Rising Damp - Problems with Identifying it
It doesn't sound like a particularly interesting topic, however a quick search on the worlds favourite internet search engine will show that in some circles rising damp is a very hot topic indeed. The trouble is that it appears that it could indeed be some type of religion or god; does it exist, or doesn't it? The truth of the matter is that rising damp does indeed exist in one form or another, but it is often misdiagnosed, or you can often pay for expensive 'rising damp treatment' that really isn't necessary.
What is Rising Damp?
Problems Caused
How to identify it
What to do about Rising Damp
What is Rising Damp? Back to top
So what is rising damp? Rising damp in buildings may be defined as the vertical flow of water up through a permeable wall structure, the water being derived from ground water. The water rises through the pores (capillaries) in the masonry by a process loosely termed "capillarity." In other words the masonry acts like a wick The common causes are deterioration due to age and bridging of a damp course with internal concrete floors, renders or external paths and earth levels (a damp course is specifically designed to avoid the possibility of rising damp- it is built of a matter of course in all new buildings).
Problems Caused by rising damp Back to top
If your house does indeed have rising damp (something we will discuss later) then it can cause the following problems:
For inside walls
- Paint does not adhere to the wall.
- Wall paper lifts and stains appear on the walls.
- Plaster flakes away, feels soft and spongy, bubbles and white powder or crystals appear.
- Skirting boards and floor boards rot.
For outside walls
-Mortar frets and falls out between bricks and stonework.
-Stains or white powder appear on walls.
These problems are mainly aesthetic problems only, however it is conceivable that structural damage could result from extensive rising damp, and of course a damp mouldy environment could pose a health risk to people.
How to Identify Rising Damp (or how not to) Back to top
Obviously if you have any of the above symptoms then it is possible that your home is suffering from rising damp, and it would be advisable to get an 'expert' in to look at your home. However this is where you will face a major problem; who is an expert on rising damp, and who is just a 'cowboy' out to diagnose you with the "worst case of rising damp that he has ever seen, which can only be solved with the most expensive treatment on the market"? Unfortunately there are a lot of companies out there who have targets to meet and profits to make, and the way they do this is by over zealously diagnosing rising damp, and charge you hefty fees for carrying out work that may, or may not, fix the problem. The major problem is that any 'damp-proofing salesman' that you employ to look at your home will use a 'rising damp meter'. These meters are supposed to measure the moisture in materials, however what they actually do is measure the electrical conductance. The idea being that the better the conductance (the ease at which electricity flows) the higher the water content. However these meters can only be calibrated for one material, and that is usually timber. So they will give reasonable results for wood and possibly some plasters, but for bricks, wallpaper and concrete they will give readings that are way too high. Thus they can be used (by unscrupulous salespeople) to indicate that you have rising damp "because the meters says so" when in fact you have a perfectly normal wall.
In summary if you can visibly see a problem with your wall, with obvious signs of damage due to water or salty tide marks then you may have a problem with rising damp, and you will need to try to find a reliable expert to come in and look at your problem. However be very, very wary of any 'expert' who has been employed to do a general survey of your house, or indeed comes around offering a free check up of your building. If they pull out one of these 'moisture' meters, jab it into the wall a few times and declare that you have a major problem, then it is entirely possible that they are a commission based salesperson trying to extract money from you. Generally with rising damp, if the wall looks OK, it is OK. If it looks like it is damp, mouldy or has tide marks on it, then you have a problem with moisture, condensation, or rising damp in your home, and you need to investigate things further.
What to do about Rising Damp Back to top
If you are convinced that you do indeed suffer from rising damp then there are a plethora of companies out there that offer ways to fix your problem. There appear to be a lot of companies offering a chemical spray treatment of one kind or another that is supposed to soak into the walls and prevent any moisture from entering the brick work. Although the author of this article hasn't investigated these types of treatment in detail he feels that these courses may not be the best solution. These chemicals rarely penetrate very deep into the brick work and can in fact make matters worse by preventing the moisture from evaporating out of the brickwork. A better solution is to look at the details of your damp-course (this is usually a physical plastic sheeting placed need the bottom of your brickwork) that you have installed in your home, and look at either creating one, or repairing it if it is damaged.
"Rising Damp - Its effects, damage caused, and how to treat it" by Alastair Taylor
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Date Added: Tuesday 1st December 2009
"Interesting and helpful stuff, thank you. I also have a question: my two-storey semi, with cavity concrete walls, has suspended wooden floors. I strongly suspect that the early 1970s builder took shortcuts under the suspended wooden floors. While the walls are dry we always have a damp smell, especially in winter, and our dehumidifiers constantly collect water; I suspect this is moisture seeping up through the floors. I am seriously considering replacing the ground floors with concrete. How can I avoid the cure being worse than the disease? Is it feasible to lift all the floors boards and put in a membrane before replacing the wooden TnG? Or is it advisable to put in a membrane and replace the entire floor(s) with concrete?"
