WTF ? Can I insulate it ?

[FRAN1870]

In my Victorian house the ground floor external wall is double skin downstairs, but for reasons unknown the same wall upstairs has had the inner skin removed and replaced with stud work ? There's also an rsj holding up the first floor joists.

I've knocked an inspection hole, there's about a 4inch cavity and the timbers appear in good order.

Anyway I have some small areas of damp up the corner of the room ( this wall ) which appears to be condensation as the brickwork is dry and the plaster in good condition too. It's basically the cold corner of the house.

Anyway I've ordered some trickle vents for the upvc double glazing to help air flow but I have three questions.

1: Can I use expanding foam injection to insulate behind these cavities ? ( of course I'd be guuessing not to miss any areas ).

2: Will the wall being warmer prevent the damp / condensation ?

3: is it pointless only insulating the one wall of the room ?

My daughter has asthma so I'm very conscious of the bedroom conditions.

Any help is greatly appreciated.

 

[cjard]

Upgrading the walls isn't something you can do by half measures, as you'll likely only move the problem somewhere else. Foam doesn't make a good filler either; doesn't expand nearly enough / with any consistency when injected through a hole

Higher surface temperatures inhibit condensation, yes.. Damp on the other hand usually has a cause beyond normal life activities. You need to get to a point where the surface is above 12 degrees c to minimise condensation risk. In terms of upgrade, if you insulate your stud then it's going to need a sensible amount, and it'll need a vapour control layer to stop ,moisture from the house entering the walls

Then you might have to get building control involved because you're renovating a thermal element

 

[endecotp]

Regular expanding foam isn't a fantastic insulator.
It is possible to fill such a gap by pumping polystyrene beads; see e.g. https://pub-prod-sdk.azurewebsites.net/api/file/6d00b4f0-367e-4f88-b6c1-a59300fdae4f . But polystyrene attacks electric cables, which makes it more complicated.
Regarding condensation, first consider where the moisture is coming from. Do you have kitchen and bathroom extractor fans?

 

[FRAN1870]

Thanks both .... we have extractors in the bathroom but not the kitchen ( until we renovate it next year ) This corner is miles away from the kitchen though ? Like on the opposite end of the house.

My thoughts were that some insulation would be better than none ? I'll look into the beads but guess I was looking for a quick non disruptive DIY fix really.

 

[FRAN1870]

I'm also in process of getting some vent tiles put in the roof condensation on roof beams.

 

[cjard]

Just in case the vent tiles don't help; condensation generally comes from somewhere no matter how much provision you make for helping it go on its way. If you find you're persistently dealing with condensation issues, look to the habits of the humans in the house - if he's a compulsive tea makers, and she's obsessed with cooking her own soups 24/7 while drying 3 loads of washing on the rads, and junior spends an hour in the shower with an knackered extractor fan every day, youre looking at pretty moist air entering that cold loft space no matter what the vent proposals are like.. Some lifestyle changes may be required

 

[FRAN1870]

I gave it a suck and see approach and left the insulation but I've started decorating this room and there's a massive problem with condensation in the one corner.

I'm now thinking of ripping off the old plasterboard and insulating the cavity with kingspan or wool and then dropping a vapour layer in before re-boarding .... however I'm so fricking confused by talk of dew points, interstitial condensation and U-Values that I'm actually scared to breath.

I'm not convinced that I can completely seal the cavity so will insulating it just moved the problem to where I can't see it ?

To recap... its a single skin brick wall with a 6 inch studwork cavity / dry lining as the inside skin ( the inner brickwork has been removed ) ????

Can you help please ?

 

[endecotp]

You need to identify the source of the damp air.

 

[FRAN1870]

Would painting the room coupled with cold outside temperature cause the bad condensation .... ?

I may be jumping the gun a little but this room will be my daughters room and I want it to be warm and not affect her asthma

 

[pilsbury]

I had a similar problem in my old house. A 1930s solid wall detached. Also in a external corner of my daughters room. Had a black mold on a 0.25m2 patch.

I too did a bit of research and investigation and came to the conclusion it was condensation. We weren't creating lots of moisture, anything out the norm.

She had a big basket of cuddley toys in front of it to camouflage it initially, but I ended up cutting off the lining paper and repainting and left the corner free of obstructions to aid airflow. Never came back.

 

[FRAN1870]

I had a similar problem in my old house. A 1930s solid wall detached. Also in a external corner of my daughters room. Had a black mold on a 0.25m2 patch.

I too did a bit of research and investigation and came to the conclusion it was condensation. We weren't creating lots of moisture, anything out the norm.

She had a big basket of cuddley toys in front of it to camouflage it initially, but I ended up cutting off the lining paper and repainting and left the corner free of obstructions to aid airflow. Never came back.

Thanks Pilsbury ..... my little one has asthma so mould / humidity control is very important to us too.

I think I'll get the trickle vents in first and see how we go.

I've been reading up on due point an humidity tonight so have a better understanding of it now.

 

[pilsbury]

If you've got any mould give it a bleach wash down and let dry. Then make sure good air flow gets there without obstruction.

I failed to see why my offending corner was any worse than the other external corners.

 

[FRAN1870]

Yes already done that and also some anti mould paint ......