/ Home & Energy

Don’t be a drip! Watch out for dodgy damp advice

Damp companies that offer ‘free surveys’ may seem appealing, but our latest undercover investigation found several companies recommending unnecessary treatment that could cost hundreds of pounds.

Everyone loves a freebie, but if you’re tempted by the ‘free surveys’ on offer from damp-proofing companies, you may end up spending more than you need.

In our snapshot damp investigation, we invited damp-proofing companies to carry out an assessment of our properties’ damp problems. In two thirds of cases they recommended unnecessary or inappropriate treatment, or missed the problem completely. But does that mean you have to pay to get good advice?

All we needed was a plumber

In one case, our property had a leaky toilet – and any damp specialist should have instructed us to get this fixed before the room could even be assessed for other potential damp problems.

There was no evidence here of rising damp, and yet four of the eleven companies told us that we needed to install a chemical damp-proofing course in the walls and re-plaster the room – at a cost of up to £1,440!

That’s not to say all the companies were bad. We did see some good practice, with just over half of the companies that visited this property giving us helpful advice.

How to get good damp advice

Deciding whether to take your chances with a free survey, or shell out hard cash for independent advice is a toughie. Even though I’ve seen these results first-hand I know I’d be tempted to try my luck with the free option first – although I’d make sure to get at least three companies to come round and quote for the work.

Then, if there were inconsistencies in the work recommended or I had any inkling that the work might be unnecessary, I’d definitely consider getting an independent damp specialist round.

If you think you might need to call on a damp company, check our damp advice guide first for info on the different types of damp that can affect your home (if it’s just suffering from condensation you won’t need a specialist).

[This Conversation has been closed and is not open for commenting.]

peter jones says:
10 August 2013

I live in a block of 5 apartments with basements there is damp all the time in the basement I think I know the reason but its not totally up to me I have given my thoughts but would like a second opinion
thank you
P jones

Becky says:
12 August 2013

I’m looking for a bit of advice on the best solution for damp in a detached 20s house. We have signs of damp in several walls .. paint peeling/cracking on our ground floor, and high-med damp readings were present when surveyed (we bought in Oct last year).

We’ve had several contractors to look at the problem who’ve all suggested rising damp as the ground level outside is higher than the DPC. However, suggested solutions have varied and cost!

The builder I trusted the most (did a thorough report, walked us arround and explained problem) suggested stripping back to chest height, new DPC and replastering internal and external. Cost:£7k (its quite a large area)

But another builder said that a french drain would solve our problem (cost: £1k)

And another suggested debris in the wall cavity which needed removing.. but on investigation this didn’t turn out to be the case.

I keep thinking that in theory a french drain should work, but don’t know enough about this and without spending more on surveys etc we’re not sure what to do for the best!

Help please?!
Thank you!


When considering damp issues, it is important to firstly identify and remove the source of water. Sometimes (but not always) it may not be necessary to carry out more expensive works. My advice, which should be treated with caution as I have not seen your property, would be to improve drainage around the property first through measures such as as french drains. If this is insufficient then you can consider a tanking system.

And, as ever, the advice of an independent conservation architect or building surveyor should be sought.


Becky says:
12 August 2013

Hi Peter,

Thank you for your comments. I’m pleased to hear that the french drain could potentially resolve the problem but as you suggest I will seek out an independent specialist for more advice.

Many thanks,

Hi Becky,
I am not a builder but my initial thought is to find out if the high ground level is the only culprit.

Are you able to lower the external ground level yourselves to reveal the damp proof course and create a trench around the house? I think there should be at least 2 bricks showing below the dpc. Soil is easy to remove. If there is some kind of pathway, a circular stone cutting saw would cut it away. You probably need about a 6″ gap. Sounds like the outside of the house is rendered and I am no expert, but plastering over the external dpc doesn’t sound like a good idea to me. You could get a damp meter and monitor the damp for yourselves.

My feeling is that replastering might only solve the problem for a while and mask any real problem.

There are many reasons for damp. We had a damp problem caused by a cracked drain pipe in between the cavity wall.

Becky says:
12 August 2013


Thanks for your comment. Most of the ground around the external wall is concrete so we would need to get someone in to cut it away (too much for me!) but it sounds as though that may be an option. I’m going to get an independent assessor to come and take a look and advise further. Interesting to hear your experience of damp – a cracked pipe in between the cavity wall sounds like a hard spot!

Many thanks,

Jennifer says:
14 August 2013

Help please! I am in the process of purchasing a victorian conversion lower ground floor flat. After the bank survey came back indicating damp, we commissioned three of the big contractors to do damp surveys. All three have come back saying there is rising damp in all of the major walls and have quoted for repair work between £5k and £7k. Now the sellers are prepared to pay for this repair work as it was a condition of my offer, but I am really skeptical that any repair work will actually solve the problem. Surely damp is one of those things that recurs, especially in a lower ground floor flat? I am very close to walking away from this purchase and writing it off as experience (I am a first time buyer) and then looking for something more suitable at a higher level. Does anyone have any helpful advice or experience to offer?

Heritage House says:
14 August 2013

Jennifer – yours is a typical story we hear every day. You are quite right – none of that ‘work’ will cure the problem they have misdiagnosed. Dampness, especially in a lower ground floor flat is normally due to condensation – you may need to sort out some crumbly plaster and so on – that’s the symptom, not the cause. Condensation control is essential – if you search on google for ‘controlling humidity in damp houses’ you will see a number of pages which relate to sorting this out once and for all. Which? doesnt allow any links or commercial recommendations, which is a pity, because we can sort your problem out quickly and simply – but look for our name, and have a look at some of the other posts from John Durie and Peter Drummond further up the pages here – they are both very experienced people – one working for Scottish Heritage – and know their stuff – just remember – there is effectively no such thing as rising damp – every single damp issue that any of us have ever seen can be easily resolved without recourse to injecting and chemical plastering to seal moisture into walls. Remember also that the chemicals the damp industry uses are VERY toxic – and we deal frequently now with people who are sensitised to such chemistry – I’m trying to get more information on this as I get frequent complaints from people who have breathing problems after ‘damp’ works have been done. Hope this helps – remember – its all about moisture in the air – cure that, and the rest follows on…. Pete

I make no comment on the cause and cure of any damp, but you may like to consider other aspects of this possible purchase. As a first time buyer decades ago I was in a similar position except that it was for a ground floor flat and the surveyor noticed problems with the roof. I then recalled while in the flat I had seen a a “residents association” letter and thought “oh, that’s nice”. I quickly realised that it wasn’t nice, since the residents were having trouble getting the management company or owners to actually do the necessary repairs. I didn’t buy.

