# Aluminum Floor Installation



## fish4thriLLs (Apr 18, 2012)

I have been looking into some old posts about this but I still need some new advice.

I have the boat in my signature below. I am hoping to soon add an aluminum floor to go on top of the ribs in the bottom of my boat. I would like for the aluminum sheeting to be around 1/16"(.063") thick. I'm also looking into using either Dibond bonded aluminum(the stuff used for making signs) or solid aluminum sheeting. I am in the process of putting Owens Corning Foamular 1.5" pink foam insulation in between the ribs for support of the aluminum sheet. The ribs are 1.5" tall. The problem is, the foam sticks up slightly above the ribs for some reason.

Will it work out okay for the foam insulation to stick up slightly above the ribs on the bottom of the boat with the aluminum sheet on top of it? I am seriously considering NOT fastening the aluminum sheeting to the ribs but keeping it so I can remove the aluminum sheeting floor for cleaning and keeping the gutter drains cleaned out underneath the Foamular. Is this a bad idea or should I definitely rivet or screw the aluminum sheet down to the ribs, even if the foam sticks up above the ribs? I will be cutting out notches in the sides of the aluminum sheets for the ribs on the side of the boat so the floor fits tight against the sides of the boat.

One more question: If I can't get any aluminum sheeting for a reasonable price, has anyone ever used FRP panels(Fiberglass Reinforced Plastic Panel) for a flooring material(instead of aluminum sheeting) placed over the Foamular foam and ribs? I have a few sheets of the FRP already. I have asked this question before but I guess no one has used the FRP before that had read my post.

Thanks to everyone for your help!


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## jigngrub (Apr 18, 2012)

#1. Don't forget to make a "drainway" down the keel of your boat for proper drainage of bilge water.

#2. Why not frame up a deck out of aluminum angle or squre tubing to allow enough room for your foam and to give your aluminum sheeting the support it needs without relying on the foam to support it? the deck will be flat instead of curved and a lot easier to walk on.


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## fish4thriLLs (Apr 19, 2012)

jigngrub said:


> #1. Don't forget to make a "drainway" down the keel of your boat for proper drainage of bilge water.
> 
> #2. Why not frame up a deck out of aluminum angle or squre tubing to allow enough room for your foam and to give your aluminum sheeting the support it needs without relying on the foam to support it? the deck will be flat instead of curved and a lot easier to walk on.



Thanks for the reply.

#1. My boat has drainage gutters throughout, including in the middle. Thought I would drill a 3/8" hole just in front of the bench seats so water could drain out through the bottom and out the back to the bilge pump. Won't that be enough?

#2. The bottom of my boat is perfectly flat, so there isn't any curve at all.


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## jigngrub (Apr 19, 2012)

Pics always make it better when you post about doing something to a boat.

I'm thinking the foam sticks up a little because it's sitting on the flange of your rib. I'd put the foam in a section and then lay the aluminum and see how I liked it, if it wasn't what I wanted I'd notch out for the flange on each side of the foam... this should make the foam fit flush with the top of the rib.

What are you going to cover the top of the aluminum with?


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## FuzzyGrub (Apr 19, 2012)

I just went through the same process. The flange is raising the foam. I ended up shimming all the ribs vs removing 0.100" from the foam. I also shimmed the middle of the foam, and after recommendation here, cut channels in the foam for some air space and additional space for drainage toward the center. 

I used 0.040" alum, but if you can work with thicker, probably bettter. See my project link below for some pics.


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## jigngrub (Apr 19, 2012)

If you have a router it will cut that 1/16" notch quickly and easily.


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## FuzzyGrub (Apr 19, 2012)

jigngrub said:


> If you have a router it will cut that 1/16" notch quickly and easily.



Yea, I have a router, but not sure I had a bit to go the 1.5" of the flange. I know I didn't have enough dado blades. 

Went with shims to keep a small air space between boat bottom and foam.


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## FuzzyGrub (Apr 19, 2012)

Given you still have your benches (and foam in them), you may be just using the foam to not trip on the ribs. I have seen some other members just lay the foam and then put a rubber liner over it. Easily removable and cleanable. If you need the foam for floatation, the floor will need to be screwed down.


