Significance of damp concerns

[Henryc]

Hi- we're FTB of a Victorian 19th century end terrace property and have recently completed a L3 survey which highlighted some concerns. One of these concerns was high meter readings for dampness in the party wall on the ground floor.

We had therefore requested a visit and quote from a damp specialist (changed to the damp proofing company in the following posts) who after inspection quoted £8k for the chemical injections, tanking as well a removal of skirting/ replastering etc- which did seem excessive after reading some posts online. We also understand that often times this will cause more harm than good in a lot of period properties to impact breathability and force the dampness elsewhere (i.e. other side of the wall or worse through the ground).

1- is this true with a lot of period properties and how significant can this dampness be/ become? There are plenty of posts which suggest finding the source of the dampness is the key thing here but how do we go about this especially as we don't yet own the property and mindful that the current owners may not agree to any invasive methods to investigate?

2- is the quote genuinely unreasonable and may not hold up well as a negotiation tool? We're considering getting a independent damp surveyor (one who doesn't need to push sales of these injections etc)- has anyone had experience of getting a more realistic and accurate report this way? If so what kind of costs on average should we expect for such a survey/ inspection as (the inspection from the damp proofing company) was free.

Any feedback on how best to proceed would be much appreciated!

 

[stuart45]

That's the problem with a free damp survey. 8 grand for party wall is really high. You might be able to negotiate some money off the price though.
Finding a truly independent damp expert can be quite tricky for people not in the trade.
A damp meter isn't really an accurate guide to damp masonry.

 

[malcolm]

Does the wall actually look damp? Wet patch, peeling paint, rotting skirting etc? Do post a photo showing the problem. The damp idiagnosis might not be accurate.

If there is a problem then waterproofing and tanking is not a good solution. If you really have damp the problem is more water getting in than can get out and making the wall more waterproof will make the problem worse.

 

[Henryc]

Does the wall actually look damp? Wet patch, peeling paint, rotting skirting etc? Do post a photo showing the problem. The damp idiagnosis might not be accurate.

If there is a problem then waterproofing and tanking is not a good solution. If you really have damp the problem is more water getting in than can get out and making the wall more waterproof will make the problem worse.

Thanks for this. Not severely but there was noticeable discoloration in the corners of the kitchen next to the party wall (attached) which seem like wet patches but aren't wet to the touch. Otherwise no obvious signs of damage or wet patches directly on the party in question and have based this on the L3 surveyor and the (the damp proof company's) damp surveyor's reports of high readings (2nd picture).

 

[malcolm]

The discolouration on the ceiling looks like someone repainted the walls and the edges of the ceiling but then didn't paint the ceiling. Kitchen ceilings can get a bit discoloured with cooking vapours. I would completely ignore the damp meter readings. Damp meters aren't measuring water content when used on plaster.

Can't see a problem that needs fixing.

 

[aockenden]

Discoloration can certainly be historical and not necessarily indicate an ongoing issue. Especially strange that it doesn’t feel damp to the touch… sketchy!

 

[Lacan07]

Hi- we're FTB of a Victorian 19th century end terrace property and have recently completed a L3 survey which highlighted some concerns. One of these concerns was high meter readings for dampness in the party wall on the ground floor.

We had therefore requested a visit and quote from a damp specialist (Kenwood) who after inspection quoted £8k for the chemical injections, tanking as well a removal of skirting/ replastering etc- which did seem excessive after reading some posts online. We also understand that often times this will cause more harm than good in a lot of period properties to impact breathability and force the dampness elsewhere (i.e. other side of the wall or worse through the ground).

1- is this true with a lot of period properties and how significant can this dampness be/ become? There are plenty of posts which suggest finding the source of the dampness is the key thing here but how do we go about this especially as we don't yet own the property and mindful that the current owners may not agree to any invasive methods to investigate?

2- is the quote genuinely unreasonable and may not hold up well as a negotiation tool? We're considering getting a independent damp surveyor (one who doesn't need to push sales of these injections etc)- has anyone had experience of getting a more realistic and accurate report this way? If so what kind of costs on average should we expect for such a survey/ inspection as Kenwoods' was free.

Any feedback on how best to proceed would be much appreciated!

Avoid (this damp proof company) like the plague, or another major damp proof company for that matter. (This damp proof company) quoted the previous owner of my house 25K for DPC injection and tanking and when I investigated the problem it was just high external ground and a terrible retro-fitted concrete floor in the kitchen. As others have already said I can't see the problem in your photos, and those damp meter readings will be an absolute crock of s**t

Edit: I just thought I'd add that both the damp proof surveyors and the standard surveyor missed the concrete floor in the kitchen that had breached the slate DPC on the one internal that was the most damp out of all the walls. It was fairly obvious to me that this floor was a major issue because I very quickly took the wall down to open up the kitchen into a kitchen/diner area and the damp was obvious. The floor / joist had also suffered here because they buffered the wall. This is just one example of how discreditable these people often are.