My preference in a flat is to ensure that the building etc is owned by the residents, so at least they are in charge of their own destiny, for better or worse.


This sounds like a complex situation; there could be a number of causes working together to create problems including some residual rising dampness, condensation, type of plaster finishes, and so on. My advice would be to get in a qualified building surveyor or conservation architect at an early stage.

Jennifer says:
14 August 2013

Thanks for your advice. I have decided not to go ahead with this purchase.

Paul Eglon says:
18 August 2013

I live in a terraced house built 1882 with solid brick walls – no cavity. I’ve been here for 12 years and the place was a state when I moved in. There was a lot of loose plaster and some rotten wood joists. Following damp survey I had a damp course injected and walls plastered up to a metre or so-from floor level. The sub floor is clay/soil and there is said to be a high water table so there are puddles when it rains. I was worried about this as there was sometimes a smell emanating from the floor. However, a couple of years ago I put hatches in floor and cleared out mounds of rubbish and put in new plastic air bricks. This has made a difference and the smell is no more. My main problem is the loadbearing wall between downstairs front and back room. (This is partly knocked through with doors added a couple of years ago).The damp injection and replastering seemed to have worked generally around the house- of course it may not have required the damp injection in the first place. Anyway, there are what appears to be salts coming out of the plaster on the said loadbearing wall. This didn’t seem to happen until a couple of years after original injection and plastering. I’ve had the damp company who did the original job out 3 times since the problem occurred. The first time they reinjected and replastered and the salts seemed to move to another area of the same wall. The company replastered again. It reappeared and the company replastered again and problem has reoccurred. I don’t really want to get the company out again-I know the guy personally who owns company and really it probably isn’t their responsibility. An independent plasterer did the plastering. I do not want to get another damp company out – they’ll probably just reinject and replaster anyway . I purchased jeff howell’s book – the rising damp myth – some time ago and am aware of the shortcomings, to put it politely, of many damp proofing companies. I did have an independent surveyor, who came recommended, out a couple of years ago. He was a general surveyor not a damp specialist. He was a nice bloke who said that such problems can be a long journey. He advised repair to lead lined guttering which we did. He also advised knocking some bricks out of the said dividing wall below floor level. He advised that the drain that runs from the down comer from front guttering be checked. He felt that this may have been causing the water underfloor when it rained, as opposed to high water table theory. I haven’t had the drain checked but have re routed the down comer to run straight out to street drain. I’ve just checked subfloor and there isn’t any lying water although the soil/clay feels moist. There has been rain during the last few days. It may be that the re routing of down comer has had desired effect. Another issue is apparent damp on wall to the left of fireplace nearest to outside wall in said room to front of house. Wallpaper feels damp to touch at up to 30cm above skirting (9 inch). This is an open fire not used for some time. I noticed damper was closed and have opened it.
I would greatly appreciate any advice on these matters which have me demented. By the way there are no pipes near to where the problem is occurring so no water leaks to be repaired.
Regards, Paul Eglon
Ps I can attach photos if required


This sounds like a complex situation which is unlikely to be capable of diagnosis by way of anything other that exhaustive site investigation.

Salts will typically come to the surface as a result of drying of the substrate; this might be from the original wetting/plastering (although that seems doubtful) or subsequent episodes. That the solum (subfloor) is moist suggests that the latter might be the case. Can I ask what your local soil conditions are like (heavy clay, for example) and whether there are French Drains or similar around the house?

I would note in passing that only renovating (or certain lime) plasters should used where there is residual dampness and a risk of salt precipitation inasmuch as modern gypsum-based coatings such as Thistle and Carlite do not tolerate such problems well. In all fairness, most damproofing contractors are aware of this and tend to use Limelite or similar products.

On a different note, do not entirely rule out condensation. I am not as wed to the idea as others in my profession, but inspected a church just last week where poor ventilation in conjunction with a Sunday-morning-only heating regime had led to pretty ghastly problems.

Heritage House says:
19 August 2013

It might be worth noting that Limelite is as bad as any of the other products – it is non-porous and made with cement – I spend as much time hacking it off as I do removing cement render and gypsum. Do NOT USE LIMELITE!!!!!!
There really isnt any substitute for lime plaster I’m afraid!

All the best


Paul Eglon says:
18 August 2013

Thanks for your reply, Peter.
I’m not aware of local soil conditions but can try to find out. I’m sure there are no French drains. Also, I’m sure the original plasterer and plasterer who did subsequent ‘repair work’ didn’t use lime based plaster. Sand and cement followed by pink gypsum finish plaster were used.
The two rooms referred to are cold and freezing in winter. Even when hot outside, the two rooms, especially the front room where the tide mark is on the fire breast wall, are cool.
I’m determined to have this problem rectified hopefully for this winter.
If you are unable to offer remedies without actual inspection are you able to recommend any reputable person who could carry out an inspection in the Tyne and Wear area. Which Local lists damp companies but these seem to be the type that offer injection ‘remedies’ – I wouldn’t entertaint these.
Regards, Paul


The important things is always to try and adress the source of a problem,r ather than the symptoms.

So, for example, the pink or orange topcoat you see will be a gypsum based Carlite or Thistle which is susceptible to salt/dampness however if you can find and remove the source of dampness then there is not necessarily a reason to replaster the house yet again.

