

Quite a balanced view Roger. Most older housing stock remaining in London was built without damp-proof courses or cavity walls and in the main stays remarkably dry. But ground levels have risen after various owners lay yet another layer of paving over old, until outside paving is level with inside floors. Walls are rendered and painted instead of being left to breathe. Chimneys blocked up and plastic windows installed. Overoccupation of ever decreasing sized properties then pours water vapour into what has effectively become a plastic bag. Cooking on gas releases even more water vapour. Result is condensation, as you described so well, on the colder surfaces. The rising damp myth a book by Jeff Howell the building science lecturer does put a big hole in the damp proofing industry but the RICS are equally to blame for allowing their surveyors to hide behind their damp meters most of whom have no idea of their serious limitations.

[edwardkopczyk]

It isn't that it doesn't exist it is more that it is often misdiagnosed

[thephoenixscotland]

I think the problem was with the rising damp industry is they were a lot of scam artists that attributed all damp as rising damp and charged thousands to solve a problem that wasn't there. It was condensation or penetrating damp, especially in old building where the outside ground level had built up above the hard brick course or above vents.

[TomTomTomTom]

I don't think anyone really believes that rising damp is a myth do they? It's just that 90% of damp cases are not rising damp. I've even seen cases where there is a perfectly good original slate damp proof course and some damp roof cowboy has drilled holes all above it to 'treat'. And of course it didn't fix the issue because it was a high ground level and breathability issue

[diddywright]

I have a customer with a small mould issue, no trickle vents, clothes dried on radiators, north facing gable with cracked render, etc etc. Gave the customer some advice, but he opted for getting a plasterer in who hacked off the first metre and then reinstated it, a practice synonymous with rising damp. Only issue is it’s a second floor flat!

[lrdisco]

The source of damp is where the confusion comes in. A lot of time it's poor ventilation or penetration.

[bobjoatmon]

British terminology : rising damp
Rest of world and science : capillary action (or wicking)

[davep]

As a Building Surveyor, I don't think I've ever met any qualified surveyors who would argue that rising damp doesn't exist at all, just lots who (I would say rightly) believe that the cause of the damp is usually more likely to be something else.... i.e penetrating damp from the exterior, raised exterior ground levels, poor ventilation of underfloor voids, poor choice of plaster/render material, condensation etc etc.

The chemical DPC industry is still a bit of a racket, in my view. I have never specified one, though I would never rule it out completely, i'd just want to try lots of other things first!

Some of the confusion comes, I believe from some research which was done some years ago at London South Bank University, where they were not able to recreate rising damp in lab conditions. Clearly, lab conditions are not necessarily indicative of the real world, and I took the outcome of the research to be that water moving upwards via capillary action is simply a lot less common than some people think.

[scottstewart]

Ah Venice, a place where the rising damp is so bad, they use gondolas for transport on it.

[Panoolied]

Buildings need to breath because of the condensation caused by people living in it. Trapped condensation - trapped by modern "damp proofing" methods. It's almost always never actual rising damp, that's the reason given for expensive remediation work.

[brawnr]

In the distance I can hear Peter Ward exploding.

[nickbarber]

I've renovated a few houses now and had to remove bricks behind skirting to access the cavity to scrape out cement snots. Worse on houses built 100 years ago with lime as some of the lime crumbles down over time. I then attatach a length of waste pipe to a Henry vacume cleaner and suck it all out.

[Moultonist]

Britain’s expert and guru on damp
In buildings is Pete at Heritage House Building and Restoration. He’s an RICS conservation surveyor. I recommend reading their website and watching the videos. It’s eye-opening and very informative. He should be given an award for his relentless exposure of unnecessary remedial works and the real causes of damp. Actually, he doesn’t really believe in rising damp!
And incidentally, why show Venice as proof of rising damp? It’s built on water! Most British Homes at worst, would sit on slightly damp soil for part of the year.

[chrisb]

I think you’ve missed the point.

Moisture will only wick up a porous material. If you put an engineering brick in a bucket of water the exposed bit will stay dry as opposed to a thermalite block which the water will travel up. Same story with mortar, Portland cement is pretty much waterproof.

As you say, almost any structure built in the last 200 years has a DPC whether slate or plastic.

I’ve yet to come across a building that was actually suffering from riding damp. It’s always been raised ground levels outside, poor drainage/gutters, leaking pipes etc, drying washing inside, modern showers, leaking roofs.

Most of it can be solved by simple stuff like lowering ground levels. Dealing with rain water ventilation etc.

So in a way I’d agree rising damp is a myth.

The products like dry rods, injection creams, galvanic system etc are 100% snake oil.

[allotmentuk]

As a building surveyor for over 40 years I did 15 inspections a day for 4 days a week 1 day writing reports. Of those average 15 inspections three quarters would be to inspect rising damp lets say 10 inspections for rising damp of those inspections only 1% would be water penetration. The test used is one that is accepted by the courts or arbiter A discreet hole is bored in the affending section of wall and the colour of the dust is registered ie if the dust becomes lighter it is condensation. If the dost becomes darker it is water penetration. If it went darker it is water penetration. The then would be weighed and then subjected to a gas pressure vacuum and the dust re weighed establishing a penetration ratio the water is tested 1st for chlorine if present it is domestic water, then for glycerene which shows it is from a leaking central heating system then it is tested for traces of effluent which would indicate a broken drain. We are advised not to use the term rising damp as this implies water traveling vertically. Water is very heavy and for it to go vertical it must be pumped. There is an argument it can be drawn by capillary attraction so is it through the brick is the brick a soft porus brick or is it travelling through the joints? At Building college built dwarf walls using different bricks bult in galvanised trays never observed water travelling upwards except when more water was put in the tray. Seen plenty of water penetration usually poor cavity trays, parapet walls. Most of my work was by the Thames some of the structures 2, 3 maybe 4 hundred years old Sam Pepys office at the old Deptford Navel yard comes to mind, no damp course, snuff dry. Of Course the well built survives the dross goes into history. I think water penetration is a better word Rising Damp is a television programme. Good rant though.

[Niall]

Great video Roger, I'm a Chartered Structural Engineer and you were able to sum up the issues at hand here in a very concise way.

[stephencooper]

Bought my house (1930’s three bed terrace) about 9 years ago.

Was told by surveyor that it had rising damp (rotten floors, damp walls ect)

On closer inspection the exterior ground levels had risen above the damp proof course

Took ground levels back down fixed all damage caused problem solved 👍

[paultaylor]

If there's no such thing as rising damp, how about 'falling damp?' That's usually caused by leaking roofs or faulty plumbing. Using a meter, rising damp can be detected in walls quite easily. Love the botany lesson, Roger. David Attenborough, watch out. Very informative post as an analytical chemist myself, now retired, the use of silicone fluid to help damproofing courses more effective still interests me. My house is a 90 year old 3 bed semi, built with Accrington brick, one live chimney and central heating. There are now issues with rising damp 40 years after the DPC was done, time to call in the experts for a survey.

[BartoszTabaka]

Pizza+beer+Roger rant=ultimate evening