 

[malcolm]

I've removed the name of the company from the posts. It's common for companies to have reputation management people who go around the internet using heavy handed tactics to try to censor any less than positive comments. The name of the company itself is not important here.

Though any company offering expensive products that also offers a free survey so you can find out if you need them might not offer an unbiased survey. Worse than that is the mainstream damp industry ignores the basic strategies that have kept these houses dry for hundreds of years (breathability) and instead doubled down on adding more of the stuff that has made them damp (waterproofing). Far better off asking on the forum instead.

 

[stuart45]

I've removed the name of the company from the posts.

I can still see it in brackets in the first post.

 

[Toby Newell]

The very honest, knowledgeable, (if arguably slightly 'religious' to everything natural and organic) people at heritage-house.org charge about £3k for a level 3 RICS. What you will get is an honest opinion that focuses on retaining originality and maximising breathability, albeit one that is heavily biased against any chemicals and favours anything made with lime, sheepswool or linseed oil. So, pinch of salt in hand, you will still get a more honest opinion than any salesperson masquerading as a damp expert or surveyor. I have worked alongside and seen reports and previous work from the biggest three damp / pest / subsidence companies and I haven't been particularly impressed. They seemed to charge multiples of my rates for less work, much of it not up to a standard I would be happy with and much of it simply needless. It's not an exageration to say I was very surprised at the quality of their work, and their methods, especially considering the price. It actually made me feel much more confident in the work that I do! (Until I realised how poor it was) I was expecting them to be in a different (higher!) league to myself. There is nothing I have seen that they do that a conscientious builder or confident DIYer couldn't do for a fraction of the price. I think their MO is to prey on the general ignorance around these issues and that includes not just Joe public, but qualified surveyors and RICS itself, to often over specify needlessly and possibly detrimental 'solutions' that are easy for them to execute and maximise their profits. Correctly identifying and pinpointing damp issues, which may have several contributing factors, takes a lot of experience and sometimes involves trying more than one solution and waiting weeks or months to see the results. Drilling holes and hacking off plaster is often akin to using a sledgehammer to crack a nut. And often one where the sledgehammer misses the nut completely and smashes the table.

Luckily there are many experienced people on here with very astute, factual and helpful advice some of which you have already received. The bloke in the picture has a Protimeter, which is a great machine but point readings are totally meaningless without context. Roof, windows, gutters, pointing, check for leaks / damage, (check lime pointing not replaced with cement) ground levels, check for excessive height / lack of fall / reverse fall, splashback, airbricks - check for blockage and height above ground, foilage etc. Checking for missing or broken DPC and replacement with injection (you can do yourself for a few hundred £ btw these days, including buying a new drill and bits) should be near last on the list.

Even if it turns out (as in the extreme MINORITY of cases of only a few percent) that the DPC or lack therof is in fact the problem and that injections are a solution then adding tanking to the mix is often still a pointless waste of time and possibly also deleterious. The only real reason to hack off gypsum plaster / lime is if it is heavily contaminated with hygroscopic salts, even then it would be best to replaster with lime. If you have solved the damp issue then tanking with a waterproof render using Sika 1 etc makes no sense, it's just a money maker. If you live near the sea or on top of a hill with exposed elevations and receive wind driven rain then it's better to waterproof the outside over the inside. Unless you are talking about a basement or a lighthouse then making your internal plaster waterproof is almost always a bad idea. You can guess why firms do it! Seeing as most DPC injections don't actually solve the underlying damp issue, waterproofing the interior at least stops the appearance of damp coming through at least until the cheque has cleared!

 

[Toby Newell]

I wish civilisation hadn't temporarily regressed into this divisive zero sum game of right or wrong. Even in post graduate science 1 plus 1 doesnt always equal two, negative square roots are a thing and matter can spontaneously appear from nowhere. There are exceptions to almost every rule, maybe with the exception of the speed of light and the conservation of momentum, information and energy.

Rising damp is a real phenomena, bricks and mortar are porous, chuck a brick in a bucket of water and otherwise explain where the air bubbles are coming from... In some, relatively rare cases where subsidence or heave have broken the slate DPC, or where mortar snottings or other debris has fallen inbetween uncapped cavity walls and bridged the DPC or where removing any bridging layer is unwise due to structural concerns a drilled DPC can be beneficial.

