RISING DAMP - BEWARE...but not for the reasons you think!
How do you treat rising damp?
Rising damp doesn't need to be treated, it needs to be understood. It is not a defect on its own, it is caused by an accumulation of defects that present as a symptom. It cannot be cured by one treatment, no matter what the damp proofing salesman tells you.
Firstly, identify the causes of the moisture. Check external drainage for leaks or blockages, external ground levels, identify the position of the damp proof course, check seals around windows, damaged cills, mortar joints in brick or stone, cracks through render, blistering paint on render, vegetation growth through walls...many and sometimes complex defects that can contribute to what is, unfortunately commonly called rising damp.
Or simplify the process by instructing Durie Heritage to carry out a detailed survey of your property which will include a list of recommendations for repair, remedy and also maintenance.
Firstly, identify the causes of the moisture. Check external drainage for leaks or blockages, external ground levels, identify the position of the damp proof course, check seals around windows, damaged cills, mortar joints in brick or stone, cracks through render, blistering paint on render, vegetation growth through walls...many and sometimes complex defects that can contribute to what is, unfortunately commonly called rising damp.
Or simplify the process by instructing Durie Heritage to carry out a detailed survey of your property which will include a list of recommendations for repair, remedy and also maintenance.
What equipment do we use?
We use high resolution drone, thermal imaging, thermo-hygromic and calcium carbide moisture meters amongst many other pieces of equipment. We can test materials for lime content, test damp areas to determine their likely source, measure relative humidity and air quality, all as part of our normal surveys. No-one else offers this wide ranging scope. This is standard in any of our surveys.
What happens if rising damp is left untreated?
If the source of moisture is not remedied, moisture will continue to affect concealed timbers causing decay and eventual collapse of the floor. If you are extremely unlucky, it could cause dry rot, which requires a narrow band of temperature and moisture to activate, which can affect larger areas of the floor and surrounding walls including neighbours.
What are the signs of rising damp?
The signs of rising damp are decay of the floor timbers near to external walls, decay of skirting board, damp staining or loose wallpaper above skirting boards. This can also occur on internal walls which are built on similar foundations. While these are the common signs of rising damp they are NOT caused by rising damp. They are caused by external defects that are not remedied by chemical injection or damp proofing.
How do you cure rising damp?
To cure rising damp permanently is firstly by understanding the way the building was originally designed to function. To do that, you need a detailed survey report to explain it in layman's terms. A timber and damp survey from Scottish Heritage Building Surveyors will explain all this and more.
The myth that is rising damp
The Myth of Rising Damp.
Water is absorbed from its source and moves from wet to dry in a constant attempt to dry out. If the source is at ground level, moisture appears to rise, hence the term 'rising damp'. The damp-proofer's solution is to seal in the damp but without identifying or remedying the source of moisture so causing saturation.
Having been told, after an RICS building survey or homebuyers survey, that a property is damp, and been given carte-blanche to remedy the situation, these damp-proofing salesmen then recommend any treatment they like. They are, after all, being recommended by a chartered surveyor and any lender will accept their findings.
Damp proofing is a great business if you have no conscience. It is a sales-based industry, nothing to do with preservation or property care. They are not paid to provide sound advice, they are paid when they inject chemicals or hack off lime plaster to apply membranes and waterproofing plaster
The only solution that will work long-term is to reduce the amount of moisture or improve evaporation and, to achieve that, you need to know what has gone wrong to cause the dampness in the first place, often happening over decades of poor maintenance!
Damp proofers often argue that placing a sponge in a bath of water, the sponge will absorb the water. Well, how about pulling out the plug?
Water is absorbed from its source and moves from wet to dry in a constant attempt to dry out. If the source is at ground level, moisture appears to rise, hence the term 'rising damp'. The damp-proofer's solution is to seal in the damp but without identifying or remedying the source of moisture so causing saturation.
Having been told, after an RICS building survey or homebuyers survey, that a property is damp, and been given carte-blanche to remedy the situation, these damp-proofing salesmen then recommend any treatment they like. They are, after all, being recommended by a chartered surveyor and any lender will accept their findings.
