Insulation Question

[outtametree]

I'm fairly sure insulation has been exhaustively covered in the past, however several searches has come up without an answer for me.
So, has anyone tried using a closed cell, fire retardant expanding foam to insulate a GRP boat?
I'm aware that some expanding foams are open cell, so would hold water. Also some are not fire retardant & therefore more toxic than GRP.

 

[superheat6k]

Used class O to insulate an engine box. Can't see any reason not to use it. Various thicknesses available from refrigeration wholesalers - Insultube or armaflex.

 

[outtametree]

Thanks. Looked into the armaflex & will use it in some areas, but there are many spaces I simply can't reach. Hence asking if anyone has experience of using expanding foam.

 

[geem]

Thanks. Looked into the armaflex & will use it in some areas, but there are many spaces I simply can't reach. Hence asking if anyone has experience of using expanding foam.

Expanding foam is a nightmare. It will blow off headlining panels when it expands. Impossible/seriously difficult to remove. Stains everything it touches. Why would you? Lots of better alternatives. You need closed cell foam so it is a natural vapour barrier. Use aluminium self adhesive foil to cover joints in panels otherwise moisture will condense on hull and drip.
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