Condensation problem

[bullethead123]

Hi all, I have a (tenanted) ground floor flat which suffers from condensation. It's particularly bad in the bedroom, probably because it has 2 o/s walls.
The bathroom (no window) has an extractor controlled by a humidistat, the kitchen is in the living area (no door).
There are storage heaters on both walls of the bedroom and a trickle vent in the window.
I'm considering installing vents (well, drilling holes really) at a high level in the 2 corners of the Room where the condensation causes the most problem.
As the flat is part of a purpose built block, would I need any permissions?
Are there any pitfalls I may encounter (DPC breech perhaps)?
Thanks in advance.

 

[bullethead123]

Any ideas anyone.
I appreciate that moist air is going to condense on the coldest surface, hence the idea of ventilation holes. Can anyone give me an idea if;
a) I'm wasting my time.
b) I should drill holes at bottom (or top and bottom)
c) I should install a duct (bit of plastic pipe)bridging the cavity.
Thanks.

 

[flameport]

Holes in the external wall will almost certainly require permission from those who own/manage the block, and it's also very likely they will say no.

Before making holes or anything else, you need to establish where this excess moisture is coming from.
The usual culprits are no extractor in the kitchen (or a useless recirculating type) and people hanging wet washing around the place.

Even with extractors, there is no guarantee they are actually used, and they also need somewhere for the air to enter the building from outside, preferably as far away from the extractor as possible.
Unfortunately some buildings are virtually air tight, so no extractor can work properly.

 

[bullethead123]

Thanks for the response Flameport. Of course, it's obvious now I'll install a hob extractor and change the washing machine for a condenser washer dryer.
Regarding the hob extractor, there's a duct that runs through the kitchen (& through the bedroom) from the bathroom extractor fan. Would you think it would be possible to vent the hob extractor into that?
Also, given that the duct runs through the problem bedroom, how about cutting my ventilation holes into the ducting too?

 

[mointainwalker]

Regarding the hob extractor, there's a duct that runs through the kitchen (& through the bedroom) from the bathroom extractor fan. Would you think it would be possible to vent the hob extractor into that?

If it's a duct carrying pipes, then - space permitting - you could put a pipe ( PVC smooth best type ) in there but if you vent straight into a cavity, it will become covered in grease and you will have permanent cooking smells in the flat.

Also, given that the duct runs through the problem bedroom, how about cutting my ventilation holes into the ducting too?

And how do you ensure the kitchen smells are not piped directly into the bedroom ?

 

[bullethead123]

Thanks for your input MW.
The duct is about 8 inches square solely for bathroom vapour extraction.
From what you say, I assume it would it be possible to put "ducting within the ducting". Perhaps 4 inch by 1 inch for the bedroom ventilation and something larger for the cooker extractor? If so what would you suggest? Would this cause the bathroom extraction to become less efficient? As I've already mentioned, the bathroom extractor is on a humidistat, so I presume the fan would just keep going that much longer to compensate.

 

[mointainwalker]

Yes. you need to duct within a duct to extract from several different areas. As you mention, rectangular ducting will be most space efficient but is unfortunately several times the price per metre of round PVC.

The bathroom extraction might become more efficient ( speculation here ) as you will be increasing the speed of the air-flow and (maybe) reducing back-pressure/turbulence . As for your kitchen extraction, you will be governed by the diameter of the pipe at the hood and/or any reducers you fit.

 

[bullethead123]

Thanks again MW.
So I'll use 4"x1" rectangular ducting for the bedroom ventilation. I can use some self tapping screws to secure it to the bottom of the original ducting and cut holes wherever I choose.
A thought has come to mind regarding the cooker extractor. In the kitchen there is a ventilation grille which was originally put in to cover the hole left when the original heating system (gas fired warm air boiler) was removed. Do you think it would be possible to duct the cooker extractor to that or would it be counter productive as that would cut down "normal" ventilation. i.e. when the extractor is not running?
(or would this idea cause cooking smells to be distributed to the flats above?)

 

[mointainwalker]

quote]or would this idea cause cooking smells to be distributed to the flats above?quote]



Can't say as don't know if flues were individual or merged[/quote]