Advice on Damp problems – are these damp specialists trying to make a quick buck?

Advice on Damp problems – are these damp specialists trying to make a quick buck?

10:26 AM, 9th November 2014, About 9 years ago 20

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To give you some background, I own a terraced property built 1888 which was later fitted with a dpc (drilled into brick) but I’m not sure how long ago this was. We refurbished the property 4 years ago, having all external walls re pointed and painted, we hooked off old damp plaster, allowed an industrial dehumidifier to dry out the walls before having re plastered etc. Advice on damp problems

Damp under bay window:

There are damp patches appearing under the bay window, I’m not sure if the dpc has failed here, but it looks like the tenant has had a virgin box installed that they no longer use. I have complained to virgin media that I believe the installation has caused the damp in the wall and this is under review. Damp specialists have advised me to pay to have an injected dpc under bay window but what are your thoughts??

Damp on rear window corner & lower internal partition wall:

A damp patch has appeared in the corner of the window, which looks like it moves down to the corner. Damp specialist also suggested having this injected dpc under the window and along, however it seems to me like that isnt going to solve the problem as damp starts heigh up.


Has the chimney breast separating the dining room to a small kitchen, the wall is extremely thick and is showing damp patches on the wall which rises higher than rising damp. We capped off the chimney and pointed the top to stop water from getting in so this water may just be trapped in the wall. The other wall in the kitchen, around the window white salts are appearing and this wall is damp also with crumbling plaster, the external wall is rendered so I’m not sure if the rendered external wall is causing a problem?

Damp specalist advised to have this dpc injected from the outside, to have kitchen taken out, plaster hacked off and replaced, however i dont think that would solve the penetrating damp (the kitchen walls are solid)

I’ve had a national damp specialist out but I’m unsure weather they are quoting unnecessary work. My issue is that I want to tackle the exact causes and then replace plaster etc so that it doesnt come back. It seems like the damp specialists are just plastering over wet walls and there is no guarantee that it will not come back.

Would anyone recommended having a building defect damp survey completed by an RICS member? If so, if their recommendations did not rectify the damp in the property would they be liable to fix? It looks like I am going to be paying out a few thousand pounds to try and fix this problem, I want to make sure it works.

Please help.


Andy Manning

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Mark Alexander - Founder of Property118

10:33 AM, 9th November 2014, About 9 years ago

Hi Andy

I feel your paid!

I too have had damp problems in houses and flats in the past and attempts to cure if resulted in me being ripped off several times.

Then I discovered positive input ventilation. The company I used were Envirovent, they were not cheap but they offered a money back guarantee if their solution didn't work so I went for it. I've not looked back since.

There are cheaper versions from Nuaire which by all accounts work just as well, however they don't come with the same guarantees so far as I'm aware and you need to hire an independent fitter. I've recently learned that Nuaire offer a one day free training course for fitters and you get a certificate at the end of it too. I'm looking into this myself but haven't done it yet.

Good luck and please let us know how you get on.

All BankersAreBarstewards Smith

11:36 AM, 9th November 2014, About 9 years ago

have you ensured all external water goods are doing their job properly ? do you have cavity walls (maybe there is old builders rubble fallen into it which is creating a bridge between the two walls which allows damp to penetrate - or do you have wall ties - maybe they have rusted through and are allowing water ingress ) or do you have a single skin wall - in which case check your pointing from gutter to ground.

Hairline cracks in rendering are a pain to find and they can let in a lot of water.

intermittent injection here and there will only make any water ingress move somewhere else and wont solve your ongoing problem.

Why not talk to a local builder first and get their view ?

Properties of this age do suffer quite badly from damp and can take a while to cure.


15:19 PM, 10th November 2014, About 9 years ago

Injected chemical DPCs are notoriously unreliable as you can never be sure that the chemical is really getting into all the brick cavities that might transmit water. They are also extremely expensive as the installers always recommend hacking off the plaster - then blame the plaster for causing the problem if it re-emerges. See comments by ubiquitous DIY adviser Jeff Howells, or the article on Rising Damp at

When you say "under" the bay window, do you mean at floor level, or underneath the window frame. If the latter, you clearly don't have rising damp, and "damp" mould caused by condensation of internal warm air usually occurs in the corners of rooms, where circulation is poor and temperatures are colder.

I'm also sceptical that installation of the Virgin box has caused the problem: they usually drill slightly upwards, so any external water run-off cannot enter the building, and install plastic caps at either end of the hole.

Have you checked whether you have a leak on your bay window, either round the wooden frame or possibly from the roof? If the water is getting in between the roof and external brick wall, it may be running down the window frame adjoining the brick wall and emerging underneath the window.

Joe Bloggs

16:31 PM, 10th November 2014, About 9 years ago

is there is black mould? if so then it is most probably condensation.

