Blocked air vent - mould inside the cavity wall?

Joined
18 Feb 2015
Messages
13
Reaction score
3
Location
London
Country
United Kingdom
Hi there,

I hope you can help! I live on the top floor of an ex-council flat built in the 50s. The building has cavity walls and the windows have upvc double glazing (of poor quality). There is gas heating in the flat with the boiler in the kitchen. The living room has a vent in the old fire chimney but there is high humidity in the room because mould is forming on the plants soil. There is no visible mould on the walls and no unpleasant smell in the room. The main bedroom had an air vent in the old fire chimney but I blocked this up (for soundproofing reasons). Again, I have no issue with damp or unpleasant smells in this room.
The problem I have is the spare bedroom!! When I moved in my flat there was an air/brick vent in the external wall of the bedroom, aprox 30 cm from the ceiling. This was made of a few holes in both cavity walls so if I looked through I could see outside. I had to block the vent for soundproofing reasons. I simply stuffed some paper inside the holes and then I filled the holes on the inside wall with filler. I couldn't reach to fill the holes in the external wall as the filler would just fall in the cavity. I then let the room out and did not notice until months later that my lodger was drying her clothes in her bedroom without ever opening the windows. As a result there was a bit of mould growing on the walls and windows. My lodger eventually moved out and I cleaned the walls and left the window open all summer. I did not have any mould since then. However, every time I go in the bedroom I notice of strong smell... I can't really identify it, it doesn't smell clearly of mould or damp, it smells of dirty wet socks, as if I never ventilate that room. The smell is much worse when the heating is on (the heater is on the external wall). I have laminate flooring and that the curtains have been cleaned and aired. I also noticed that the wall surrounding the blocked up air vent is cracked, but I am not sure if the crack was there when I moved in.

I wonder if it is possible that the smell comes from the blocked out vent? If I only filled in the internal wall and the holes remained in the external wall is it possible that rain water got in and mould formed in the cavity?? But could this be possible if the air in the cavity is as cold as outside, plus there would be too much surrounding ventilation to allow mould to form? Or perhaps the smell lingers since the time when the room had mould (unlikely as this was a year ago). Is there a way to block the holes in both walls given that I can't get access to the external wall from the outside (flat is on 4th floor)? How do I identify where the smell comes from? Does anybody have any suggestions as the smell is driving me crazy!

Thank you!
 
Sponsored Links
A very dumb suggestion - check behind radiators/pipework.

The oldest trick in the book is to put something there that will stink when it gets hot!

(Fish & cheese used to be favourites)
 
Haha, how I wish this was the problem! nope, there is nothing behind the radiator :(. I think i have no other option but to break inside the vent and see if there is anything smelly in there. I am really not good at DIY stuff so i hope I wont end up with a big hole in the wall.
 
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top