Noel Brennan
Date Added: Wednesday 18th November 2009
"I have ahouse that neds refurbishing and |I probably like you all find the damp issue the hardest- I have damp parts and defective render-ouside .I have had expensive quotes for a chemical damp course - also a quote for the holland bricks system. I find it hard do i let the house breathe-it has had no central heating either to dry it out.I ned to decide about kitchen and bathroom area. "
P Ralph
Date Added: Sunday 15th November 2009
"I have lived in a flat for over 4 years all my bedrooms have dampness on all the exterior walls under the windows and my kitchen as well i have mould on my wardrope doors an my clothes smell an are often damp I have 3 children every year at the same time my children start to get unwell i have asked the council about this an they treat it with antifungal paint it's ok for a short time then it re appears again an again they said the problem is caused by not usin the proper heatin in the house but i don't think this true my mum has the same source of heating an doesn't use the bedroom heaters as they are too expensive to run. I am at the end of my tether with this problem i have electric heating which is costin £70 a week just now which i can't afford as i am on benefits does anybody know what to do an what could help "
lisabeattie
Date Added: Thursday 5th November 2009
"Your comments were really useful, but as a Qualified Surveyor, and Builder, maybe a bit oversimplified. Not all Damp Meters are cheap and nasy, (as Opposed to the builders who are nice but extortionate!). Their is a wide variety of tanking and injection methods available and the more you read, the easier your own soluition will get. Personnally I dont like chemicals and prefere the Electric Osmotic Damp Proof Course method. Simply a titanium wire with an trickle electric charge running through it. Endorsed it by using it on my own house. A little trick for getting rid of the black mould is a strong Lavender Oil (about ten drops mixed with water in an old sprayer) spray on an leave. wear rubber glovers and wipe away with a dry towel or kitchen towel. clean and contrinue arounmd three times, and you will see a big difference"
Stephen P McCluskey
Date Added: Wednesday 19th August 2009
"As the other guy said. Damp proofing is a scam! Get an independent CHARTERED building surveyor to look at the problem. It is not surprising that a "surveyor" who has had little training other than maybe a week long course finds damp in your home. It is also not surprising that rather than finding out where the water is coming from he just assumes you have rising damp and you need expensive injection and re-plastering works. The Building Research Establishment and every expert in the country have never been able to prove a genuine case of rising damp. It is almost impossible to reproduce under laboratory conditions also - so what does that tell you? One last thing I suppose I should mention is that these "surveyors" only use a very basic meter called a resistance meter - or a "stab" meter as they are known. They only tell you how easily the wall conducts electricity and not how damp it is! They are also only designed to be used in timber, on things such as skirting boards. This method of testing will not prove that a wall is even wet! The only way of knowing if the actual wall is wet (which usually it isn’t) is to do a calcium carbide test using samples taken from deep within the wall. So if these people aren’t drilling holes everywhere then they haven’t got a clue what they are doing. Check these peoples qualifications. When many cases go to court, these so called "surveyors" get absolutely torn apart by the real experts. So in conclusion, unless you are a very well trained and experienced surveyor stay well clear of this type of thing. Get an INDEPENDENT person to look at your problem on your behalf, and not someone from a damp proofing company! They should be a member of the Royal Institution of Chartered Surveyors. Also remember that it is unlikely you or your builder have any understanding about structural engineering - so that kitchen wall you wanted to knock through - don’t do it without getting professional advice! "
Damp Expert
Date Added: Saturday 18th July 2009
"Thank you for a clear and honest article on a difficult subject. "
Elias Cheriyan
Date Added: Friday 27th March 2009
"We have a room below ground level , one wall is very damp would it help the wall if we concreted over a small garden above it?"
p grimstone
Date Added: Monday 23rd February 2009
"i am renting a house and i have 2 young children and i am pregnant with another, my home has mould, wet patches, black mould and stains all over the insides of the outer walls, it took my landlord since December to send a builder out to me (it is now end of Feb) and the builder looked round and gave me dettol to clean it with even though i have been cleaning it every week with dettol since i moved into the house. i tried explaining this to the builder but he wouldn't listen and went. i don't know what else to do has anyone got any ideas. i would pay for a builder myself but i am a single parent and i am only receiving benefits. please email any idea to wreid1986@hotmail.co.uk thankyou "
samantha harrington
Date Added: Wednesday 18th February 2009
"Hi has anyone used the Holland Damp Proof system or the Schriver Systeem ,it is not a Chemical injection but clay bricks with porcelain tubes inserted into the walls where the damp course would be on a new build. Has anyone had these systems installed and if so did the system work? "
Peter Mills
Date Added: Monday 10th November 2008
"I had a surveyor diagnose rising damp using one of those meters. I then brought a builder friend round to remedy the problem, he laughed at the diagnosis made by the meter. In fact, the meter caused more of a problem by digging small holes into the wall which acted as centre points allowing the steam from my bathroom to condense more readily in the wall opposite in the hall!!"