Mike W

17:23 PM, 10th November 2014, About 9 years ago

I would suggest getting a number of good builders to have a look. Maybe other damp specialists. I'm afraid I'm not a believer in injection methods but I am no expert.
One thing you will gain from getting builder's and other specialists is a lot of free expert knowledge. Then you will be in a position to know who is giving you the best reliable story.
I would like to know how you get on with a surveyor. My inexpert view is it will cost a lot and recommend a lot and not necessarily solve your problem.
I had a penetrating damp problem in a kitchen with solid walls. I stripped back to the stone. I sealed the wall internally, created a small gap with wood battens and used insulated plasterboard internal lining. Its worked fine for 5 years but I know it is not the best solution and I may have to do some rework in the future. But its a warmer room.
I will read other suggestions with interest.


17:51 PM, 10th November 2014, About 9 years ago

Hi Andy

I have a house built 1890 solid wall 9inch, I have had terrible problems with damp.
It was suppose to have had a dpc when I bought it but was still damp.

I had the damp companies out )and was advised to tank 1 metre up all around, this I did
still have seriously damp problem.
It started as a damp patch the size of a saucer above the 1 metre high tanking last year . I know it was very wet, all the damp people wanted to inject or tank again.

I paid for a RICs surveyor £100, he told me it was rising damp , as it was unable to
come out lower down due to the tanking on the inside and the textured coating on the outside.
He advised a french drain, which we have done,.

Next June I will remove the textured coating on the outside, it needs to be grinded off and is very very expensive. I wish I had render as that would be much easier to remove.

I will then lime render the property as the bricks will be damaged, this will enable the property to breath.

I spent about a year talking to different people and having many people out to the property. Look up this old house on net .


19:21 PM, 10th November 2014, About 9 years ago

A building dating from 1888 is victorian so will have solid walls and timber floors. It would have been built with coal fired hearths, leaky sash windows and lime mortar walls. This technology relies on good ventilation to keep rhe hoise damp free bit by cement pointing,.installing double glazing, injecting dpcs etc you are fighting against the.original principles and the damp will win.

I hope you house is not built of soft reds. If so get rid of the cement pointing at the next.big refurb. Cement pointing is a post war timebomb but harder bricks will be less adversely affected.

Anyway damp proofing companies have a license to print money and their guarantees dont hold up to close scrutiny. Avoid and use common sense.

As someone said earlier sort out ventilation. You need supply of air via chimney vents, trickle vents etc. then you need an extract. Ventaxia do a nice one for social landlords which is good for tenanted kitchens and bathrooms. It runs constantly on, low noise and energy. Then steps up a gear based on a humidistat. Train your tenants on opening windows/not drying washing indoors etc without ventilating. Add window locks which allow secure trickle ventilation. That is the main course of action.

Yourbay window. If yoir windows are high performance and the ventilation is poor then condensation will probably hit the walls. This probably explains the spurious patches of damp at high level. I agree your virgin box might be a cause of problems. Get ridand minimise fixings.into the brickwork as they ask foe trouble.

Chimney was capped but did you seal it? You need a vent at the base, a well pointed stack and good flashings. You can buy a hat for the pot to keep rain iut. If you have sealed the void i am nit surprised there is an issue.

If you had damp treatment it may never let the walls dry as it concealed rather than dealt with the source. So it might be tricky to figure out in one easy hit but over time it should work out. Good luck and if that makes no sense find a reccomended surveyor ir a neutral damp person like floydconsult


20:25 PM, 10th November 2014, About 9 years ago

Hi guys,
thank you all so much for your time to read my situation.

To answer some questions, when doing the property up we replaced all of the gutters, we've even replaced the waste pipes as we came across a crack close to the wall of the house so we know the water running away from the house is doing its job. I've rechecked the guttering and everything is working fine.

I've asked one of the gas fellas i've used for many years if he has come across any honest reliable builders so one is coming out to me Wednesday.

Under the bay there are damp patches on the 3 walls \__/ .. funny you should mention ventilation in the room as I did have to move the tenants couch out the way to take a look.. I've gave her a dehumidifer and it seems to have dried up abit.

The Kitchen still remains a problem for me. my research and my mind is telling me that the Render on the walls external is not helping at all. I may remove this and ask to be repointed with a Lime Mortar but apparently this lime mortar doesnt work well with frost?

Chimney Stack in kitchen - I don't know if it would be a good idea to install an air brick off the chimney stack to make sure it never came back from the chimney stack.. what do you think?

20:39 PM, 10th November 2014, About 9 years ago

It's essential you get impartial advice before spending money.
Damp PATCHES on outside walls are usually penetrating damp. if you have no cavity the thickness of the wall is no barrier to you have a few options including paint and render outside or membranes inside. Silicone spraying of bricks can work but only for a few years....
rising damp normally occurs up to a metre from the floor - if you have damp above it is not rising damp. Rain ingress can be noted round windows or below windows.
Damp patches on cavity walls can show defects to the wall ties (often)
None of it is easy to diagnose so do some home work BEFORE spending money.....try ......... we try to give honest advice and have been in the damp business for 30 years!
Best wishes

David Sanderson

20:55 PM, 10th November 2014, About 9 years ago

Wow, hats off to anyone who can give correct diagnosis of the issues as described via an internet forum.
A true diagnosis requires an independent and experienced surveyor to look at it. Even then you might get a different diagnosis for every professional who looks at it.
Good luck

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