Aluminum Sheet in Place of 3/4" Plywood?

Did the original marine grade plywood not give satisfactory service and life?

That is, after all, what marine plywood is for.

Nah. It doesn't last long once it's exposed to the elements. I've got the same issue with my boat.

In the OP's case, with a big flat surface, I'd go back with plywood, glue down overlapping sheets of 4' X 8' galvanized sheet to it, and paint it. If you have to use screws through the metal, use them sparingly. The less holes, the better.

After researching the right glue and paint to be used, of course.

Forget indoor/outdoor carpet. Works great for about 4 years, and falls apart........exposing the plywood, which also falls apart.

If price is no object, aluminum would work great. It's also going to blind you in sunlight, and burn your feet.

Don't use aluminum. Period. I'd do this:Pontoon Boat Decking Kits

If you do use aluminum, be sure it's black, diamond plate.

Aluminum Diamond Plate

Composite decking like this would be a forever fix to you deck, albeit a little expensive.

A solid aluminum panel with the stiffness of 3/4 inch ply would be very expensive.

Honeycomb core aluminum panels are made for use in aircraft floors. Very durable, light, very expensive.

There are several honeycomb cores (like Nida-Core) made for marine use that work well with fiberglass facings in polyester resin. You can buy such panels premade, or make them yourself. (Polyester should not be used with wood, if you are concerned about longevity.) There are foam cores made that work well for flooring with fiberglass facings.

Many companies specialize in making panels for marine use that will not rot. These folks could give you an idea of cost for several possibilities.

It is very hard to beat plywood on initial cost. Rolling on a couple coats of epoxy resin, being certain to thoroughly saturate the edges, will preserve it for darn near forever. A layer or two of fiberglass cloth saturated in epoxy resin will make the panel very resistant to abrasion. Although it is common in production boats, polyester resin over wood virtually always fails.

You are VERY ANNOYING AND RUDE!

You should confine your comments to the shameless self-promotion portion of the Commercial section.

I would recommend using plywood but coat the entire surface with fiberglass in several layers. for added strength you could put fiberglass cloth around the edges and make sure they are sealed very well. as suggested you can also embed sand or other grit in the last coat of fiberglass. this should last a long time. I made a small dinghy using 1/4 inch luan plywood and coated it with fiberglass resin, it has held up well. may need a fresh coat every now and then if it gets scuffed or chipped though,

Use Marine Plywood, not CDX, exterior coverings, or any plywood with a weather preservative in it. You cannot put a fiberglass coat over that and make it last for long. The preservatives used prevent the resins from penetrating the wood surface.

Rugs and other coverings keep the surface of the deck wet longer, I would suggest avoiding them. Cover your boat during periods of inactivity with a waterproof covering supporting the center to shed rain and snow. Snow is particularly destructive, it melts and stores moisture on the wood surfaces.

Aluminum WILL burn your feet during summer, coverings will move over it and create trip hazards at best.

After over 50 years of experience in boating, nothing replaces proper maintenance and care, there are no real shortcuts.

If aluminum I envisioned carpeting aluminum. Wouldn't that work? Any materials folks out there that can spec thickness and grade per my OP! Thanks for all the other ideas!!

K-Fry's comment has the reliable answer to your question.

A suitable replacement could be constructed of aluminum, but not at (what most would deem) a reasonable price.

Why Not?

4'x10' sheet of 10 gauge Aluminum Diamond plate costs $172 a sheet. That is at around $2.24/lbs. Last time we purchased it was last November. So Material cost is not an Issue.

Cost would come into play with the shaping and welding, which would be the same cost no matter what metallic material is used. Any shop can take a blue print and work from it. I'm in California, fabrication labor rates run from $45/hr to $85/hr, so get quotes and work them down.

Fabrication would involve cutting the sheets to fit the space it is to be installed, you need flanges either formed so make sure it can be formed, there are different varieties but you have to make sure if it is formed it won't break at the bend or you can weld, but welding costs more. You still need to weld stiffeners inside about 3 feet apart, they can be stitch welded with 1" to 2" long stitches about 12" apart at the most and weld where there is any curvature. The fabrication won't take long, you can probably cut, form and weld within an 8 hour day.

The next cost would be the installing and method for fastening in place. I can't help you there.

We manufacture a lot of catwalk platforms for moving around large machinery complexes.

However, where we install a control room, the floor of the control room is 3/4" plywood.

'....Why Not?...'

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Undoubtedly there are shops that will accept this one off job, and perform all the cutting, bending, deburring, welding and clean up.

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Although everyone cousin knows this guy at a shop who just can't wait to cut you a deal, the cost will be hundred(s) more than what can be constructed by most people at home with minimal tools.

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Even if spending more money gives you a good feeling, the aluminum end product won't. It will be excessively hot at certain times. Despite the diamond plate form, it will be slippery at the wrong times.

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You get to decide early on which of the two next disadvantages you would rather contend with:

1. Prone to dents, twisting, and bowing.

2. Heavier than something made with wood and fiberglass. This option adds even more cost.

This has a lot to do with how the structure is built and the thickness and grade of material.

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Sure, the specific modulus and specific strength of 6160 t6 aluminum far exceeds wood. The amount of time necessary in creating and fabricating a one off piece that realizes an advantage from that in an application like this makes it prohibitively expensive. More specifically, the number of bends, and or welded supports needed to be able to use material thin enough to have a meaningful weight advantage, WITHOUT making something that constantly has a new dent or crinkle in it, in this type off application, makes this material a bad choice.

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For the record, I like working with metals. Actually, a couple decades back, in a former life, I was a welder. For a good portion of that career I worked making custom bike frames, so what I'm saying is merely gas-bag conjecture.

..though you are of course free to interpret what I say however you like. It only takes time and money to learn the lesson firsthand.

Nothing says you can't put a non-skid covering on the plate. You would anyway because aluminum plate would be so bright in the sun that it would be like a spot light shining on you all the time.

Depending on how the Aluminum is fastened, it could be quite thin. Unsupported it will simply bend, but if you make a frame that is rigid and then weld or rivet the aluminum as a diaphragm across the frame there will be some flex but probably acceptable. The sheet used in this way goes into tension as you load it (stand on it). I would guess a 1/8th inch sheet on a suitably strong frame (think 2 inch heavy square tubing on 16 inch centers in a square pattern) would suffice. But this should be done by a mechanical or structural engineer and an experienced fabricator. I would use checker plate to prevent slipping.

Not sure how durable this +(<www.industrialpolymers.com>) would be, but with quartz sand added it may be one solution if sprayed over marine plywood. Aluminum will heat up to the point that the deck may be unlivable in hot weather, and that's when pontoon boats are mostly used) I don't have any connection here, I found it looking for a material I could use to build an over height van top.

Plain plywood, not marine, will hold fiberglass resin well. I have been using this method for some time and have had no problems. I recoat every couple of years and my little dinghy does well. I used luan for the bottom and the sides 3/4 inch pine. I have been experimenting with small, home built boats for some time and coating completely with fiberglass resin(key is the wood must be absolutely dry before coating. with plywood putting fiberglass cloth over the edges also helps prevent them from peeling apart should any moisture manage to penetrate.