It's just that most buildings with an original DPC and rising damp have the DPC bridged physically with concrete slab / paving or via splashback which can oftenbe remedied via removal. And those buildings without a DPC will often benefit from a more holistic multi point solution focussed on reverting back to the original level of breathability.

If you are running an honest damp rectification company your top header should read 'It's complicated...' but complicated = less sales. Instead often their top banner is 'Rising damp' because drilling holes and hacking plaster for over inflated prices is perhaps some of the most profitable work out there.

 

[Henryc]

The very honest, knowledgeable, (if arguably slightly 'religious' to everything natural and organic) people at heritage-house.org charge about £3k for a level 3 RICS. What you will get is an honest opinion that focuses on retaining originality and maximising breathability, albeit one that is heavily biased against any chemicals and favours anything made with lime, sheepswool or linseed oil. So, pinch of salt in hand, you will still get a more honest opinion than any salesperson masquerading as a damp expert or surveyor. I have worked alongside and seen reports and previous work from the biggest three damp / pest / subsidence companies and I haven't been particularly impressed. They seemed to charge multiples of my rates for less work, much of it not up to a standard I would be happy with and much of it simply needless. It's not an exageration to say I was very surprised at the quality of their work, and their methods, especially considering the price. It actually made me feel much more confident in the work that I do! (Until I realised how poor it was) I was expecting them to be in a different (higher!) league to myself. There is nothing I have seen that they do that a conscientious builder or confident DIYer couldn't do for a fraction of the price. I think their MO is to prey on the general ignorance around these issues and that includes not just Joe public, but qualified surveyors and RICS itself, to often over specify needlessly and possibly detrimental 'solutions' that are easy for them to execute and maximise their profits. Correctly identifying and pinpointing damp issues, which may have several contributing factors, takes a lot of experience and sometimes involves trying more than one solution and waiting weeks or months to see the results. Drilling holes and hacking off plaster is often akin to using a sledgehammer to crack a nut. And often one where the sledgehammer misses the nut completely and smashes the table.

Luckily there are many experienced people on here with very astute, factual and helpful advice some of which you have already received. The bloke in the picture has a Protimeter, which is a great machine but point readings are totally meaningless without context. Roof, windows, gutters, pointing, check for leaks / damage, (check lime pointing not replaced with cement) ground levels, check for excessive height / lack of fall / reverse fall, splashback, airbricks - check for blockage and height above ground, foilage etc. Checking for missing or broken DPC and replacement with injection (you can do yourself for a few hundred £ btw these days, including buying a new drill and bits) should be near last on the list.

Even if it turns out (as in the extreme MINORITY of cases of only a few percent) that the DPC or lack therof is in fact the problem and that injections are a solution then adding tanking to the mix is often still a pointless waste of time and possibly also deleterious. The only real reason to hack off gypsum plaster / lime is if it is heavily contaminated with hygroscopic salts, even then it would be best to replaster with lime. If you have solved the damp issue then tanking with a waterproof render using Sika 1 etc makes no sense, it's just a money maker. If you live near the sea or on top of a hill with exposed elevations and receive wind driven rain then it's better to waterproof the outside over the inside. Unless you are talking about a basement or a lighthouse then making your internal plaster waterproof is almost always a bad idea. You can guess why firms do it! Seeing as most DPC injections don't actually solve the underlying damp issue, waterproofing the interior at least stops the appearance of damp coming through at least until the cheque has cleared!

Thank you so much for the detailed responses- much appreciated. Will definitely try to be mindful of this. Also slightly relieved now to hear that this Protimeter perhaps isn't too reliable without understanding the wider picture.

 

[Toby Newell]

Thank you so much for the detailed responses- much appreciated. Will definitely try to be mindful of this. Also slightly relieved now to hear that this Protimeter perhaps isn't too reliable without understanding the wider picture.

The accuracy of the measurement device is irrelevant without context and can be used to push alternative narratives. For example, it could be showing internal condensation from inadequate ventillation and as heat rises the wall near the floor will be coldest and thus have the most condensation and thus show to be the most damp. This may or may not have anything to do with rising damp. Readings from whatever instrument are therefore meaningless without context and further investigation.

 

[Toby Newell]

Another example. Two blood samples from two patients show identical elevated intrasmuscular fat levels. High intrasmuscular lipids are typical in obese subjects and those with type 2 diabetes. They are also found as a rare adaptation in incredibly highly trained endurance athletes, for example, in Olympic distance runners.

So. Without looking at other blood results, eg HDL / LDL level, blood glucose or a photograph of each subject you would have no idea if you were looking at figures from a 20 stone man who spends his time eating cheesy wotsits on the sofa in his pants, or Mo Farah.