Using flotation foam as deck support...yes or no?

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CalicoJack

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Jan 15, 2023
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LOCATION
Port Orange, Florida
With the price of aluminum these days is the use of flotation foam as a floor support advisable? (only poured in specific places).
I also have 2" insulation foam board that I was planning in placing between the ribs.
 
Not just the foam only, I added the foam inbetween the ribs on my river jon then a piece of 3/8" plywood as a floor over the foam. Was plenty stavile with no flex for my 200 lbs. butt....
 
Not just the foam only, I added the foam inbetween the ribs on my river jon then a piece of 3/8" plywood as a floor over the foam. Was plenty stavile with no flex for my 200 lbs. butt....
Yes, forgot to mention plywood ontop also🙂
 
A customer just brought his boat to me, and he completely filled the floor with foam, and put thin aluminum and carpet over it. Is rock solid. I was impressed, although I would have done it differently.
 
I picked up an Alumacraft 1542 in late January and only had a week before our first spring bass trip so needed a quick temporary floor option. Based on a forum post somewhere I used 1 1/2” foam board for the floor.

I used the closed cell foam board between the ribs to make everything level. For the floor I used the pink (Owens Corning I Think) 1 1/2” foam board - it has a higher compressive strength than the Lowe’s blue version and others. I covered that with vinyl deck cover - just wrapped and stapled I didn’t glue it because I planned to pull it off and put on plywood for permanent floor. I loosely screwed it down in just few spots and hit the water.

Very surprised by how solid it is! I have had 5 or 6 different guys fish with me over the last couple months and did not tell them what the floor was made of. They all raved about how solid the floor is with no flex - couple of them were big boys well over 300#. After a ton of hours on the water the floor is still solid firm and there are no noticeable dents from throwing heavy gear (coolers, anchors, batteries etc.) around.

I have been so impressed I am seriously considering using it for permanent flooring. It added so little weight and was cheap. My plan is to pull off the vinyl, glue a layer of FRP wall board on top, and permanently glue the vinyl deck cover back on. To attach to the ribs I will put strips of flat bar aluminum under the vinyl and screw thru those. The hope is it would be strong enough to keep all the foam in place if needed to keep the boat from sinking if it gets swamped.

I won’t get around to doing anything with it till this fall so I’ll let you know how well it holds up over the next 9 months.
 
With the price of aluminum these days is the use of flotation foam as a floor support advisable? (only poured in specific places).
I also have 2" insulation foam board that I was planning in placing between the ribs.
I used the pink board
Then broke .015” aluminum
To interlock with each other..
Lightweight floor!!!
I’m 250 and it held up just fine.
You will have to rivot floor down every 6”
I think it’s called flashing
I used the white with a painted rough surface..
Floor in my 19’ lowe husky weighed in at 15 lbs
 
I used the pink board
Then broke .015” aluminum
To interlock with each other..
Lightweight floor!!!
I’m 250 and it held up just fine.
You will have to rivot floor down every 6”
I think it’s called flashing
I used the white with a painted rough surface..
Floor in my 19’ lowe husky weighed in at 15 lbs
1679149257553.jpeg
 
H.Depot only has the 1" pink board so I got this 2" from Lowes (the guy said it was closed cell). 20230318_113039.jpg

And I am recycling some aluminum ladders as extra support lol
20230318_115025.jpg
 
If properly supported, most anything will work, the real issues come out when the boat gets wet from being stored outside or being in heavy rain. My boat is a 1992, still in like new condition, as a fair weather boater, I rarely go out in rain, and the previous owner was the same !!
The boat has also been a garage queen so what works well for my boat may not work on a boat that is stored outside. Consider your building materials for where and how your boat is stored....
 
If properly supported, most anything will work, the real issues come out when the boat gets wet from being stored outside or being in heavy rain. My boat is a 1992, still in like new condition, as a fair weather boater, I rarely go out in rain, and the previous owner was the same !!
The boat has also been a garage queen so what works well for my boat may not work on a boat that is stored outside. Consider your building materials for where and how your boat is stored....
Yeah, I'll take it out rinse it off and back in the garage.

Not sure whether to go with outdoor carpet or 'tough coat' for the plywood floor.🤔
 
I picked up an Alumacraft 1542 in late January and only had a week before our first spring bass trip so needed a quick temporary floor option. Based on a forum post somewhere I used 1 1/2” foam board for the floor.

I used the closed cell foam board between the ribs to make everything level. For the floor I used the pink (Owens Corning I Think) 1 1/2” foam board - it has a higher compressive strength than the Lowe’s blue version and others. I covered that with vinyl deck cover - just wrapped and stapled I didn’t glue it because I planned to pull it off and put on plywood for permanent floor. I loosely screwed it down in just few spots and hit the water.

Very surprised by how solid it is! I have had 5 or 6 different guys fish with me over the last couple months and did not tell them what the floor was made of. They all raved about how solid the floor is with no flex - couple of them were big boys well over 300#. After a ton of hours on the water the floor is still solid firm and there are no noticeable dents from throwing heavy gear (coolers, anchors, batteries etc.) around.

I have been so impressed I am seriously considering using it for permanent flooring. It added so little weight and was cheap. My plan is to pull off the vinyl, glue a layer of FRP wall board on top, and permanently glue the vinyl deck cover back on. To attach to the ribs I will put strips of flat bar aluminum under the vinyl and screw thru those. The hope is it would be strong enough to keep all the foam in place if needed to keep the boat from sinking if it gets swamped.

I won’t get around to doing anything with it till this fall so I’ll let you know how well it holds up over the next 9 months.
I just put the same pink foam board in mine while I’m rebuilding. The ribs in my 16/52 are 2” so I used 2” foam board and epoxy treated 15/32 plywood then used snaps to install carpet. This way I can take it apart whenever I want to clean and inspect.
You’re right about it being solid. That was almost 2 months ago and I haven’t made it to the water yet but I’ve been walking and crawling around on it doing other work. My rear bench is hallowed and I built three seats with cushions across the top and had foam left so I put it down and painted some extra plywood I had. Now I have floatation in my storage as well. I wished I would have used vinyl instead of marine carpet but I had the carpet on had I had bought cheap.
 
Yeah, I'll take it out rinse it off and back in the garage.

Not sure whether to go with outdoor carpet or 'tough coat' for the plywood floor.🤔
I used marine carpet in my new floor and already don’t like it. I’ve also been wiring etc. for the past few months and it gets pieces of wire in it and other debris that my big shop vac can’t get out. Wished I’d have used vinyl or anything I could just rinse off.
 

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