# which type of plywood for decking?



## wcoastwhacker (Aug 6, 2011)

so ive done some searching on this site and i've found several answers to this question and want some clarity...

i want to install a deck in my boat (pics to come) and dont know what kind of plywood/wood to use. some say STRICTLY marine grade with coats of waterproof sealant, and others say exterior plywood with coating will work. will either work? which is the cheaper way to go and where can i find this type of plywood/2x4's whatever i need? this is my first project so give noob details! 

Thank you!


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## SVOMike86 (Aug 6, 2011)

Marine Ply is exceptionally expensive-anywhere between $75-150 a sheet. You can use anything you want really, but DO NOT use pressure treated. Corrodes aluminum. I used stuff from Home Depot called "Home Advantage". It was cheap, like $20 a sheet, perfectly straight, and apparently will not absorb water at all. I still coated it with spar urethane, but its better to do it right the first time. If I could have afforded it, I would have used Marine Ply. Use the search function at the top of the screen and I guarantee every question you have can be answered quickly by people that have already answered them...


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## wcoastwhacker (Aug 6, 2011)

Currently I don't have the funds for marine plywood at that price so ill go ahead with the ply yo recommended along with the sealant. does th same go with 2x4's? Anythin will work as long as it's sealed?


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## SVOMike86 (Aug 6, 2011)

Pretty much, just make sure its not pressure treated. Do some planning to get your bracing as efficient as you can (meaning as little of it as you can). 2X4's get HEAVY and take up a lot of space... If you have any metal scrap yards around you, go check them out for scrap aluminum angle. If you can get aluminum for fairly cheap, thats the way to go, its lighter than wood, wont rot, and is stronger. Just rivet it together.


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## jigngrub (Aug 6, 2011)

If you're going on the cheap, use the exterior grade plywood (not that chip board crap). Seal the top side and edges only (you want the bottom side to be able to breathe).

You'll save a considerable amount of weight (important with small boats) if you'll do your framing with aluminum angle instead of 2x4s. You can buy the angle cheap at scrap yards and recycling centers. Use pop rivets to put your framing together with.

Installing vinyl instead of carpet will be more water repellent than carpet and will make your decking last longer.

Fastening your decking down through your vinyl or carpet will come in handy if you ever need to take your decking off to work on your boat.

Installing floatation foam under your decking is a good idea for safety purposes, you can use the pink or blue polystyrene sheets they sell at home depot.


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## Captain Ahab (Aug 6, 2011)

SVOMike86 said:


> Marine Ply is exceptionally expensive-anywhere between $75-150 a sheet. You can use anything you want really, but DO NOT use pressure treated. Corrodes aluminum. I used stuff from Home Depot called "Home Advantage". It was cheap, like $20 a sheet, perfectly straight, and apparently will not absorb water at all. I still coated it with spar urethane, but its better to do it right the first time. If I could have afforded it, I would have used Marine Ply. Use the search function at the top of the screen and I guarantee every question you have can be answered quickly by people that have already answered them...




Right on - I did not use marine grade and it is working just fine


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## wcoastwhacker (Aug 6, 2011)

thanks for the help guys! i plan on putting rubber drainage matting directly on the aluminum floor and using ply for the front and rear decking. instead of carpeting the decks i was thinking of a non skid paint directly on the wood. any recommendations?


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## SVOMike86 (Aug 6, 2011)

Your boat more than likely has chines, which are the channels that run front to back. They serve pretty well for drainage. You shouldnt need to put any rubber matting on them, better bet is to put some floatation foam under deck like Jigngrub said. Better safe than sorry...


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## reedjj (Aug 7, 2011)

wcoastwhacker said:


> thanks for the help guys! i plan on putting rubber drainage matting directly on the aluminum floor and using ply for the front and rear decking. instead of carpeting the decks i was thinking of a non skid paint directly on the wood. any recommendations?



I used Tuff Coat. Its a rubberized non skid that comes in a few different colors, I used Tan. It was a pain in the butt, and requres a primer coat. I do like the results but if I had to do it over again. I wouldn't! I would take it to the LineX place and let them do it. After I bought tape, rollers, mineral spirits, drop cloth, paint mixer, applicators I was in for what it would have cost to have lineX do it. Here is the boat I used the tuff coat on... https://www.tinboats.net/forum/viewtopic.php?f=3&t=20508

On my last boat I did the floors and front deck in exterior plywood with 3 coats of spar urethane. I used the Minwax brand Helmsman spar urethane in a spray can. I then painted the floor and decks with green Camo rustoleum and it was not slippery and held up fine. If it gets scratched or something you just spot spray it with more spray paint. You can see and read how I did it here....https://www.tinboats.net/forum/viewtopic.php?f=21&t=17299&hilit=swamp+sled


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## wcoastwhacker (Aug 7, 2011)

i just got back from home depot and purchased 3/4" red oak plywood for the deck along with a quart of helsman spar urethane for coating. will this plywood work well?


