Condensation between outside wall and sofa/cupboards

andre_xs

Colder weather, and we're back to our condensation / mould problems:
In our living room, our sofa and a couple of shelfs are against an outside wall, and we get condensation and mould there. It's a mid-1950s build and has cavity insulation done (by previous owner). It's a terraced house, and the wall is facing outside but to a walk-through corridor to the gardens, i.e. it is roofed by the first floor and doesn't get any rain - walls seem to be dry (condensation is mainly only 1m height). Last year, I've done already a moisture proof sealing of the floor and have a waterproof membrane going from behind the skirting boards roughly 50cm into the floor of the room.

Here are my thoughts, I'd be grateful for comments (costs, DIY feasiblity, alternatives). Since we are on a tight budget, we'd like to get as cheap solutions as possible, but they should work.

1. Install fans (e.g. USB ones) which are working through the night where most condensation seems to appear. Place them so that the air behind sofa/cupboard circulates. (at night, room temperature is set to 19 degree)
2. Set up an air dehumidifier for the night (we have a 'proper' one, would be too noisy for the day). But I'm afraid that this wouldn't make much difference behind sofa etc.
3. Put insulating wall-paper on the affected wall / spaces (possibly just behind cupboards etc)
4. Install some outside insulation (needs to be cheap, so possibly just some rockwool held to the wall by netting. The wall is roofed, so rain is not an issue)
5. Try to get some warmth there, e.g. by electric floor heating (just a strip running along the wall, running on a low setting during the night). Should also naturally increase circulation. I presume could be installed in DIY?
6. Try to get some warmth there, e.g. by just having a radiator pipe (copper or maybe even just plastic) running in a loop (radiators are only on the inside wall, piping is above the wall). However, heating rarely runs during the night, but would warm up during the day. Not sure I could do it myself, possibly using these plastic quick fittings.
7. Getting smarter thermostats and keep just the living room warmer during the night
All of the above :eek: :rotfl:

naf123

andre_xs wrote: »

Colder weather, and we're back to our condensation / mould problems:
In our living room, our sofa and a couple of shelfs are against an outside wall, and we get condensation and mould there. It's a mid-1950s build and has cavity insulation done (by previous owner). It's a terraced house, and the wall is facing outside but to a walk-through corridor to the gardens, i.e. it is roofed by the first floor and doesn't get any rain - walls seem to be dry (condensation is mainly only 1m height). Last year, I've done already a moisture proof sealing of the floor and have a waterproof membrane going from behind the skirting boards roughly 50cm into the floor of the room.

Here are my thoughts, I'd be grateful for comments (costs, DIY feasiblity, alternatives). Since we are on a tight budget, we'd like to get as cheap solutions as possible, but they should work.

1. Install fans (e.g. USB ones) which are working through the night where most condensation seems to appear. Place them so that the air behind sofa/cupboard circulates. (at night, room temperature is set to 19 degree)
2. Set up an air dehumidifier for the night (we have a 'proper' one, would be too noisy for the day). But I'm afraid that this wouldn't make much difference behind sofa etc.
3. Put insulating wall-paper on the affected wall / spaces (possibly just behind cupboards etc)
4. Install some outside insulation (needs to be cheap, so possibly just some rockwool held to the wall by netting. The wall is roofed, so rain is not an issue)
5. Try to get some warmth there, e.g. by electric floor heating (just a strip running along the wall, running on a low setting during the night). Should also naturally increase circulation. I presume could be installed in DIY?
6. Try to get some warmth there, e.g. by just having a radiator pipe (copper or maybe even just plastic) running in a loop (radiators are only on the inside wall, piping is above the wall). However, heating rarely runs during the night, but would warm up during the day. Not sure I could do it myself, possibly using these plastic quick fittings.
7. Getting smarter thermostats and keep just the living room warmer during the night
All of the above :eek: :rotfl:

you can place this

https://www.lakeland.co.uk/24627/Lakeland-Non-Spill-Moisture-Trap

FreeBear

Are you sure it is a cavity wall ?

I know of a short row of terraces (post war) that only has a single skin wall along the passage way.

Insulating effectively either internally or externally can not be done for a couple of bob. Thermal wallpaper will make a marginal improvement, but you need to do the whole wall. Rockwool/fibreglass externally just covered with netting isn't going to work - It will get damp and quickly become ineffective.

I would suggest one of the following.

1) Line the wall internally with 50mm to 75mm of Kingspan/Celotex PUR boards, cover with plasterboard and skim - Do a search for "warm batten" to see how it is done.

2) Insulate externally with wood wool boards and put a layer of render over the top to limit damage. You could probably get away with 50mm here.

I'd be tempted to go with external insulation and do the "roof " at the same time - This would provide some valuable insulation for the room over the passage.

andre_xs

No, I'm not sure that it's a cavity wall, good point, would explain a lot. I just assumed it...
(On second thought, you are probably right. With a cavity wall we should have much better noise protection from neighbours, and it seems a bit unlikely that they've done only the first-floor bit as cavity wall...)

Well, the thermal wallpaper was not meant to improve insulation greatly, but merely do reduce condensation at the critical points where there's no sufficient air circulation - to warm up the wall a bit. At other places of this wall (e.g. at the upper corners), we don't have an issue.

Your suggestion sounds really good, but I think it'd be too expensive right now...

We might go for 2 - 3 low wattage tube heaters (another thing I came across) in combination with some small USB fans. During the night, we can alternate (using two electronic timers) between let's say 45min tube heater, 45 min fan, 45 min tube heater, etc. Or just have the tube heaters run through the night, if they're low wattage they won't cost much, but even the small amount of warmth should be enough to start some circulation and get rid of any condensation...

Fire_Fox

Condensation is an issue with lifestyle, home ventilation and heating.

Do not underestimate the many litres of water a 'normal'/ modern family produces each day, especially if home day and night (breathing, showering/ bathing, cooking with uncovered pans, laundry esp. air drying). Addressing this may even save you money! Stats are online if you want to estimate your your family's ouput.

Why is only this section of this wall suffering? Move furniture to allow air to circulate. Heat alone just helps the air hold more water ... But there are limits!

Ventilation (opening doors/ windows, using kitchen and bathroom extractors for long enough, venting tumble dryer properly, installing other systems such as PIV) or dehumidifier regularly obviously reduces the water in the home.

andre_xs

@FireFox
We already do quite a bit, but due to the size and layout of the living room, we can't move the furniture or set it up differently. I think it is only in that area because there is just not enough circulation, even with regular opening windows/patio door. For instance, the (corner)sofa is of a style that it goes basically to the floor which prevents circulation behind it.

Lorian

what's the humidity % in there?

Fire_Fox

andre_xs wrote: »

@FireFox
We already do quite a bit, but due to the size and layout of the living room, we can't move the furniture or set it up differently. I think it is only in that area because there is just not enough circulation, even with regular opening windows/patio door. For instance, the (corner)sofa is of a style that it goes basically to the floor which prevents circulation behind it.

Try experimenting pulling the sofa out a couple of inches for a week, then a couple more for a week. You will see what you can live with, as well as what works or does not work! If it works BUT it is hell to live with, focus on ventilating the area in other ways.

Otherwise pulling the sofa right out each night when you use the dehumidifier. Every experiment teaches you something about the problem, if it does not cost much/ it is worth a try. If it is ineffective, then hit the insulation/ heating options.

I went nuts with lifestyle change - everything except stopping breathing! My condensation issue is partly metal-framed windows ('thermal bridge') and extractors/ ducting that was designed/ installed by muppets such that it would never be useful. The earlier experiments helped me look creatively for solutions.