Expanding foam as insulation?

[john4703]

I’ve stripped off the old wall covering on the outside wall of my bathroom. I was surprised to find that the lower part of the wall was a sheet of gyproc 1200 high across the width of the room 1500. There were no fixings behind it except at the ends.

I’ve stripped that off and all the old lath and plaster and will fix supports and cover it in Hardibacker for tiling.

I’m wondering if spraying the wall with expanding foam would be a good way of insulating it and making the room a bit easier to heat. Is expanding foam a good insulation?

 

[RonnyRaygun]

I’ve stripped off the old wall covering on the outside wall of my bathroom. I was surprised to find that the lower part of the wall was a sheet of gyproc 1200 high across the width of the room 1500. There were no fixings behind it except at the ends.

I’ve stripped that off and all the old lath and plaster and will fix supports and cover it in Hardibacker for tiling.

I’m wondering if spraying the wall with expanding foam would be a good way of insulating it and making the room a bit easier to heat. Is expanding foam a good insulation?

Seeing as spray on foam is a common type of insulation, I would imagine that there will be tangible benefits to any expanding foam as insulation. http://www.thegreenage.co.uk/spray-foam-insulation-faq/. But why not just get the proper stuff?

 

[john4703]

I was thinking that expanding foam will seal any drafts, fill the very uneven space and never slip down

 

[theprinceofdarkness]

If you are talking about the rattle cans of foam, I think they are unsuitable. When squirted at a vertical surface for the first 5 seconds or so they are very liquid, so the foam will run down. After 5 seconds more the foam will start to foam and expand after 30 seconds or so the expanded foam will then start to harden. it will continue to expand and harden for 12 hours. In this last stage it exerts a large pressure, so if you try to keep it in place with a temporary shuttering, it will tend to bow it. It seems that in the liquid state its not sticky (else it would not run down) its during the 30 second stage that it gets really sticky, but by then its laying in a pool on the floor.
Frank

 

[leewallbank]

Pink grip dry fix. It's low expansion, spray it on the back of the plasterboard, wait 2 mins and fit.