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## jigngrub (Aug 7, 2011)

wcoastwhacker said:


> i just got back from home depot and purchased 3/4" red oak plywood for the deck along with a quart of helsman spar urethane for coating. will this plywood work well?



No it won't, that's an interior grade plywood and doesn't have the water resistant glue like the exterior grade.


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## wcoastwhacker (Aug 7, 2011)

sounds like i'll be returning it tomorrow then....so white oak is the way to go?


i just called home depot and they do not carry white oak plywood.any recommendations?


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## MoHops (Aug 7, 2011)

Go to Home Depot and tell them you want 3/4 CDX plywood. It will be pine or fir. More than likely fir. The CD stands for C grade on one side and D side on another. The D side will be the worst side with unfilled knots so I would put that side down. The X stands for exterior grade and has a different adhesive than interior panels. Oh and a lot of plywoods have gone to 32nds for measurement. So 23/32 CDX is more than likely what you will find. Should be on the racks in front by the framing lumber.
If you still are having problems, go to a local lumberyard, not a big box store. Local lumberyards typically have a little more experienced help. Oh and most of them don't charge you to cut plywood for you if you ask!!! (Still can't believe how much the box stores charge for that service)


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## wcoastwhacker (Aug 7, 2011)

i looked at homedepot.com for CDX plywood and it says its pressure treated which according to this site is a horrible choice for aluminum. any other suggestions or input?


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## MoHops (Aug 7, 2011)

Ok. I looked at Home Depot's website and they have it listed as 23/32 RTD plywood. That's what you want. Store SKU #166103

Looks like they also have a product called DryPly. It has a water repellant treatment already applied. It does have a tongue and groove edge though and costs a little more.


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## wcoastwhacker (Aug 7, 2011)

i found the 23/32 plywood thanks for the input! BUT isnt pressure treated bad for aluminum boats? (it erodes the aluminum or something?)


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## MoHops (Aug 7, 2011)

That RTD isn't treated. It's just plain old pine plywood. RTD has to do with the glue up process of the veneers. It has an exposure 1 rating which is the same as CDX. Clear as mud right?

And yes for the most part treated will corrode your boat. The newer stuff (MCA) is supposed to be safe for metal contact. However, they don't recommend it on metal in areas that will always be wet (like a boat)


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## wcoastwhacker (Aug 7, 2011)

ok your right. i looked up the sku # and found the wood you were talking about. Thanks!


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## MNHunter505 (Jul 22, 2012)

Hey all, newbie here and have been using the search function to answer most of my questions. So, before I buy, just wanted to re-confirm the following process for decking in my 16ft boat: 3/4" exterior plywood and coated with spar urethane? Also, after coating it with spar urethane, will I be able to use adhesive and carpet on it?


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## Backslider (Jul 22, 2012)

I used 3/4 in exterior grade plywood and coated it with epoxy. I covered it with outdoor carpet and riveted the deck to the rails that support the deck.


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## MNHunter505 (Jul 22, 2012)

Backslider said:


> I used 3/4 in exterior grade plywood and coated it with epoxy. I covered it with outdoor carpet and riveted the deck to the rails that support the deck.



Backslider, thanks for the input. I found the same wood at Lowes for like $31. So that will work good for me, price too. 
Next question is what to seal it with. Will thompson water sealer work? I saw some posts of Spar Urethane, it's approx. $17 for a quart. You say epoxy, can you be more specific? Also, how much did you need and the price. Thanks.


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## Backslider (Jul 22, 2012)

I used West System 105 resin and West System 205 hardener. I bought the pumps that screw onto the cans and they deliver metered amounts in the right proportion. It takes all the guess work out of the ratio of hardener to resin. One pump of resin and one pump of hardener and you have the right mix. I also used their epoxy rollers on a regular paint roller handle. I'd never used epoxy before. This stuff was easy to use. Just pour a puddle and roll it out. I think the pot life is around an hour.

I have a 17' boat with a elevated front deck. I used 4 sheets of plywood, coated the top and bottom of each piece (after it was cut to size :wink: ) put two coats on the top side, also replaced the transom and epoxied the heck out of it too. I used a little more than one can of resin and hardener (Resin 32 oz, hardener 7 oz). The stuff keeps, so I'll use the rest on my next project. I bought it oneline from Jamestown Distributers.


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## Backslider (Jul 23, 2012)

Oops. I went out and shook the cans. I used almost 2 cans of epoxy and almost 2 cans of hardener.


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## krawler (Jul 23, 2012)

Two tips that I can add; 1, buy the thinnest and longest dry time epoxy you can find. 2, When applying the epoxy use a plastic squeegee/spreader instead of a paint brush. Mix it up, poor it on, then spread it around to coat the surface. Let it soak for a few minutes to "wet" the wood, then squeegee off the excess. You only need a wet coat to seal the wood, adding a heavy coat just adds weight and waste product. A paint brush might work better on the edges, just make sure to squeegee off the excess.

