Very bad condensation/damp

[lobatt]

Hi all, been having problems with a west facing rendered wall on a 1920's brick built semi.
For a couple of years or more, I have been getting mould and damp at low level in a first floor bedroom, we had the roof re-tiled with slate like tiles as the existing roof had just about had it, this was about 4 years ago, we noticed sometime afterwards condensation at certain times of the year in the roof space above the affected bedroom (beading all over the felt lining) as a result about 3-4 months ago I had roof vents fitted, this solved the problem of the condensation in the loft (at the time we thought the condensation and the damp were related), but the damp is still present in the bedroom. It is that bad, water forms on the top edge of the skirting, the wall paper is coming off the wall up to about 18 inches high, there is mould and the electrical sockets are wet and I mean dripping, with the back boxes now going rusty, it hasn't as yet affected any internal walls.
The rendering looks intact and the brick work on the other external wall to the bedroom (north facing) looks OK.

Any ideas? thanks in advance all

 

[freddiemercurystwin]

Ventilate ventilate ventilate!

End of Thread!

 

[lobatt]

Many thanks freddymercurystwin,
Is it best to fit vents/airbrick high or low on a wall?

 

[freddiemercurystwin]

Higher is good, surprised there aren't any existing vents, are there any visible on the outside or have they been rendered or plastered over?

 

[lobatt]

None at all, I had the room replastered a couple of years ago but nothing historical showed up in the brick work.

The problem didn't exist when we first moved in, but we had a new roof about 4 years ago (old one wasn't even lined) Put loads of insulation in loft and we fitted double glazing about 5 years ago.

It seems the same old story of trying to keep all the heat in to save money, but this causes its own problems

I will fit an air brick at the weekend about a foot from the ceiling in the corner, also be looking at the possibility of fitting a trickle vent to the window.

Should I try anything else, or would that be enough?

 

[freddiemercurystwin]

Fit the trickle vent first if you can as this will likely be easier and see how you get on. If you have nightlocks on the window then try that too first. Its always a compromise between keeping heat in and adequate ventilation. You can't achieve 100% of both.

 

[lobatt]

Had a look at the window frame, in regards to trickle vent. I think not enough of it is showing at the top (Wall was plastered after fitting).

I have just fitted a airbrick to one of the affected walls, was wondering wether to fit another to the other offending wall (The rendered one).

BTW Is it possible for the damp to come through painted rendering? or is this probably purely down to poor ventilation in the room.

I painted it a couple of years ago and coated with a stabliser first.

 

[Nige F]

before you mess up a rendered wall - try and eliminate the Source of the moisture - The bungalow I`m in now is a classic case - and got the place cheaper because of it . 2 yrs. ago we moved in and it was riddled with condensation . a typical old folk`s place . Never ventilated and couldn`t afford to heat properly . Killed the mould with bleach @ 50p a bottle . even had to replace the gaskets on the d/g windows @ 30p a meter - they had gone mouldy opened up the fireplace - had the walls and roof insulated . Some tit had actually fitted airbricks which only vented the cavity I made sure they fed air to the underfloor voids. extractor in the kitchen - fan in the bathroom . proper vented tumble drier. solid fuel open fire on occasions , the rest of the time use the heating - fitted some rad thermostats .simples.

 

[alittlerespect]

HI

One Question: Is this a cavity wall or a solid wall?

If it is a cavity wall, have you had cavity wall insulation fitted? If so does the problem only occur after a rain storm from the prevailing South Westerly direction, if so, you have the answer to your problem.

The solution would be a bit more painful to the pocket, i.e. remove the offending cavity wall insulation!

Regards

 

[lobatt]

Hi, no its a 1920's house just double skin brick.

 

[alittlerespect]

Hi

As its a one brick solid wall it sounds like either the verge detail may be wrong to the new slate roof as you never seemed to experience this problem prior to the new roof going on, or you are drying clothes off on hangers indoors but that would have to be a serious amount of washing to create that bad an effect.

Or as mentioned before, if the problem only occurs when you have heavy rain from the prevailing south-westerly direction, in which case the external render may be in poor condition, and if that is the case then either consider painting the wall to seal all cracks, or if its really bad arrange for the wall to be re-rendered and include a waterproofer additive in the mortar mix.

You could buy or hire an inductive type damp meter and see if you can trace the damp in order to get a better idea of where the water is entering the building.

Regards

 

[JohnD]

does anyone in your home drape wet washing about the house or over radiators?