Flotation foam under deck

[rottenray6402]

I'm sure this question has come up many times but I seem to be having a problem with the new search feature since the format has been changed. Anyhow, I am replacing the plywood deck in my 92 Crestliner and am getting ready to lift the plywood. I found in the rear area foam that looks just like great stuff insulation so I anticipate finding the same stuff under the plywood. I know from reading this forum that some foam will soak up water and become saturated over time. My question is : will great stuff work for floatation, if the existing foam looks good should I leave it alone? If it is bad and great stuff won't work what should I use? Thanks! ???

 

[imported_John_Galt]

Re: Flotation foam under deck

I am about to do mine over again. I pulled the deck to repair rot and found my foam was actually a sponge.

I will be using :Faom-It" a two-part urethane foam"

There are other less expensive foams too. Look here: http://www.jgreer.com/Foam Page.htm. This product is CG approved.

 

[sdunt]

Re: Flotation foam under deck

There have been roaring debates about foam, whether to use it or not. Some people think that the foam only contributes to rotting out the floor and refuse to put it in their boats. Others swear by the foam and say that it helps make the boat much more solid.

what every you do, don't use 'great stuff' from the home depot, that stuff is not a 'closed cell' foam and it will soak up water like a sponge. You also might consider doing a 'core sample' of your foam. Many have found that its wet on the bottom when the top looks good.

In my case do to costs and very limited area to fill I used foam building panels: http://www.owenscorning.com/around/insulation/products/foamular.asp

We use these in buildings below ground and I know they don't soak up water.

Others have tried empty pop bottles, etc with mixed results. I even read about a guy who used packaging p-nuts in his sail boat.

Its up to you, but if you do foam the concencious is to use 2 part pourable foam the 2 lbs type

 

[dmarkvid2]

Re: Flotation foam under deck

I've said this in many threads, and like sdunt said, one thing you can do is to buy the pink house construction styro foam at home depot. It comes in 8' lenths, and 2" thick. It won't retain water, and will not rot. Ex: If you have a space that is 8" deep between stringers, you can epoxy 4 - 2" piecies together making the total thickness 8", and then cut, and fit it to the shape and size you need to fill. it takes time, but works well, and its alot cheaper than the 2 part chem. foam.

 

[rottenray6402]

Re: Flotation foam under deck

Thank you all for your advice, I thought I had read in the forum that great stuff would turn into a giant sponge. I never thought of using the pink rigid type foam. I think that is what I will do. I appreciate the help! 8)

 

[ted655]

Re: Flotation foam under deck

Polyurethane foam (Great Stuff & other brand names) comes in different densitys(flotation ratings). It all will "sponge". Polystyrene does not absorb water, but doesn't come in a can. Blue, pink, white, it all floats. Brst way to Google it is to type "billits" in the search line. Here is a "new" product that I have done no tests on yet.
Dap-tex. Not as nasty to clean off your hands.
My advice is use styrene where you can & use urethane IF it has a good chance of never getting wet for any length of time, THEN keep an eye on it. It will encourage rot & add weight. Really good stuff can be boyght at FgCI.
http://www.fgci.com/