My .02 worth!


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## MNHunter505 (Jul 23, 2012)

Sounds good. I am def going to look into the epoxy and different tips ya'll provided. I have a 16th flat bottom so I will prolly buy two cans of each as well.


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## MNHunter505 (Jul 24, 2012)

Backslider said:


> I used 3/4 in exterior grade plywood and coated it with epoxy. I covered it with outdoor carpet and riveted the deck to the rails that support the deck.



Check out my pics...do you think I could get away with 1/2" plywood? Or are the ribs to far apart.. Trying to cut down on some weight. I plan to just lay the plywood across the ribs with insulation in between.


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## MNHunter505 (Jul 31, 2012)

morning bump..


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## wihil (Jul 31, 2012)

If you get some backing foam in there between the ribs, I'd think 0.5" would be fine. The biggest thing is to be able to support the areas that don't have the ribs.

There was a build on here where someone had a similar style boat that used the blue foam to fill the gaps, and then covered the bottom with a rubberized roofing sheet (which was a pretty cool idea IMO), and it was stiff enough with no problems - and removable. 

Either way, make sure you leave a channel down the middle for the boat to drain correctly!


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## Scorched (Aug 8, 2012)

I am in the middle of a 1986 16 ft bass tracker rebuild, it had 1/2" exterior grade plywood with foam in between the ribs from the factory. I'd say you'll be fine with 1/2"
It lasted 26 years. The middle sections of the floor were still solid but the outer few inches were rotted out.


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## MNHunter505 (Aug 8, 2012)

Scorched said:


> I am in the middle of a 1986 16 ft bass tracker rebuild, it had 1/2" exterior grade plywood with foam in between the ribs from the factory. I'd say you'll be fine with 1/2"
> It lasted 26 years. The middle sections of the floor were still solid but the outer few inches were rotted out.



ok, thanks. With your input and a lot of others, I am going with foam in the middle and 1/2" plywood. 

Are you using spar urethane to coat your plywood?


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## Backslider (Aug 8, 2012)

I used the 3/4 inch plywood because I have a couple buddies who weight 275 lbs + and I want to put in pedestal seats. I was looking for a bit more strength in the deck. Also, I put blue foam insulation under the deck for flotation, too. That took out the flex in the plywood near the side edges of the sheets.

Another note, I put my carpet down using Liquid Nails and just I've learned, and as another Tin Boats member said, its water soluble and will come loose in the rain. It is and it did. #-o Luckily the rivets are holding it in place well enough to get by this summer.


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## MNHunter505 (Aug 8, 2012)

Backslider said:


> I used the 3/4 inch plywood because I have a couple buddies who weight 275 lbs + and I want to put in pedestal seats. I was looking for a bit more strength in the deck. Also, I put blue foam insulation under the deck for flotation, too. That took out the flex in the plywood near the side edges of the sheets.
> 
> Another note, I put my carpet down using Liquid Nails and just I've learned, and as another Tin Boats member said, its water soluble and will come loose in the rain. It is and it did. #-o Luckily the rivets are holding it in place well enough to get by this summer.



Yea, ended up reading about the carpet glue debate too. So I went and bought some waterproof adhesive from a local carpet shop, called Anchor 986. It's the same difference as Henry's 263 which has been tested waterproof.

As for the plywood, after reading your post, I just don't know, I keep going back and forth. I am only 160 but by buddy is 285. I am thinking that 1/2" would be fine with foam inserts but I am trying to do the same thing you did and put pedestal seats in. So I am guessing I would need that 3/4" plywood to secure the pedestal plates down?


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## Scorched (Aug 10, 2012)

I will probably use polyester resin (fiberglass resin). I have used it in the past for out door projects and it has worked well. Its easy to apply/work with - Set time is very short as well.

Then again, the original tracker wood had no treatment that I can tell and iit was probably good for 10-15 years before it started to break down...doubt if any of us will have the same boat in 10 years, you never know though. Do it once, do it right, right?


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## MNHunter505 (Aug 10, 2012)

Scorched said:


> I will probably use polyester resin (fiberglass resin). I have used it in the past for out door projects and it has worked well. Its easy to apply/work with - Set time is very short as well.
> 
> Then again, the original tracker wood had no treatment that I can tell and iit was probably good for 10-15 years before it started to break down...doubt if any of us will have the same boat in 10 years, you never know though. Do it once, do it right, right?



True, doing it right the first time always is best. You just have to balance that with cost. I plan to use spar urethane but will look at cost to determine that or polyester resin.


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## Scorched (Aug 10, 2012)

I like the polyester resin because if worked with fiberglass for years.

There's more than one way to get it done.


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