As your surveyor pointed out, this can be a slow process but it certainly beats paying for damp treatment which you might not always need.

This in turn takes me to your comment about a damp solum. If you’ve fixed the gutters, and there are no pipes (or drains) which might be leaking in the vicintiy, then I would tend to think about ground water and condensation.

Soil conditions – does your garden become boggy quickly in rain? Do you have a thin dressing of soil over (say) a heavy clay? Are groundwater levels high, inasmuch as water might then sit within your underbuilding and cause problems? If so then consider fitting surface water drains around the house. They have to be constructed in such a wayt that they do not act as reservoirs.

Condensation – cold walls, central heating, and sometimes poor ventilation together make for a problems. Gas fires, cooking, and (dare I say it) breathing all put surprisingly large amounts of moisture into the house. If the walls are warm then it’s not a problem – the condensation will occur somewhere out towards the vacity – but if (say) it’s a warm air system only on for a couple of hours a day then the walls will rarely heat up.

But on a slightly different note, you mention the chimney breast wall. I’m not sure if you still use the chimney – apologies if I missed this. Whether it’s in use or not then check the condition of the chimney stack, making sure that all mortar joints are tight and that the flaunching around the pots is shedding water away. If it’s not in use, then make sure it has a ventilated cap at the head (the old clay “elephant’s foot”) and a fresh air inlet/vent at the base. They can be a surprising source of dampness.

Heritage House says:
19 August 2013

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Adam Gallucci says:
19 August 2013

I’m about to move into a property, my RICS surveyor indicated high damp readings in most exterior facing walls. Some of the plaster seems to be crumbling in patches, under a bay window in the front room for example.

It is 1900 cottage with ‘no obvious DPC’ according to his report.

I have a quote for £990 to hack out the plaster, chemical injection DPC, re-plaster – HOWEVER: the property has never had central heating, has poor insulation and has been heated with mains Gas Fires in all rooms.

1) Could this ‘gas heating’ be the cause of dampness? – in which case:
2) Should I just sand down the plaster, install CH and see what happens? or
3) look at DPC even though I’m reading a lot about cowboys and ‘Rising Damp’ being a myth…?

Help – I’m confused. Thanks!


You are right to be wary; in my personal experience the more typical causes of dampness are penetrating moisture (for example through defective external masonry joints or render coatings), leaks (whether from rainwater goods or old pipes), or condensation. If the damp is more than the very base of the wall then these would be the areas I would investigate.

As for gas fires, yes they can put quite a bit of moisture into the building depending upon type and flueing arrangements. My preference is for a “proper” central heating system in almost all cases, running at a level wiich heats up the walls and limits the scope for condensation. That and good ventilation.

On a final note, get all your gas installation checked by a qualified gas engineer as soon as possible. It can surprise you what you find in old houses.

Heritage House says:
19 August 2013


Comments below:

I’m about to move into a property, my RICS surveyor indicated high damp readings in most exterior facing walls. Some of the plaster seems to be crumbling in patches, under a bay window in the front room for example.#

Damp readings are from a pin meter that doesnt measure damp – it measures conductivity. If you google ‘damp in old houses’ you’ll see a website that covers these issues. Most damp is from condensation – it certainly doesnt rise. Peter Drummond has covered most points very well,

Remember that temperature of walls is critical – condensation occurs at the coldest point – down the bottom and in exposed bits of walls like bay windows – hence crumbling plaster.

It is 1900 cottage with ‘no obvious DPC’ according to his report.

It doesnt need a dpc – it needs to breathe – remove the modern materials like cement and gypsum plaster which are stopping the breathing and it will be warm and dry!

I have a quote for £990 to hack out the plaster, chemical injection DPC, re-plaster

No No No – when will people wake up after their house has been re-plastered with impervious materials for the tenth time – get it breathing! Dont waste your money – all it will do is swell the damp industry pockets and give you a cold home.

I’m reading a lot about cowboys and ‘Rising Damp’ being a myth…?

They mostly are, and it is!

Help – I’m confused. Thanks!

Hopefully not now – think breathability and ventilation – remove humidity. On the front page of my website is a little humidity hygrometer – on amazon for about £25 – buy one, and measure the humidity in your home. Youll be amazed. It needs to be under 55% – and usually in a damp house isn’t. If its high, you’ll need to have a look at the RHL website – warm air dehumidifying fans which take out moisture at source – and ten percent of the cost of the damp cowboys.

Hope this helps direct your research a bit!

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Adam Gallucci says:
19 August 2013

A massive Thank You ‘Heritage House’ and also to Peter Drummond for cutting through what is a very concerning area for consumers.

Heritage House says:
19 August 2013

My pleasure – hopefully one day we will eliminate the damp cowboys completely and educate people that with care, an old house can be warm and dry. Condensation is our biggest issue, closely followed by inappropriate materials that don’t allow the house to breathe – if all the folks who enquire on this forum were to address these two issues, they’d almost certainly have dry houses, and certainly wouldn’t need any ‘damp treatments’.. Good luck – and thanks for the compliments!


my neighbours condense pipe is dripping constantly and causing a green sludge on the outside wall of their house, it is only about 4inches away from my property and worried that this may cause damage to my property too. Unfortunately my neighbour is not a person who I would wish to discuss this matter with due to the fact last year he knocked down my garden wall, we even had proof of our ownership but sadly was told this would have to be taken up with a solicitor, we are in our 70’s and not in the best of health, we have got absolutely nowhere. My wall is still demolished. Can anyone help as we cannot afford solicitors?

Colin says:
27 August 2013

We had damp surveys carried out by two of the big five companies prior to buying our home. Both identified issues with “rising damp” and recommended injection and replastering. Both areas were in the rear where we plan to build an extension in time so we bought the property knowing we’d have to live with it for the foreseeable future.

We have now completed renovating the front of the house – where no damp was identified – and there now appears to be damp affecting the chimney breasts in both the front room and dining room on the ground floor. The layout is traditional victorian semi – two rooms then kitchen out back.