Damp proofing is a great business if you have no conscience. It is a sales-based industry, nothing to do with preservation or property care. They are not paid to provide sound advice, they are paid when they inject chemicals or hack off lime plaster to apply membranes and waterproofing plaster
The only solution that will work long-term is to reduce the amount of moisture or improve evaporation and, to achieve that, you need to know what has gone wrong to cause the dampness in the first place, often happening over decades of poor maintenance!
Damp proofers often argue that placing a sponge in a bath of water, the sponge will absorb the water. Well, how about pulling out the plug?
Guarantees
Guarantees are offered by damp proofing companies but additional warranties can also be purchased.... Why an additional warranty if they guarantee their work? You may get a guarantee for a year with a new washing machine or 3 years with a new car but who can offer a 30 years guarantee on their work? It is a scam, pure and simple. Just try to claim on their guarantee then you'll find out why.
The following are just a few of the many examples of how damp 'specialist' companies or 'preservation' companies, the majority affiliated to the Property Care Association (PCA) carry out their work - with no interest in identifying defects, only in justifying covering up the symptoms.
A friend relayed a story to me about one company in Glasgow to whom they made a claim after damp proofing works failed. Another friend then told me a week later that they had made a claim a couple of months before to the same person at the same company. They were BOTH told by the same person that this company had no failures or claims in the last 20 years of trading. Can you believe it? They certainly didn't.
Unscrupulous 'damp specialist' companies rely on you, the home owner, knowing very little about how your house works and use their scaremongering tactics to pressure you into getting unnecessary, expensive and damaging work done.
One thing that has always annoyed me because no-one ever seems to question it is, even if injected damp proof courses did work:
1. What happens to the damp timbers which are built into wet wall BELOW the injection holes? and
2. How do they dry out if the conditions that caused the dampness remain unchanged?
1. What happens to the damp timbers which are built into wet wall BELOW the injection holes? and
2. How do they dry out if the conditions that caused the dampness remain unchanged?
This link is to a great article http://www.heritage-house.org/the-fraud-of-rising-damp.html about rising damp.
I can provide the following examples of properties I have surveyed myself where it is obvious that chemical intervention has done nothing but cause harm to old buildings. They were designed to breathe - please let them do so.
I can provide the following examples of properties I have surveyed myself where it is obvious that chemical intervention has done nothing but cause harm to old buildings. They were designed to breathe - please let them do so.
Despite being well injected with chemicals and having been re-plastered internally with damp-proofing plaster, the floor still collapsed.
The symptoms were covered up and never dealt with.
The symptoms were covered up and never dealt with.
It was diagnosed by a PCA CSRT damp expert that the DPC had broken down. Even though he couldn't see it.
It had actually been covered by cement roughcast and movement of moisture was possible behind the roughcast. Injecting chemicals was never going to help that.
It had actually been covered by cement roughcast and movement of moisture was possible behind the roughcast. Injecting chemicals was never going to help that.
Part buried hand access to the rainwater downpipe shows the ground level has risen. It also suggests that the sub floor vent has been moved so will be less effective at providing airflow into the solum.
It takes someone with an understanding of building pathology to identify the many and varied problems that may be causing just one symptom. |
A retired lady was charged £1,500 for an injected DPC when all it needed was a £30 spade to dig the garden down 150mm!
Rising damp? Nope, rising ground level.
Another fraudulent 'diagnosis'.
Rising damp? Nope, rising ground level.
Another fraudulent 'diagnosis'.
The result of cement outside and cement inside. The wall was saturated throughout.
Ground saturated outside a damp timber floor caused by a discharging rainwater pipe. Damp proofing will ignore this defect.
Damp wall made wetter by the application of a plastic membrane then made ineffective by the reinstatement of an electrical socket being cut through it onto the, still wet, wall causing it to rust.
One photographs tells a long, sad and expensive story.
Subsequent damp treatment salesmen installed the current best products to solve this property's damp problems over generations of dampness. It might even have been the same company, father and son perhaps.
