thoughts on using spray foam inside hulls

I'm in the process of building a boat and would like some expert advise on the pros and cons of using spray foam on the inside of the hull and cabin superstructure...besides the obvious flotation i'm thinking it would provide nice insulation to extend the boating season up here in the north country...any thoughts you might have on this would be greatly appreciated..

 

Over time foam absorbs and traps moisture.

 

It depends on the foam and the substrate it's going on. Typical 2 pound spray on foams come in lousy and not quite so lousy formulations. If you want the good stuff, you'll have to pay for it and it's not easy to apply well (full personal protection). What is the foam going on?

 

Big problem is foam burns .

While you might find some that is fire "resistant" (burns slower) the entire foam area will need some sort of covering.

FF

 

Very common here to use spray foam on the inside of the hull/superstructure of steel inland waterways boats, like canal boats. I'd go so far as to say it's almost universally used. As mentioned above, you need to use the right stuff, which either means gettting the proper gear yourself or getting a team in to do it, as they'll have the right protective gear and spray equipment. AFAIK the right type of foam is both long lived and not a particularly great fire risk. See here: http://www.spray-insulation.co.uk/narrow_boat_insulation.htm

 

The foam should be kept above the bilge line. It shouldn't be located where it will be subjected to constant moisture. It is a "life jacket" for the boat and like the life jacket you wear it should be kept dry until needed.

Just my amateur's opinion.

 

Thanks for your quick responses. I checked out the web site Jeremy reccommended. Then dug a little deeper in this forum and found many discussions on the topic of foam in boats. So let's but this thread to bed until I come up with a question that hasn't already been answered. Many thanks for your responses.