Insulating a 1970's Concrete construction flat

Insulating a 1970's Concrete construction flat

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lewisf182

Original Poster:

2,084 posts

187 months

Monday 26th January 2015
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Hi,

After a lot of research on the internet I'm still none the wiser on what exactly to do about insulating my recently purchased flat and fixing the condensation issues.

Basically, I think a suspended ceilling and insulation would do the job of making the flat much warmer and would get rid of the condensation and damp problems i'm having caused by the cold ceiling meeting the warm air in the flat.
The flat itself has a lot of vents and fans which should get rid of any condensation problems but it just doesn't work properly.

So, just thought I'd ask here if people had similar problems/experiences and how they fixed it? or if any professionals here what would you advise?

Due to it being solid concrete I'd have to move all pipes and plug sockets etc which is fine. Just want to create a blank canvas and make the flat warmer. I'd probably look at trying to install throughout the whole flat, which means new kitchen and bathroom etc.

Any advice much appreciated.

hoppo4.2

1,531 posts

185 months

Tuesday 27th January 2015
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if your going to gut the place then I guess the best option would be to line it with insulation backed plaster board then have it all skimmed.

lewisf182

Original Poster:

2,084 posts

187 months

Saturday 31st January 2015
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Yeah thats my thoughts.
Just wondered wether that would definitely solve it and if there were other options about so thanks

steveo3002

10,494 posts

173 months

Sunday 1st February 2015
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not a concrete flat but we had a single skin wall in our kitchen , i used the insualted platerboard and its worked out well , iirc its about 25mm thick but i think you can go thicker if need be

lewisf182

Original Poster:

2,084 posts

187 months

Monday 2nd February 2015
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Did you have damp/ Condensation problems prior to that? or purely to add insulation for warmth?

Blue Oval84

5,276 posts

160 months

Monday 2nd February 2015
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Is the flat a top floor one then?

lewisf182

Original Poster:

2,084 posts

187 months

Tuesday 3rd February 2015
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Yes top floor, with most of the external walls open to the elements too. so end of block & top floor if that makes sense.

GuinnessMK

1,608 posts

221 months

Tuesday 3rd February 2015
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You need to carefully consider where to install the vapour control layer. At the moment, the hot humid air meets the cold concrete and the water condenses on there. If you add insulation, you separate the hot air from the cold structure (which is good). However you will still have moisture issues somewhere, even if you can't see them. So it might be at the window heads or reveals, or it may form on the walls behind your insulation, running down to the floor (where it will either be a problem for you, if you don't insulate your floor, or your neighbour below.

If it's a full refurbishment, then you could start from first principles, building up air tightness (and controlled ventilation), insulation and vapour control.

Missingbadly

198 posts

110 months

Tuesday 3rd February 2015
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Insulated wall lining - could be a plasterboard composite but must have a vapour barrier. Not breathable but a barrier. Good extract vents in wet areas - cooker hood/bathroom. Work extracts off lights not humidistats so they definitely come on. You'll need pvc d/g windows. If the ceiling is concrete (some are) use the same as the wall lining or if a top floor flat and you can get above insulate from there. Extract all tumble drier moisture direct. Don't air dry washing. Don't cook rice all day. Wait until it all dries out and hey presto you'll be fine.
Oh and tricked vents to windows to maintain air flow and an effective heating system.
You've got to get the lot up to speed but it's no biggie once you're into it. Wall lining = new skitings = buggering about with electrics and maybe architraves.

TonyRPH

12,963 posts

167 months

Tuesday 3rd February 2015
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OP - apologies for hijacking your thread.

I live in a 1960's poured concrete Wimpey home. We're lucky enough not to have any damp issues, however if we leave anything pushed up against an outside wall, within days there will be a black mildew / mould patch.

So my question is - the suggestions are that the OP insulates the inside with battens and plasterboard - but won't mildew form behind the plasterboard?

Because we have looked at doing something similar (simply for insulation purposes), but I've been led to believe this will create more problems than is solves.

wolfracesonic

6,941 posts

126 months

Tuesday 3rd February 2015
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OP and TonyRPH, if you do insulate the walls use something like these, thermal laminate they have a high performance insulation and a vapour barrier built in, so no moisture can pass through them to condense on the cold, outside wall, which can encourage mold/further damp problems. Interstitial condensation is the posh term, apparently;)

Missingbadly

198 posts

110 months

Tuesday 3rd February 2015
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TonyRPH said:
OP - apologies for hijacking your thread.

I live in a 1960's poured concrete Wimpey home. We're lucky enough not to have any damp issues, however if we leave anything pushed up against an outside wall, within days there will be a black mildew / mould patch.

So my question is - the suggestions are that the OP insulates the inside with battens and plasterboard - but won't mildew form behind the plasterboard?

Because we have looked at doing something similar (simply for insulation purposes), but I've been led to believe this will create more problems than is solves.
Yep you've got a bit of condensation. I doubt it's cold bridging as it's just behind furniture. You need to ventilate, turn the heating up a notch and avoid over generation of water vapour by all the usual suspects. Keep that up for a couple of weeks. Also wipe the areas down with some diluted bleach to kill the mould.
If it comes back you're into maybe increasing extract vent sizes etc.

To OP: Mildew won't reappear after initial drying out of insulated linings if the other things are in place.

To all: Condensation risk is a fine balance of heating (insulation) and ventilation versus water vapour generation.

lewisf182

Original Poster:

2,084 posts

187 months

Wednesday 4th February 2015
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Ok, thanks for the advice. Feel like I know what I need to do now really, only issue is finding the £.