Which of these don't need skimming?
- Thread starter MrsRenovator
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- window reveal
As I said before.... This isn't so much of a cold bridge, more like a cold express super highway!
Oh. Id better get it covered back up quickly then. 
12 months later:
I filled every gap, every dent, every hole in the lintel with expanding foam.
Then we used 10mm aerogel blanket on the 3 reveals, covered with foil vapour barrier then 6mm mgo board.
I had room for 30mm of insulation under the window boards so used xps and layered it to make it level. Then bought 3 oak floor boards for the deep window sills, and cut off the tongue on the front edge.
I dry lined and then painted.
When the sun shines you can see a slight chequered appearance on the reveals due to the texture of the boards whereas the PB walls are smoother. Maybe a thin scrape of easyfill all over the boards would have covered it better.
But no condensation and no black dots of mould! Quite a transformation to the feel of the room altogether. Success!
I filled every gap, every dent, every hole in the lintel with expanding foam.
Then we used 10mm aerogel blanket on the 3 reveals, covered with foil vapour barrier then 6mm mgo board.
I had room for 30mm of insulation under the window boards so used xps and layered it to make it level. Then bought 3 oak floor boards for the deep window sills, and cut off the tongue on the front edge.
I dry lined and then painted.
When the sun shines you can see a slight chequered appearance on the reveals due to the texture of the boards whereas the PB walls are smoother. Maybe a thin scrape of easyfill all over the boards would have covered it better.
But no condensation and no black dots of mould! Quite a transformation to the feel of the room altogether. Success!
@MrsRenovator Could you add some pictures of the finished window? Im trying to work out how to plaster the MgO board at the moment, and also work out how to deal with windows, so very relevant!
Thanks
Thanks
Well hello!
That was nearly 2 years ago, and what a difference it has made. No drops of condensation, no cold air circulation, no mould!
Here are some photos. Not sure they'll be much help though. Maybe they will encourage you to do a better finish than mine! I used paper tape with the metal strips attached on the outer corners and dry lined. Obviously they are not really strong enough for wall corners generally, but they're ok for us.
You can see on the photos how near I got to the window frame. Maybe you can also make out that I only dry lined and feathered the edges and didn't plaster (with easyfill or similar) the whole board. I printed with an acrylic primer/undercoat and then just painted on top.
That was nearly 2 years ago, and what a difference it has made. No drops of condensation, no cold air circulation, no mould!
Here are some photos. Not sure they'll be much help though. Maybe they will encourage you to do a better finish than mine! I used paper tape with the metal strips attached on the outer corners and dry lined. Obviously they are not really strong enough for wall corners generally, but they're ok for us.
You can see on the photos how near I got to the window frame. Maybe you can also make out that I only dry lined and feathered the edges and didn't plaster (with easyfill or similar) the whole board. I printed with an acrylic primer/undercoat and then just painted on top.
Since then, we have done a bathroom renovation. One wall had a stud wall built to accommodate pipework so that was easy to insulate. But this time I did the reveals with marmox. Can't rate it highly enough. Would definitely use it again. Although more expensive I suppose, it meant we could insulate and board in one. And used the same boards for tiling as for skimming the walls so less waste.
The plasterer wasn't impressed. Because they don't absorb water at all, the skim takes ages to go off. So instead of a 10/20 min 'keep your eye on it' he had to wait for an hour or two. Didn't bother me though!
I used 20mm marmox where possible, and 12.5mm where the reveals were just too tight. It's great! It's the future! You just have to hack off as much plaster on the reveals as you can to get the thickest insulation possible.
The plasterer wasn't impressed. Because they don't absorb water at all, the skim takes ages to go off. So instead of a 10/20 min 'keep your eye on it' he had to wait for an hour or two. Didn't bother me though!
I used 20mm marmox where possible, and 12.5mm where the reveals were just too tight. It's great! It's the future! You just have to hack off as much plaster on the reveals as you can to get the thickest insulation possible.
Thanks very much and apologies for digging up an old thread but I always think its useful to see the output! Hard to see from those pictures but looks good to me! I assume by metal strips on the corners you mean metal corner bead?
Interesting, I know Aerogel is now available in a wallboard (WL) format that should just cut and stick to the walls (which is what I am planning to use), though then needs a plaster coat for a nice finish really (and too thin for tiling, though they do a tiling board too). I will have to check out the relative benefits of marmox in comparison, did you just insta-stik foam it into place?
Thanks again!
Interesting, I know Aerogel is now available in a wallboard (WL) format that should just cut and stick to the walls (which is what I am planning to use), though then needs a plaster coat for a nice finish really (and too thin for tiling, though they do a tiling board too). I will have to check out the relative benefits of marmox in comparison, did you just insta-stik foam it into place?