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## BOB350RX (Apr 19, 2012)

in my opinion i would used rubber between the ribs and the sheeting, that would add to the rib and silence and rattles/noise that would transfer to the rest of the boat. as for the sheeting you mentioned im not shure what it even is. good luck with your project


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## BOB350RX (Apr 19, 2012)

on another note i used the tuff coat stuff that cabelas sells to cover the inside of my boat and am very pleased with it, goes on easy and cleans up even eaiser, just an fyi


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## fish4thriLLs (Apr 19, 2012)

jigngrub said:


> Pics always make it better when you post about doing something to a boat.
> 
> I'm thinking the foam sticks up a little because it's sitting on the flange of your rib. I'd put the foam in a section and then lay the aluminum and see how I liked it, if it wasn't what I wanted I'd notch out for the flange on each side of the foam... this should make the foam fit flush with the top of the rib.
> 
> What are you going to cover the top of the aluminum with?



I will try it with the aluminum on it and see how it is.

I have some marine carpet I thought about using to cover the aluminum. Maybe use velcro to secure it to the floor for ease of removal?


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## fish4thriLLs (Apr 19, 2012)

FuzzyGrub said:


> Given you still have your benches (and foam in them), you may be just using the foam to not trip on the ribs. I have seen some other members just lay the foam and then put a rubber liner over it. Easily removable and cleanable. If you need the foam for floatation, the floor will need to be screwed down.



Hhhmmmmm........never thought about using rubber lining over the foam/ribs.

I don't need the foam for flotation, just for floor support mainly.


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## fish4thriLLs (Apr 19, 2012)

BOB350RX said:


> in my opinion i would used rubber between the ribs and the sheeting, that would add to the rib and silence and rattles/noise that would transfer to the rest of the boat. as for the sheeting you mentioned im not shure what it even is. good luck with your project



The sheeting I also mentioned is FRP panel for wall covering.

Here is a link to exactly what it is:

https://www.homedepot.com/buy/lumber-composites/paneling/stabilit/090-in-frp-wall-panel-4-ft-x-8-ft-white-53655.html

Oh yeah, I keep my boat in a mini-barn enclosure, completely out of the weather.


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## PSG-1 (Apr 19, 2012)

I installed an aluminum floor in a 1998 14 foot dura craft, and another floor nearly identical to that one in my jetboat, a 16 foot 1997 Duracraft. 

Both used diamondplate for the floor, and smooth aluminum for the sides.

If you check out my aluma-jet thread, you can see a couple of pics of the floor.

The seams where the floor joined the sides were welded, forming a big tray, basically.

In between all the ribs on the bottom, and on the sides, I used 1 1/2" extruded polystyrene foam board. Once it was all riveted, I didn't have any problems with vibration or the floor buckling.


Your boat has ribs similar to my dura-craft, except, yours don't go to the top of the gunwale, which is how older dura crafts were. in the mid 90's, they brought the ribs to the bottom edge of the inside gunwale, which makes installing a tray type floor really easy.

With yours, the only complication of a tray-type floor would be trying to roll the top edges to the gunwale and attach them...so there's not any gaps from notching out for the ribs, just carry it beyond the top edges.

You'd have to have some type of strip welded along there to be able to rivet to, and you'd have to brake the top edges outward, to flare over that edge. It's definitely do-able, just depends on how technical you want to get.


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## jigngrub (Apr 20, 2012)

fish4thriLLs said:


> The sheeting I also mentioned is FRP panel for wall covering.
> 
> Here is a link to exactly what it is:
> 
> ...



I'd stay away from the FRP for decking, it won't be durable or long lasting enough for foot traffic and weight. It might last for a year or 2 but after that you'll be pulling it up to put down aluminum or plywood.

I forgot to mention earlier that you should fasten your decking down and don't leave it loose, it could blow out of the boat while trailering or on the water. It'll also be noisy and will bend and "cup" if not fastened down. Just fasten it down with aluminum blind (pop) rivets, they're easy to install, cheaper than stainless, have a lower head profile than screws, and are easy to drill out and replace when you want to lift your decking for cleaning and inspection.


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