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Damp Proofing Questions

Our expert damp proofers have kindly agreed to share their wisdom on such topics as removing mould patches, rotten timber, causes of mildew, damp basements, rising damp, floor construction, flooding and waterproofing and much more.

1,014 Damp Proofing questions

Need someone to advise on best way to tackle dampness issues?

Hi- I would like to get someone out to our house to give advise on what steps we need to take to improve dampness within the house- currently upstairs 2 of the bedrooms seem to have a bit of a damp problem- but we are not sure, whether it is a roof issue- if the windows need replacing, if the cavity walls need insulating or all of the above. We would like to have someone to come and have a look and provide advise on what is best to do.

What should I do to get rid of the damp in my house?

A few years back, our house seemed to have insulation problems and so we had a specialist check the whole house and fix the problems, so the insulation was fixed in the attic, the doors and other places around the house. Both before and after this, we had a little bit of damp/mould appearing in the house, but only in one room upstairs and the roof of the bathroom (assuming this is what is called penetrating damp).

Since it got very bad, we had someone come to fix it, which included them adding a damp sealant in the places it was bad inside the house, putting a fan in the bathroom, and replastering all the walls inside, then painting over them.

AFTER that, our damp problems are a lot worse than before: damp is appearing in every single room, it is appearing on the tiles in the bathroom (even though there is now a fan which we didn't have before), it comes very quickly so pretty much needs to be cleaned every single day, and there is a lot of build up of water on all the windows and the house is always cold.

We don't know what the problems is or how to tell what the problem is, how to fix it, who to call, or what options there are. We just really want to get rid of this damp problem.

I'm confused about everything really, I read an external coating should be applied to stop moisture getting into the house (which needs to be reapplied every few years, such as Stormdry?), or that the brick walls and roof need to be completely sealed (but then people debate over "breathable" coating and one that is a completely waterproof sealant, or a lime seal thing I don't know), or that the problem is internal and something was done incorrectly (maybe insulation or something).

I am extremely confused and irritated because we had a small amount of damp before (in comparison to now), spent a lot of money thinking we'd finally solve all the problems, then it comes back much worse. I know that was long but please could someone help me out here? I know nothing and the damp is bloody everywhere.

Is it possible to damp proof my wooden floor boards that lie over a sub floor?

Is it possible to damp proof my wooden foorboards? I get water under my sub floor when it rains heavily and i would like to put laminate flooring down over the floorboards but i am worried that the water under the boards will lead to the laminate flooring getting damp and warped. Any suggestions?
Kind regards

Penetrating damp due to leaking gutter

Hi, I have penetrating damp in the corner of a first floor bedroom due to a leaking gutter. The house was built in 1936 and the outside wall is painted pebbledash with a smooth rendered corner. I can't get to the wall inside and the outside is damp due to continuous rain. Can I use a water seal product just on the affected corner as a temporary measure until I can get the gutters sorted out? Can any of these products be applied over damp paint?

Black mould since PVC double glazing fitted.

Hi - seeking advice regarding a purpose built 1960s ground floor flat which has suffered condensation and black mould in the outer corners of the walls and low on the outer walls since PVC double glazing was fitted, replacing the original wooden single glazed windows. Filing under 'Damp Proofing' but not sure if there is a better category.
The first thing tried was to make sure the trickle vents were open - they were and they are. Then since no ventilation was fitted in kitchen or bathroom extractor fans were installed, the bathroom unit follows the light switch, i.e.no timer, the kitchen extractor just on a pull switch.
There being no improvement and the flat remaining very humid a Passifier vent was fitted low in the outer wall of the worst affected, and coldest room.
The last recommendation has been to fit a Flatmaster 2000 Low Energy Positive Input Ventilation Unit but this advice has not been taken up. The above work was all recommended by ventilation specialists. Lastly the occupier's lifestyle was blamed for the trouble, being out all day and leaving the flat unheated, in addition to running a cloths drier in the bedroom, albeit vented out of an open window.
The flat has wood block floors over concrete and has recently been inspected by a Chartered Surveyor who pronounced it to be structurally sound.
The property now needs treatment for the existing mould and considerable investment in full refurbishment. We plan to include a humidistat extractor in the bathroom this time, and an extracting cooker hood over the kitchen hob, but no plans to go for the Flatmaster.
My worry of course is that all this will be for nothing and the mould will return.
What advice would you give please on the Flatmaster, or any other device or method we could apply to maximize our chances of success?
Thanks for your attention, your advice eagerly awaited.

28/11/14 -
Lee - Many thanks for your feedback, I was not aware of systems like that and it looks very effective. Much obliged, thanks.

How do I fix this damp problem in upstairs bedroom?

One of our upstairs bedrooms has damp on the internal front wall and into the corner. It seems to be about half a metre square coming from the skirting board upward. The rest of the room seems unaffected. It has upvc double glazed windows and the external wall is rendered. There maybe early signs of damp in the corner of the corresponding ceiling in the room below.

rising damp in a very old building Victorian house

hi i have bought detached house that converted to two flats about 2 years ago the building it self showing sign of rising dump i have drilled out side the walls all around the house, and inject the cream into the walls
my main problem is down stairs in the shower room were i have injected inside and out side the wall put completely new sand and cement into the walls after we strip it to brisks and yet still after 4 weeks i have patches in the wall that not dried and still dump what do i do i cant put tills and put back the shower until it completely dry and its not.
there is no pips only in the floor (when we strip the wall we did not see any pips on those particularly patches this is second time i had to take out tills and shower what do i need to do ) please help me

wet patches on wall

Hi, I'm in a ground floor flat with three other levels above me. I have two wet patches underneath my window on an exterior facing wall which get worse anytime it rains. the dark patches are permanent now but the wall becomes wet on the surface, this dries out when i open a window. There roughly a meter apart and rise up from above the skirting board.I had a surveyor have a look and the only explanation he could think of was it being related to the drainage pipes. I dug up the garden and the down pipe had became slightly disconected from the trap, leading to the hole filling with water during rainfall or during a neighbour running a washing machine. I had this fixed two weeks ago assuming this would be the cause but the problem hasnt cleared up. Does anybody have any other ideas as to the cause? this problems starting to do my head in so any help would be greatly appreciated.

its an old building probably around 1900 made of stone


Visible damp on screed in 1950s house

I recently bought and moved into a 1950s house which had the same owners for the last 54 years, and their maintenance on the property during that seems to have been minimal. We're undecided on what to do with the ground floor flooring so ripped out the old carpets for the time being and exposing the screed (which we think is covering a concrete floor). The screed looked to have old damp stains but nothing that caused us to worry until today. We decided to move the furniture around in the living room and found that underneath where the furniture had been standing there is visible moisture sitting on top of the screed. I'm really worried about what is causing this and that is going to cost a lot of money to repair. Has anyone experienced anything like this?

Large damp patch on 1st floor chimney breast

Last week a Large (1 Meter sq) damp patch appeared on the internal chimney breast on the first floor. The patch was wet to the touch and there are patches where the chimney breast protrudes front the wall in the upper comers. The damp patch has not dried out but is not getting any larger. I am not sure how it has appeared or what the solution will be. The wall will need redecorating, but I need to identify the route cause first. Does anyone have any experience of this type of damp?

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