We removed the original marble surrounds and fitted reclaimed cast iron inserts. Now there’s a very visible damp patch in the new gypsum skim coat plaster just above the skirting board on the right hand side of one fireplaces. The mist coat we applied isn’t drying in this area. There is also “rust” coloured discolouration on the marble close to this patch and in a big block on the hearth next to the insert in bottom right hand corner. There are also much smaller areas of discolouration on other parts of the surround and similar ones on the dining room surround. These marks weren’t there after we had them stripped and cleaned.

The fireplaces were wrapped for 5 weeks to protect them from plastering and painting. The builder said it’s due to evaporation and condensation and there being no chimney. He then said the plaster hadn’t dried out properly. I find these explanations hard to believe.

The chimney is open into the attic – the chimney stack was removed by the previous owner. The front room fireplace was boarded up with a gas fire and the dining room left open and decorative with vents.

I’ve looked under the boards and the brickwork does feel damp but this only appears to be up to floor level around the front of the chimney and hearth and in the other walls is only up to the ground level outside. There doesn’t appear to be a dpc. There are two air bricks in each room and air can pass they’ll length. The floorboards were insulated about 6 weeks ago in both rooms. There were no leaks in the mains feed that runs down the middle of the rooms and there are no other pipes in this area.

The exterior wall that crosses both chimneys is rendered with what I’m guessing is cement and painted. The public sewer runs down the side of the house near this wall but our side entry and that of next door is concreted over. There have been issues with settlement in the past.

The fireplace installer has said he levelled the hearth with postcrete with waterproofer before fitting as a “precaution” as he “suspected something”.

What action is needed? Do we need to inject the hearth and “pillars” on either side of the fireplace? Do we need to remove the fireplaces completely? Will hacking off the external render allow the hearth to breathe? Do we need more air bricks? Could the sewer be cracked?

After reading about chemical injection I’m concerned it’s unproven and could be toxic. I’ve also lost faith in the industry as this wasn’t picked up earlier. Getting a big firm in comes with guarantees but we can’t afford any unnecessary work both in terms of cost or time.

I know it’s difficult without a survey but after 4 months with four of us (including two toddlers) living in one room at the in-laws this is tipping us over. We were just about to move in. This couldn’t have happened at a worse time! Any advice is very gratefully received!

Heritage House says:
28 August 2013

‘Damp’ on fireplaces is almost certainly salts – very little to do with damp, and mostly to do with soot reacting with water in the air and producing an acid environment which attacks the lime in the mortar, producing mainly calcium and magnesium sulphates and nitrates. These travel down the stack and appear as brown stains and fluffy white deposits. Ideally all parts of the stack need to be cleaned of modern plasters, and thoroughly swept, then lined with stainless liners. The stack needs to breathe – good airflow – so eventually the salts migrate to the surface, are brushed off regularly, and are thus a finite resource. NEVER replaster with modern materials – cement, tanking plasters, gypsum etc as recommended by the damp companies. Your house needs to be dry though – properly dry…

Rising damp doesnt exist – In all the years I’ve done this sort of consulting work I’ve never seen it. Injecting doesnt work and never has – it is a giant con. I’ve seen houses with four injection damp courses above each other – still with peeling plaster and damp problems – all because impervious tanking and gypsum plasters have trapped condensation. Injecting damages brickwork, and traps moisture into it – causing major problems in the long term. We are doing research at Kenilworth Castle which proves just how destructive injection damp proofing actually is – very serious.

First thing – buy a thermo hygrometer and check humidity levels in your house – they must not be over 55%. At any time, in any temperature. If they are, its likely you will have condensation problems which are the real reason for any dampness.

Remove humidity with the rhl condensation fans – they are on our website as a link, and you need to buy a thermo hygrometer first – about £25 on amazon – again, our site, if you can find it , has links to these. Spend no money until you understand where ‘damp’ is coming from.

I’ve just surveyed a house that three of the so called top damp companies – all members of their treasured association – have quoted between £15,000 and £30,000 to ‘damp proof’. It was bone dry. The only thing needed was a bit of ventilation, and removal of several layers of wallpaper that were trapping a bit of condensation.

Don’t give up – the solutions are simple, inexpensive, and NEVER involve damp companies and chemicals! Focus on condensation, and the moisture YOU produce in your house – it will surprise you just how much..!! It all has to go somewhere… and it does – into the fabric, and the coldest bit of it…

All the best


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Robusto says:
17 September 2013

Have you actually got any proper references to support your claim that rising damp doesn’t exist? I can find lots of peer reviewed academic papers and publications from the likes of BRE, Fraunhofer, etc that support the fact that it DOES exist – which isn’t particularly surprising as it is fully predicted by the laws of physics. Obviously I am aware of Jeff Howell’s self published Rising Damp Myth book, but that is full of school boy errors and wouldn’t stand a chance if subjected to peer review. I’m talking about real evidence rather than conjecture put forward on websites published by so-called “Heritage Experts” who seem to think that calcium hydroxide is the solution to all damp-related problems but isn’t a chemical or in any way hazardous. How about a real debate based on proper evidence. All I am asking is that next time you make a statement that completely contradicts the laws of physics or slags off a whole industry you at least have the decency to properly reference the source of your claim.

London Conservation says:
17 September 2013

Robusto . In short. Yes.

a few WELL respected sources of rising damp research below;

Chairman of RICS states in article Rising Damp does not exist. It is a breach of Which terms to pot a link – so search for this in google – “Rising damp is a myth, says former RICS chief”

Mike Parrett – tested hundreds of houses diagnosed with rising damp in the 80′s and did not find a single example – there was a video about it, its probably on youtube called something like “rising damp – no such thing”. Mike is a horrendously over qualified building scientist ……EDIT found the vuideo is called ” Renovation Rising Damp ? No such thing”

BRE (Building research establishment) – Publish updated guidance notes on “rising damp” in their BRE digest. They make continued reference to PROPERLY determining rising damp by taking moisture tests from carbide tests / lab tests etc etc. The BRE digest 245 has also been revised, and makes referance to rising damp in CAVITY WALLS.