The rectangular grilles have been placed at various positions in this structure - presumably to 'ventilate' the moisture out of the wall. This didn't work.
The triangular grilles have been placed at similar places as the rectangular grilles. This is the ground-breaking 'Knapen Atmospheric Syphon' system which revolutionised the amount of money the damp companies could make! Proved not to work!
The small holes at the bottom, which follow the same lines as the rectangular grilles and the triangular grilles, and installed by the same industry that installed the other two, is an injected damp proof course. Drilled through cement, holes left open to allow moisture to enter, the previous attempts still allowing water to enter deep into the structure - and left in-situ.... It all beggars belief.
Subsequent damp treatment salesmen installed the current best products to solve this property's damp problems over generations of dampness. It might even have been the same company, father and son perhaps.
The rectangular grilles have been placed at various positions in this structure - presumably to 'ventilate' the moisture out of the wall. This didn't work.
The triangular grilles have been placed at similar places as the rectangular grilles. This is the ground-breaking 'Knapen Atmospheric Syphon' system which revolutionised the amount of money the damp companies could make! Proved not to work!
The small holes at the bottom, which follow the same lines as the rectangular grilles and the triangular grilles, and installed by the same industry that installed the other two, is an injected damp proof course. Drilled through cement, holes left open to allow moisture to enter, the previous attempts still allowing water to enter deep into the structure - and left in-situ.... It all beggars belief.
Injected DPC to a DRY property. Sub floor ventilation blocked up behind the vent grille. No-one had bothered to look before.
This local 'preservation' company (really a joiner that had been on the 3-day course) wanted to waterproof this property internally by replastering throughout. However they would have been able to identify the reasons for the dampness if they had bothered to look outside. But maybe they did...
There were so many open joints in this building that they could not have failed to notice them, The company don't offer re-pointing - they offer damp proofing.
There were so many open joints in this building that they could not have failed to notice them, The company don't offer re-pointing - they offer damp proofing.
An injected dpc was recommended for this property! Dampness at high level below a chimney stack? Clue? Apparently not - it was never mentioned in the 'free' report. Why? Because damp and preservation companies don't do chimneys and don't understand how buildings work.
Electro osmosis- "based on the theory that...."
Like the injection of chemicals - there is the theory and there is the reality. This particular installation was half way up a basement wall to part of it. Chemical injection or Electro osmosis? it doesn't really matter - neither of them would have ever worked on this building. |
Make sure that the building is in good repair. Often I find buildings which have recently been re-pointed by well-meaning contractors who have failed to ensure that the most important areas - at ground level - have been repaired. Often there are voids, gaps filled with wet soil, weeds etc. Rising damp? No wonder!
And my specialist hand-operated-cavity-probing-depth-gauge (as damp specialist might refer to it, but I call it a screw-driver) is 150mm long. |
Often defects continue for years undetected so it is important to discover the true cause and not just re-plaster. This gable stonework was wet behind damp plaster and had been replaced around 60 years previously. The roof continued to leak - which was the original cause that wasn't identified correctly.
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New concrete floors and solid insulation with plasterboard, cement render and masonry paint outside. So why was it damp? Condensation forming in curtains and wall coverings was caused by lack of ventilation. Lime plaster internally and lime mortar or harling externally combined with sub-floor (timber) ventilation would have prevented this. Easier to heat when it's dry.
Expect rampant wet rot behind the plasterboard and to any timber built into the wet core of this property. |
Years of moisture from damp coal being dumped in an internal cupboard caused wet rot to the floor joists which allowed movement in a stone slab which failed and fell into the cellar. This is building pathology at work. Identifying problems where they exist and identifying where there are no problems but previous use of the property which caused the failure.
Would you entrust this timber failure to a damp proof specialist who would likely diagnose rising damp? |
Damp staining and smells to the external walls of this 300 year old farmhouse were solved by removing damp wall lining and the original, dry, lime plaster walls discovered behind.
The dampness caused by condensation.
The dampness caused by condensation.