cause of WALL DAMP & how to rectify the problem

Dear Forum,

We recently bought our house which has ventilation in every room on the walls near the ceiling end. The wall on some of the rooms are damp. We are not sure whether it was the climbing trees/plants, ventilation problem or something else. Thanks again for your help.

1) Kitchen wall - the wood fitter detected the damp on the wall under the window but it feels dried inside as the plaster is broken. However, there was some plant bushes on the outside which are now removed and the outer wall of this area looks a bit darker. We detected a damp on the upper wall a meter away when stripping out the wall paper. Upon inspection, there were alot of ivy and other climbing plants on the outside wall which are now removed.

2) Dining Room - the wall paper near the air brick (the inside air brick is blocked) felt damp when were were removing the wall paper and the wall has some greenish mould. The outer wall (brick) near the downpipe and looks a bit darker. All the downpipe and gutter are now replaced but we are not sure whether it would cure the problem.

We would like also invite a damp specialist but are not sure how to look for a good one. What qualification we need to ask for?
Many thanks for your help.

What do you mean by "damp" - actual wet patches or black mould

^woody^ said:

What do you mean by "damp" - actual wet patches or black mould

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Hi, thanks for responded. it was not soaking wet as such but we felt the wall paper and the wall cold and not dry compared to other places. Hope this clearer

The eye is much more reliable than the hand. Wall plaster may feel damp, but you probably wont know it it is damp .... or just cold.

If you have a damp problem, then you will have patches of visible damp, and associated staining.

Parts of rooms will be colder than others and will be "damper" as plaster absorbs moisture from the air naturally where walls are cooler

From your post, I can't see a problem, so unless you can post some images or expand on this dampness, then you may not have a problem.

Having said that, Ivy is bad for walls and bordering on crap, so should be removed on that basis alone.

Check your gutters, check brickwork or any bad mortar joints, and window cills

Do you know if you have cavity walls or solid? Cavity walls are much less likely to experience penetrating damp, and solid walls only in extreme circumstances

Hi Woody, much appreciated your comments.

We have a solid wall. I will try to take some picture this weekend (we don't live in our new home yet) and post them for your comments.

Thanks again

Don`t waste your money .

The airbricks in every room are just "old school" building style. You don`t mention any form of heating in the house. It just needs warming and drying thoroughly over the heating season, leave the airbricks until next spring, then you can probably cover them , they are only substitutes for open fires to ventilate the rooms.

If you don`t want to wait before you start decorating, you could get a de humidifier in

Nige F said:

Don`t waste your money .

The airbricks in every room are just "old school" building style. You don`t mention any form of heating in the house. It just needs warming and drying thoroughly over the heating season, leave the airbricks until next spring, then you can probably cover them , they are only substitutes for open fires to ventilate the rooms.

If you don`t want to wait before you start decorating, you could get a de humidifier in

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Hi Nige, We have the whole house installed with new radiators. That right the house used to have fireplaces in almost every room including beddromm. Can I confirm my undstanding is that I can block the airbrick? Can you pls explain why I need to leave them until next spring because we are decorating the house now. and what is de-humidifier ? Thanks

HelpDIY said:

Nige F said:

Don`t waste your money .

The airbricks in every room are just "old school" building style. You don`t mention any form of heating in the house. It just needs warming and drying thoroughly over the heating season, leave the airbricks until next spring, then you can probably cover them , they are only substitutes for open fires to ventilate the rooms.

If you don`t want to wait before you start decorating, you could get a de humidifier in

Click to expand...

Hi Nige, We have the whole house installed with new radiators. That right the house used to have fireplaces in almost every room including bedroom. Can I confirm my understanding is that I can block the airbrick? Can you pls explain why I need to leave them until next spring because we are decorating the house now. and what is de-humidifier ? Thanks

Click to expand...

Hi, not sure if you've sorted this out yet but like the previous guy states, yes if the house is empty at the present then, it's more likely to be moisture rather than damp, so a de-humidifier is a good idea. A de-humidifier can be rented and it's a device that extracts the moisture inside the property that is gathering as molecules and is not being extracted through either, a natural air flow, or an electrical air flow. /stagnant air really. The de-humidifier then gathers this moisture into a container which you then empty into the sink. These humidifiers need to be on for roughly 2 weeks depending on how much moisture your property has attained. Usually when a property is 'lived' in the use of a heating system deters this moisture gather up, or if theres a good air flow either by having open windows, or extractor fans. Usually when the property remains empty especially over the winter months the air moisture inside the property becomes as cold as the outside, hence the moisture build up in the property which is usually more noticable on the windows. If the de-humidifier doesn't solve this problem, I recommend having a building surveyor take a few readings for you on the walls to determine if it's rising damp. A protometre is what they use, it's placed on the internal walls and it gives off a reading. if the reading goes above 45, then it's usually rising damp, below this reading usually means moisture through lack of ventilation. But you'll know which avenue to take. If the protometre doesn't give a proper indication, then request a speedy test, in which they take a core sample of the mortar on the internal walls. This gives you a definite answer. But I'd give the humidifier a try first of you already haven't.