Jeff Howell – Southbank university – left bricks in water for 3 years and couldnt replicate rising damp under lab conditions

English Heritage – ” Surveying your Property ” makes mention of rising damp and condems injected and non water permable renders etc.

Tim Hutton – Building conservation – Rising damp – a very good overview of what rising damp is and how it is so commonly misdiagnosed.

All of the above available on the web ! Read up.


Oh make no mistake, Roberto, I believe rising damp exists. However I have never seen it extend more than 300mm above external ground level – and only then in exceptionally wet conditions.

The first objective should not be to address the symptoms with an injected dpc of dubious worth or a membrane system, but rather to look at the source of the moisture and control it through alternative means – for example improving surface water drainage around the building, cutting back hard surfaces around the base of the walls, and improving subfloor ventilation. Only if these proportionate measures do not work do you start to consider other solutions.

What I also see is penetrating dampness, usually from defective masonrywork, and to a lesser extent internal condensation both misdiagnosed as “rising” dampness. Owners are then sold expensive “solutions” which may have little impact on the underlying problem.

I do not believe rising damp does not exist in old buildings – the physics of capillary action were around then as they are now. However, buildings were constructed and finished to deal with the moisture that entered the structure – stone or suspended floors, permeable internal and external wall finishes, and ventilation through gaps and flues for example all allowed the moisture to escape and kept it controlled.
An interesting document is found in the attached link:
I’m sure the experts will have comments to make on this.
What a pity this has been such a divisive conversation from the start. Can the facts be spelled out authoritatively and agreed upon so proposed solutions can be soundly based? Or is that an impossibility?

Robusto says:
17 September 2013

I understand that there are people who say that rising damp doesn’t exist, but there doesn’t appear to be much properly reviewed literature out there to support the claim. Just because someone who used to work for the BBC (David Icke) claims that the world is comtrolled by shape-shifting lizards doesn’t mean it is true. The same is true of claims made by former employees of RICS or any other organisation.

I am aware of the sources that you quoted, but apart from BRE and English Heritage they are really just people’s opinions.

I am well aware that rising damp is often misdiagnosed. However there is a big difference between saying that something is misdiagnosed and saying that it doesn’t exist.

Heritage House says:
17 September 2013

The opposite argument also exists – there is little or no research or evidence which supports rising damp.

What we DO know is that an entire industry exists on the basis of misdiagnosis – every case of so called rising damp I have ever seen could be simply sorted without resort to unproven and destructive drilling which shatters brickwork, tanking of walls, and soaking of peoples houses with toxic chemicals.

Robusto says:
17 September 2013


I have some sympathy with what you say – although I have to say that if I had rising damp 300mm up my walls I would probably want to do something to get rid of it. Just because it doesn’t typically rise higher than this doesn’t mean it’s not a problem.

Ralph Burkinshaw is certainly of the opinion that most rising damp is really caused by what he calls “low level penetrating damp” rather than ground moisture. In these situations the best thing to do is remove hard surfaces around the affected walls. However this is not always economic (e.g. Expensive driveways) and is not really much use when the rising damp is affecting party walls etc… In such situations I really can’t see what is wrong with using a decent quality BBA approved chemical damp proof course – although I do have a problem with the amount of replastering that is usually recommended with such systems.

Robusto says:
17 September 2013

Heritage House,

If you do a quick search for Rising Damp on Google Scholar you will find literally hundreds of peer reviewed papers which refer to the problem of rising damp – so if it’s a conspiracy it’s an incredibly well orchestrated one on a worldwide scale. The fact that there are numerous Victorian references to rising damp also suggest that it is not something that was invented by the damp-proofing industry in the late 20th century.

I agree that there is much misdiagnosis of rising damp, but to say that it doesn’t exist at all does nothing for your credibility which is a shame as some of the other points you have made about buildings breathing etc are very valid.

Heritage House says:
18 September 2013


The whole capillary argument is great in theory – it doesnt work in substrates where pore size varies greatly – real world.

I dont disagree that it is theoretically possible – it’s never been proven to happen in practise – except to a point where it is just above ground level and evaporating nicely.

The problem we have is a huge industry which relies on selling many millions of pounds worth of (some are based on Agent Orange) chemicals for damp proofing, which promotes rising damp as a huge problem. Their surveyors are trained to sell ‘treatment’ based on misdiagnosis. Take out the chemical industry, and everyone would find the alternative – which as you say – is breathability.

How can we continue to push this silly practise when the Dutch dont even have damp courses.? I’m about to put up some examples on our website of old and new buildings sitting on swamps, which are dry as a bone, and have no damp course. One of our clients lives there, and laughs hysterically at the entire english damp proofing industry – it is ridiculed in Holland. She tells me that Dutch building control banned damp courses after they had instances of buildings rotating on them – I have since seen this in surveys I’ve done over here. I teach at college – and work with a highly placed Dutch architect who has extensive experience in this area – she echoes my sentiments.

At the moment, the only way we can rid the country of the damp industry is to educate people. This is working – my volume of web hits, phone calls and emails is rising exponentially. Together with that, I get more and more people who say they have researched damp, and realise they are being conned – and want to look at holistic solutions. They say that imitation is the finest form of flattery – I now have damp proofing companies and organisations copying my website and photos off it…. Notwithstanding the big legal fees they will be getting, it does go to show that the damp industry now realises it is a total fraud, and is running for cover as fast as it can!


Robusto says:
18 September 2013


Once again you make some intersting points, but then go and ruin it by adding the fabrication about Agent Orange. Why on earth would anyone make a damp-proofing product based on Agent Orange? It wouldn’t have any effect in protecting against dampness, it would be incredibly toxic, and it would be impossible to make as most of the ingredients of Agent Orange have been banned. Which product are you referring to? And what is the source of your information? Or did you just make it up?