Thanks again!
No probs
No, on the external corners I just used reinforced paper corner tape. Eek.
The aerogel is weird stuff. I don't think I'd use it again. Very very dusty. And when you try to drill through it the drill just snags and pulls all the insulation out! We had very uneven walls so we drilled/screwed and then slightly backfilled with expanding foam where needed.
Not sure you can instastick marmox, might have to check their webpage. We drilled and plugged the marmox, then plastic washer and screw.
There must be thousands of houses like mine where there isn't a cavity and external insulation isn't possible. So we have to be inventive with internal insulation. I've done a few experiments in various rooms on external walls and while it'll never be like a passivhaus it has helped enormously.
No, on the external corners I just used reinforced paper corner tape. Eek.
The aerogel is weird stuff. I don't think I'd use it again. Very very dusty. And when you try to drill through it the drill just snags and pulls all the insulation out! We had very uneven walls so we drilled/screwed and then slightly backfilled with expanding foam where needed.
Not sure you can instastick marmox, might have to check their webpage. We drilled and plugged the marmox, then plastic washer and screw.
There must be thousands of houses like mine where there isn't a cavity and external insulation isn't possible. So we have to be inventive with internal insulation. I've done a few experiments in various rooms on external walls and while it'll never be like a passivhaus it has helped enormously.
100% agree, Im just starting the journey now (shame as I wish I had done it when I did the full renovation 8 years ago, but it wasnt much of a thing then).
Agreed its pretty weird stuff, but I found it was actually very easy to cut with a decent knife (and in fact you could score the 3mm MgO boards a few times and it cracked perfectly without making any dust). If there is something more sturdy then I'll happily swap as I dont look forward to drilling into it for mounting cupboards etc! Im definitely looking forward to another cold spell and testing with a heat camera to see the improvement!
Agreed its pretty weird stuff, but I found it was actually very easy to cut with a decent knife (and in fact you could score the 3mm MgO boards a few times and it cracked perfectly without making any dust). If there is something more sturdy then I'll happily swap as I dont look forward to drilling into it for mounting cupboards etc! Im definitely looking forward to another cold spell and testing with a heat camera to see the improvement!
Oh my goodness. Screwing cupboards through aerogel would be horrendous.
Just in case it's of interest, here is a picture of my first experiment. Approx 6 or 7 years ago. I had plenty of room here.
Spare room, the external wall behind the wardrobe used to get black mould. Had to keep bleaching it clean. Furniture was all 8" off the wall for circulation. And it made the house soooo cold. In the end we just closed the door and let it all go mouldy till the spring.
The plaster was in good condition so after bleaching it clean and scraping any loose paint off I instasticked 100mm of foil backed insulation board to the wall and meticulously sealed all joints, damage and the edges with foil tape to ensure no warm air could reach the cold wall behind. Then I stuck the plasterboard up, dry lined, painted and put the old skirting board back on.
The difference is miraculous. We don't heat the room unless guests are there, but we leave the door open now. No draw of cold/warm air at all and probably never goes below 13° in there I should think. No mould, no smelly clothes, no musty mattress.
And as you can see from the photo, you wouldn't know to look at it.
Just in case it's of interest, here is a picture of my first experiment. Approx 6 or 7 years ago. I had plenty of room here.
Spare room, the external wall behind the wardrobe used to get black mould. Had to keep bleaching it clean. Furniture was all 8" off the wall for circulation. And it made the house soooo cold. In the end we just closed the door and let it all go mouldy till the spring.
The plaster was in good condition so after bleaching it clean and scraping any loose paint off I instasticked 100mm of foil backed insulation board to the wall and meticulously sealed all joints, damage and the edges with foil tape to ensure no warm air could reach the cold wall behind. Then I stuck the plasterboard up, dry lined, painted and put the old skirting board back on.
The difference is miraculous. We don't heat the room unless guests are there, but we leave the door open now. No draw of cold/warm air at all and probably never goes below 13° in there I should think. No mould, no smelly clothes, no musty mattress.
And as you can see from the photo, you wouldn't know to look at it.
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Hmm, I may live to regret that then, will try and minimise the number of screws through it since mostly it will be like a wardrobe with a structural back plate that actually supports the weight.... (so just needs securing from falling and straightening up)
And presumably you did that insulation behind the skirting board all the way to the floorboards? Or did you leave a 10mm gap?
And presumably you did that insulation behind the skirting board all the way to the floorboards? Or did you leave a 10mm gap?