Expanding foam for the deckhead

Graham_Wright

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Joined
30 Dec 2002
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Location
Gloucestershire
www.mastaclimba.com
Has anyone ever succeeded in sticking expanding foam on a deckhead. After condensation problems through the winter, I thought it would be a good choice for insulation and removal of a condensation haven.

Last night's endeavours led to something reminiscent of the Quatermass experience!
 
These guys manage it - theres even a boat in the piccies :D :D

http://www.spray-insulation.co.uk/DIY.htm

That looks interesting. I bought an aerosol for £8 but is is totally uncontrollable. The foam does not "throw" upwards and falls off in gobs. It was great for filling round the fridge but there it was enclosed.

The two cylinder approach is out of my financial reach!
 
According to a recent article in PBO the aluminised bubble-wrap sold by Homebase, amongst others, works well overhead. Not very cheap but easy to install. We bought one roll but have yet to apply it. Some of the PU foams absorb water, so may not be the answer you are looking for.
 
Single component PU foams use frothing as the primary expansion mechanism. Secondary foaming and curing relies on the reaction of moisture with the MDI/ MDI prepolymer. They are not very reactive, as the catalyst level must be kept low to avoid polymerization in the can ( MDI reacts with itself). They also need an active hydrogen for the MDI/ MDI prepolymer to react with in order to chemically bond to anything; e.g. a damp surface, skin etc.

2 component PU foams are quite different. They have a seperate MDI (usually polymeric MDI) and polyol component. That polyol contains catalysts, surfactants, water (a blowing agent) and often a frothing agent. They are much more reactive than the single component foams, but still benefit from a damp or treated surface for bonding.
 
That looks interesting. I bought an aerosol for £8 but is is totally uncontrollable. The foam does not "throw" upwards and falls off in gobs. It was great for filling round the fridge but there it was enclosed.
Good to hear gravity is still working. ;)
 
We were advised by a professional installer to fix the foam to the GRP with a water based adhesive as that was the point where the cold bridge was likely to occur and we have had no problems with adherence.
 
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