I’d also be interested in the source of your information about the Dutch banning damp-proof courses. The “ban” doesn’t seem to be having much effect as most Dutch online builders merchants seem to have loads of them in stock e.g. http://www.bouwshoponline.nl/merk/topprotect.html


Your comment neatly sums up my judgement of heritagehouse, both the “good aspects” and the “could-be-improved aspects”.

I’ve been following this conversation since the beginning (I wrote the first posting!). I have been interested to watch the various parties make various points, with varying degrees or validity and emphasis, with varying degrees of light heat and fog.

It is clear to me that damp is complex and that every party claiming there is One True Problem/Solution is making unjustified claims.

This discussion has gone the way of many “usenet discussions”[1] over the past 30 years. In my opinion Which? should be extremely careful that hosting such discussions does not dilute Which?’s value proposition: that of impartial advice for consumers which cannot easily be obtained by other means. IMNSHO, that is extremely important for Which?’s continued survival.

[1]for it has many characteristics in common with usenet

Tracy says:
4 September 2013

After some advice please.

I live in a 200 + year old mid terraced cottage. In the past we have had very minor issues with a couple of small damp patches. This week our internal wall was dripping wet. Overnight it dried to just feeling damp and the palster has gone all chalky.

All the pipes have been checked and we can find no leaks anywhere. Husband lifted the skirting boards and wooden flloring and the floor underneath is damp. I think basically there are no real foundations and it is asphalt laid on soil.

About 18 months ago our next door neighbour adjacent to the wall where we are having the most severe problems had her house tanked. is it possible that this has transferred the issue from her property to mine or am I talking rubbish?

Currently researching companies to come and have a look at it but not really got a clue where to start.


John Durie says:
16 September 2013

It may be that your neighbour, by having her property ‘tanked’ has encouraged the ground to become saturated where it was previously able to deal with the ground water. Do not follow her lead – waterproofing will be disastrous to your property and will create more problems. It must be able to breathe. Check for underground drainage problems, ensure rainwater gutters and gulleys are clear and that there is sufficient sub-floor ventilation. Consider installing a French drain to reduce the amount of ground water close to the building if you cannot reduce ground levels.

Thanks for your response

There is no standing water outside, it drains pretty well all,year around and there are no issues with gutters etc.

As for sub floor ventilation I am not sure what you mean here. The house has no foundations due to its age and is laid on soil and asphalt basically.

We have just had a survey done and they suggested it is rising damp due to failure of the damp course and walls need re plastering. I do know it had a damp course at one time but it must be well over twenty years ago and the installers weren’t that great as it’s a single thickness wall and they managed to go through into next door’s lounge!

John Durie says:
17 September 2013

Hmmm. Without seeing it, it is difficult to give you advice. The clear advice I would give is DO NOT approach a PCA surveyor as it is clear, from my experience and that of colleagues, that their main aim is to sell chemicals – not to find a solution to your buildings problems. Unless they are qualified or experienced in building pathology, building surveying, architecture or construction and have in-depth knowledge of traditional construction, don’t let them any where near your property. Call SPAB in London – or search their site for area contacts and ask them to recommend a local company who they trust.
Who did the survey? Did they explain how replastering would deal with a saturated structure? Did they look outside? Check ground levels? Suggest a drain inspection? Replastering would be the LAST thing I would consider until I found the cause. I’m surprised they didn’t suggest a really thick wallpaper would help!

Heritage House says:
18 September 2013

Tracy – your so called surveyor is qualified to what level?

They are talking complete rubbish.

Have a look at the humidity levels in the building first – get a digital thermo hygrometer for about £25 and record them – any higher than 50 to 55% and you have a problem – that is the real reason for the damp. Buy a little piece of kit that informs you so that you know how much moisture there is in the building – THEN, you can make informed decisions about ventilating, lowering humidity, and living in a dry house!

[This comment has been edited for breaking our T&Cs. “Do not promote your own or your employer’s business, or otherwise include any advertising or promotional material”]

Hi Heritage House, we have had to edit a number of comments for breaking our T&Cs. “Do not promote your own or your employer’s business, or otherwise include any advertising or promotional material” This includes asking people to Google the name of your business. https://conversation.which.co.uk/terms-conditions/

Thanks very much.

Well to be honest all you have done really is to confuse me even more now! Reading through the site all you seem to do is argue and disagree between yourselves so how the average man on the street is supposed to get anywhere is beyond me!

Yes this is confusing for the man in the street such as myself.

Nonetheless that is mainly because dampness is an intrinsically difficult problem in that there are many possible causes and many possible solutions. That is a principal reason why it is possible for less-than-perfectly reputable organisations to operate in this area.

The least bad approach is the same as it has always been for any topic in which you are not an expert.
(1) develop a cursory understanding of the topic, including the terminology used
(2) learn what to look for in your own property so that you can start to assess what might be relevant and irrelevant
(3) learn the key important questions which need to be answered
(4) assess individual companies/people in the light of what you have learned
Then you can ensure that individuals/companies realise they can’t boondoggle you.

And exactly the same is true w.r.t. getting a car fixed, or a computer system implemented, choosing on a course of medical treatment, etc etc.

No, it isn’t easy and does take time. If it was easy then there wouldn’t be a need for a discussion/
The easier alternative is to tradeoff reducing your time by spending more money.


We have been told the ‘damp’ patches on the chimney breast in 2 of our bedrooms are due to salts. The advice was to either regularly re-decorate the patches to cover them up, or to strip the plaster back and line the walls with some special waterproof liner and replaster. We were quoted a price of approx £1800 per room to do this work and told it would totally solve the problem.

I have seen the recent post which gives advice on how to deal with salts but am not clear how this fits in with what we’ve been told. The marks on the wall are prominent and unsightly and we are keen to get rid of them, if possible. What is the best solution?

Many thanks for any help with this.

John Durie says:
16 September 2013

I need more information before commenting. Chimneys indicate an old house. Are the chimneys used, blocked or vented? Is it vented at roof level, is the haunching intact, what condition is the external wall?
In any case – please do not re-plaster with a waterproof plaster or liner as this will mask the dampness and transfer it elsewhere.