Simon
Date Added: Tuesday 16th September 2008
"PLEASE PLEASE PLEASE be aware of the 'sharks' within the industry. I recently had a rising damp problem in my house and the difference in price between the different companies I received quotes from was SHOCKING. For recommended companies, check out the PCA (Property Care Association - its a website for qualified and vetted companies within the industry). I did and ended up using a company called Wise Property Care. I recommend them. It was nice to get a surveyor that was honest and trustworthy. Thank you also to websites such as 'what price' giving advice towards problems like this. Before having my rising damp problem, I didn't have a clue about what the issue was."
Andy Ferguson
Date Added: Sunday 10th August 2008
"Thank you for your advice. I had damp proofing a year ago and now I have white powder on the walls & the paint is flaking off. I asked the people to come back & they said its because of my back door letting draft in. Are they right or are the mineral salts on my walls rising damp? Also, I put some plastic down for other parts of my room and he said this was wrong but since I have done it the walls have dried out. "
Donna Brierley
Date Added: Saturday 7th June 2008
"The statement "appear to be a lot of companies offering a chemical spray treatment" is still true. Google it. "
Admin
Date Added: Saturday 7th June 2008
"u say a spray treatment? a rising damp treatment is to drill into the brick and inject the chemical ensuring it penetrates,totally different to what you are describing!"
dc swansea
Date Added: Friday 21st March 2008
"Thank you so much for this straight forward guide! Have had several people over rubbing their hands and tutting! Is there any way a competent DIY'er could treat the damp? Tips and advice would be most welcome."
Cordelia
Date Added: Friday 29th February 2008
"I'm wondering if you have ever heard of the american University prof who built four brick pillars in a ditch, using different but common mortars, and then filled the ditch with one foot of water and found after some years that no moisture had risen in any of the brickwork. Could this be true? I am thinking of buying an old house in N.Wales and wondering whether to have a damp course put in. It doesn"t at the moment seem to need one....."
brianmcadam@onetel.com
Date Added: Saturday 23rd February 2008
"dd that it isd important thst whom ever you choose has the full (normally product based) backing/guarantee - soveriegn chemical guarantee for example - good old fashioned injecting can\'t heart - also remember the person buying your house may gut it anyway??"
gc
Date Added: Wednesday 23rd January 2008
"A very honest and useful guide - hopefully will reduce the numbers of people ripped off by 'rising damp' prevention companies. It would be very useful if you went on to comment in more detail on the treatments offered by these companies - I also think that at least most of them are fairly useless, as are the 'guarantees' offered by most of these companies "
D Davenport
Date Added: Friday 4th January 2008
"Instead of a comment, I have a question, to which I'd be graetful for a response. I live in a first floor flat, which has damp along some external walls. I have read that it cannot be 'rising' because gravity would prevent any water rising this high. I believe the damp course on our building is old and perhaps faulty, but the damp has only set on in the past few months. I keep the place ventilated, and so it's not (I think) condensation. Could it be partly a drain problem (some is near where the down pipes run)? Any advice. Many thanks"
Doug
Date Added: Sunday 28th October 2007
"It is unlikely that low level dampness is actually endemic from the ground if; The vents to the subfloor arent blocked and are above ground level, gutters and rainwater goods are clear, any external render stops at the DPC, the external ground level doesnt appear to have been raised and the building was built after 1880. Retrofit chemical damp proof course injections dont work and should never be specified if the building was built after say 1900. Remember, the building hasnt always been damp, so ask yourseld what has changed? The real solution to the problem is to stop what is causing it and not cover it up! Key indicators of rising damp are; Sandy finish to the wall and salty to the touch, discolouration to a specific point then stops and mould isnt growing in the affected area (chlorides and nitrates from ground water inhibits the growth of mould). Also remember walls normally take 9 months to dry out. Remove plaster work to let the wall dry out, dub out in patch and set, then redecorate. If there is mould then pressure test CH, siphon test WM, check vents to whitegoods, extractor fans, make sure people dont dry clothes indoors, trickle ventilators are open. Then wash down in bactdet and halophen, 2 coats of biocheck and redecorate. Actually, get an independant CHARTERED Building Surveyor in to take a look and write a schedule of what work is required that you can then give it to a builder or whoever. A report will only cost about 200 pounds + VAT, which seems a lot but its a fraction of the money you could waste on chemical treatment that you dont need and redecorating for the problem to later return. Building pathology and science of defects is an expert field and its not something I recommend DIYers getting involved in myself. If the problem is developing or just began then the problem may be something far more sinister than rising damp eg, a loss from a watermain under the floor or broken drains! Hope this helps. "
A Building Surveyor