Yes the house is approx 150years old. The chimney in question is used for a wood burner and has been lined. The roof has been vented and the chimney stack re pointed and re painted, the flashings have been replaced. The external wall is fine with no problems. Not sure what haunching is!

Any advice most welcome, the patches are becoming more visible with the damp weather.

Cheers mils


I agree with John; there could be a number of different causes. As a starting point I’d take a look at the chimneys and whether either penetrating dampness or condensation might be the source of the problem. Incidentally, haunching is the cement fillet around either the base of the stack (unusually) or around the pots/cans.




If the flue is dry then salts should not appear, although it may be the case that drying-out from an older leak could lead to damage. I think you need to try and find out where damp could be getting in.

You say that the chimney was lined. Was the right kind of liner used?

First you need to work out if the dampness is really being caused by salts. In chimney breasts it’s usually the prime suspect (salts accumulate in chimney structures due to decades of burning of sulphurous coal), however there can be other causes such as rain penetration through faulty flashings etc…

Assuming that the damp patches are actually caused by salts then you have a number of options:

1) Prime the wall with an alkyd stain blocking primer before painting. This is basically a varnish-like primer that can often stop salt-related stains coming through to subsequent paint layers. This will not always work, but it’s probably worth a try as it is so much cheaper than the other options that it is probably worth a go even if the chance of success is probably only 50%.

2) Hack plaster off and apply two coats of tanking slurry followed by plaster. This is very effective, but tends to be expensive as it takes several days to complete even though the area being treated is small – (day 1 hack off and apply first coat of tanking, day 2 apply 2nd coat of tanking, day 3 apply backing plaster, day 4 apply skim coat). It is possible to reduce the number of days required by using a single coat high-build tanking slurry which will probably make the cost a little cheaper.

3) Hack off plaster and apply a meshed plaster membrane. Backing plaster and skim can be applied to this. Alternatively plasterboard can be attached using plaster dabs.

Years ago, when our roof was being extended over an extension, rainwater got onto the ceiling plasterboard and stained the underside. We were told it would always show through any paint finish. We used aluminium primer and then conventional emulsion. No stain ever appeared. It might work on your chimney breast.

Nicola says:
16 September 2013

I need some advice about how to find an independent damp surveyor.
We have just moved into a terraced property. We have found damp patches on the walls. We have had 3 quotes from damp proofing contractors and the advice has been conflicting. We were told by one that all the walls were damp and would need to be treated, but that only the skirting boards would need to be removed and the treatment could be injected. The other two contractors suggested plaster would need to be removed up to a meter in height, but they disagreed as to which walls would need to be treated. We would like to arrange an independent survey but are struggling to find one in our area. We live in Liverpool. We looked on the PCA website and found one on Manchester but they have been unable to offer us a date for a survey at this time. Is there any other way we can find a reliable and independent surveyor?
Any advice appreciated.

John Durie says:
16 September 2013

Typical conflicting advice because it’s all bunkum!!! What type (age) of property do you live in? Read some of the posts further up this page and you will see the general advice that is being given by real independent surveyors, experts and highly respected conservation architects. Ground levels outside, leaking rainwater pipes, cement mortar or render, lack of ventilation etc. An independent surveyor is not necessarily a member of the PCA. None of which includes injecting chemicals.

[This comment has been edited for breaking our T&Cs. “Do not promote your own or your employer’s business, or otherwise include any advertising or promotional material”]


It sounds to me like you need independent advice. My advice would be to contact an experienced building surveyor (the RICS would be a good starting point) or conservation architect (try the AABC Register or the RIBA).



Deciding which sections of plaster will need replacing as part of a rising damp treatment is often a matter of judgement, so contractors and surveyors will often give differing opinions. It is impossible to accurately assess degree of salt damage in the plaster without destructive and expensive lab testing. Furthermore, the acceptable level of salt contamination will depend on a number of factors such as the type of plaster, the period of guarantee required, and the acceptability to the homeowner of any disruption in the future if replastering becomes necessary at a later date.

Many contractors prefer to replaster all of the sections of wall that they are treating. However, the British Standard on rising damp treatment (BS6576) gives the following option:

“Where the plaster appears to be in sound condition, the extent of plaster to be removed may be minimised by delaying any decision to replaster until the drying period is complete.”

Obviously the phrase “appears to be in sound condition” is open to interpretation. However, unless you are in a great hurry to get the rooms decorated I would suggest injecting a damp-proof course and waiting 6 to 12 months for the walls to start to dry out before deciding which sections of plaster need replacing.

I’ll stay out of the argument about what constitutes a proper surveyor except to say that the good ones cost a lot more than it would cost to get a contractor to inject a few tubes of damp proofing cream.


It has been pointed out many times before on this site that an ‘Independent Surveyor’ refers to somebody that is properly qualified in surveying and has no connection whatsoever with any trade organisation. The Royal Institute of Chartered Surveyors have many members who are qualified in resolving building problems, as does the CIOB (Chartered Institute of Building). People should be very circumspect about people calling themselves surveyors when they have no training in surveying or recognized qualifications.

[This comment has been edited for breaking our guidelines. Thanks, mods.]

Agreed, but I’d point out that a good conservation (not necessarily general practice) architect should also be considered.

Nicola says:
17 September 2013

Thanks for the advice.
As a lay person it is difficult to get a grasp of all the different qualifications/organisations. If someone is registered as an independent surveyor with the PCA am I likely to get a reliable survey completed or am I better to contact someone registered with RICS/AABC?
I have been in contact with someone registered with the PCA as an independent surveyor who is able to complete the survey in my area for £250.

It is difficult to get a grasp of the technology and organisations, isn’t it. I’m afraid I don’t have a neat answer, but consider

(1) “following the money” to find out where someone’s interests lie (i.e. who pays their wages), and

(2) find out what the various professional qualifications mean and what organisation awarded them, and

(3) if they are unprofessional, what are they in a position to lose – either financially or reputation

The latter is particularly relevant w.r.t. trade organisations (which are often there to protect their members more than to marginalise cowboys) and/or legally recognised organisations (which may require professional indemnity insurance).

We live in a 1950s home which was concrete construction until about ten years ago when we had all the downstairs walls rebuilt with brick and silver backed foam insulation. Only downstairs walls because its a Cornish unit where the roof goes half way down the house. We have black mould on the outside walls in our one of our front bedrooms and always have, only this room is affected not the other bedroom on the same side of the house and the rebuild has made no difference. We have over the years treated with damp proof paint but still it comes back. This room is above the kitchen but apart from this there is no difference to any other room, in fact the back bedroom is closer to the bathroom. This problem only worsens in the winter. Any body got any advise as to why its only this room if its our lifestyle like cooking, showering and so on why would this not affect the other rooms.

Have you tried improving the ventilation in the affected room?

John Durie says:
17 September 2013

I agree with Peter. The assumption that it is likely to be caused by human habitation. Cold outside, production of moisture inside, low air changes, vapour condensing against cold (external) walls, condensation causing black mould. Try increasing ventilation, move any furniture from external walls and allow air to circulate, weak bleach solution to clean mould from the wall – taking care with whatever wall-covering you have obviously. This stands true for modern and traditional construction.

[This comment has been edited for breaking our T&Cs. “Do not promote your own or your employer’s business, or otherwise include any advertising or promotional material”]

Ironically, the PCA make this comment on one of their technical web pages:

“What many fail to realise is that to manage atmospheric moisture effectively, the relationship between four factors – water production, ventilation, insulation and energy input – must be understood. These elements singularly and collectively affect the conditions within an occupied building. Without understanding the relationships between these elements, finding the right solution to a condensation or mould growth problem can be very troublesome and incur needless cost”

I wouldn’t disagree with that, but would add in that the need to precognise and manage penetrating dampness often comes into play.

Heritage House says:
18 September 2013

Woops Peter – you are promoting the PCA again!!!!

Humble shrug of shoulders here…


It is difficult to know whose advice to accept throughout the whole of this conversation, splattered as it is with self-promotion, discrediting organisations, facts and factoids.
I found a document that was an interesting read, referenced earlier, that I repeat here, simply because it comments on a number or aspects of damp in buildings in what I see as a sensible way. Anyone with a damp problem might find it worth looking at.
No doubt “experts” will tear it to shreds? or maybe not.

Control of Damp – Historic Buildings Factsheet – HMSO.
I hope Which/ don’t mind me repeating this – but published information from a, hopefully, reputable source can only be of assistance in helping understand a problem.

I found that “eastcambs” document to be useful; thanks.

If nothing else it outlines the multitude of causes and remedies for damp, and will enable readers to spot parties that are pushing a “One True Cause/Remedy” point of view.

John Durie says:
19 September 2013

SPAB are an absolutely terrific organisation but referring to a document 17 years old in support of an argument is a bit thin. The National Trust for Scotland were using cementitious render on their castles in the 1970’s. They don’t do that nowadays. I suggest that perhaps SPAB have amended their advice since 1996.

John, I’m not supporting any argument – just putting what may be useful information to some looking at the possible causes of damp. The majority of the document discusses the many causes of damp – I doubt these are any different now than when the document was published.


We have to be careful here; as others have pointed out, it’s not an internet forum where we can discuss the existence of rising damp but rather somewhere to provide advice to members regarding their problems, hopefully pointing them in the right direction. It does no good to have moderators having to step in and rap knuckes.

If we do want to ahve said debate then I’m happy to set up a Linkedin group where we can do so.

In the meantime, and looking forward, I would suggest that you read the advice set out by Historic Scotland (our equivalent of EH) in their recent Inform Guide Damp – Causes and Solutions. This is available free on-line and does pick up the earlier papers by SPAB. It identifies the princple causes as poor maintenance, inappropriate materials/repairs, ventilation, and Condensation. The guide notes that impervious barrier methods are not generally appropriate as traditional buildings need to breath, and suggests avenues for investigation.

I have to say that I think that the EastCamb/SPAB document is also in the right end of the ball park.

The problem, looking at the various postings here, is that many – perhaps even most – of the damp “specialists” seem to go straight to chemical treatment/injected dpc/impervious Newlath type system. Conflicting advice is obtained from different firms. There are questions about the motives of some firms in making expensive recommendations, and likewise question marks about their surveyors wider qualifications.

This, I would suggest, takes us back to need for householders to be able to obtain professional, independent expert advice. Where the causes are not straightforward, then there is every reason to seek the input of a qualified building surveyor (usually MRICS) or conservation architect (RIAS/RIBA/AABC) with a strong track record in the care of traditional buildings. Yes, it might cost some additional fees but it will potentially save a lot of money and grief in the longer term.

I’m happy for you to discuss/debate the existence of rising damp on this post if that’s what you’d like to do. As long as you respect one another’s views and debate politely. Thanks

Robusto says:
19 September 2013


I look forward to partaking in the debate, but Which needs to moderate comments that stray into the territory of outright defamation. You might want to start with the “Agent Orange” comment above which can easily be proven to be false and has been posted by someone who has stated their intention to cause damage the industry in question.

If anyone is interested in the physics behind rising damp I suggest they look up “Rising Damp: Capillary Rise Dynamics in Walls” by Christopher Hall and William Hoff (Proceedings of the Royal Society) which is available to read free of charge online.

John Durie says:
20 September 2013

All – Public and professionals alike:
The advice I would give anyone is to ensure any treatment is reversible, it doesn’t do any harm to the operation of the structure, recognise that there isn’t one ‘magic’ solution – as is all too frequently proposed – and carry out basic and relatively cheap remedies first. Clean gutters, clear drainage, reduce ground levels, ventilate subfloor, ventilate rooms, then carefully seek out experienced people who will provide advice – not necessarily also carry out the work – as that is where many of the misdiagnosis ‘issues’ stem from.