# Replacing carpeted floor- to use marine ply or not?



## dexterm16 (Feb 26, 2008)

getting ready to replace the floor in my 20ft alumacraft . Plan to reinstall like factory with either new or re-using existing carpet depending on shape. I understand my options for plywood but not sure of the answer - use marine ply or not? I plan to match the floor thickness which I believe is 3/4 but do I use exterior grade ply from Lowes or splurge on the marine ply. I have a local dealer that stocks 3/4” marine ply at about 80$ a sheet and I’m look at about 2 sheets right now and maybe a 3rd in the future. Incase it helps boat is a 1990 and I play to run it for a few more years if possible. Plan to upgrade it for my needs ( electronics and layout) and buy a newer boat when my Son gets a bit older .


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## bountyhunter (Apr 28, 2004)

how about a aluminum flr?


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## dexterm16 (Feb 26, 2008)

bountyhunter said:


> how about a aluminum flr?


To hard to fabricate to allow for seat mounts and texture for traction


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## Harry1959 (Mar 17, 2011)

I’ve read over and over to not use standard pressure treated plywood on any aluminum. The chemical in the PT plywood will interact with and corrode the aluminum. Also, a lot of the marine plywood isn’t actually treated. Some is treated and is safe for aluminum. I would probably buy marine plywood. If it’s not treated, put clear penetrating epoxy on it. It’s good stuff and actually penetrates inside the plywood and hardens. Pretty sure the makers of CPES say it’s fine to just use exterior plywood as long as it’s coated with cpes. Google Smiths cpes and rot dr CPES. Both their sites have a lot of information.
When I rebuilt my pontoon boat I used pretreated marine plywood and also put Rot dr. Cpes in it.


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## MikeC (Jun 26, 2005)

No opinion on the wood, but if you're fishing in it mostly, I'd go with a vinyl floor. I keep the carpet shampoo/cleaner industry in business gettin' the mud, blood and beer outta mine, lol.


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## Harry1959 (Mar 17, 2011)

Don’t know if you have carpet yet. I bought mine on line at “boat carpet buys” some of what they sell is equal to or better than OEM carpet, and cost is comparable to the cheaper carpet at the box stores. They will also mail you free samples to choose from. boat carpet buys is affiliated with “pontoon stuff” I bought my treated marine plywood from them, but wasn’t happy with it as it had voids on the smooth side, which is not Generally characteristic of marine grade plywood. They ended up refunding my money and letting me keep the wood, so I bought the appropriate filler, repaired the voids myself and used it. I required 8 1/2 x 4 and it was really difficult to find.
As Mike said most like the vinyl flooring Much better. Hose it off when dirty, will last longer. Carpet will hide voids better and is pleasurable to walk on, especially barefoot. And good carpet will also last a long time if taken care of.


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## My Demeyes (Aug 2, 2010)

Don't go cheap with PT plywood, it will destroy your boat in only a couple years. It won't be worth much, when you're ready to upgrade boats. I've used the marine plywood from menards on a few different boats, for transoms and floors, epoxy coated both sides. Will last longer than factory installed plywood. 

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## Specwar (Sep 22, 2014)

My alumacraft has aluminum flooring which I thought was their standard. Have you removed your old carpet yet to be sure yours has plywood?


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## mmtchell (Jul 9, 2014)

Did my alumacraft trophy 190 and it was 1/2 inch ...and only use marine plywood. ..just make sure the foam underneath is not saturated with water if so get it out and replace ,,,thats what supports the floor ,,,


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## ducknut141 (Apr 26, 2017)

My floor was only 1/2 inch also. I cut and fitted everything and put two coats of marine epoxy on it on both sides before I installed it. After installing it with large head rivets and screws which got sealed as they were put it I put another coat of epoxy over the wood before installing the carpet.


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## s.a.m (Feb 22, 2016)

Exterior and pressure treated are two different things, no pressure treated on aluminum, but exterior has the same glue as marine the marine just has less voids


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## spectrum (Feb 12, 2013)

^^^^ what s.a.m said... I just used exterior on my boat. I was lucky and the lowes by me had sheets that were more or less perfect. Figure by the time the floor rots the carpet will be shot anyway. The hardest part of all of it was ripping out the floor, which for me came out in hand size peices. (bought boat used) Then making the blueprint of the floor. I saved the blueprint so if I ever need to do it again it'll be cake. Also used SS screws instead of rivets and such...couple zip, zips and the floor will come right out.


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## M.Magis (Apr 5, 2004)

s.a.m. is correct, marine and exterior are the same thing, other than the voids in the wood. You don't need marine grade for flooring.


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## Popspastime (Apr 1, 2014)

Your going to go thru all this work and investment and use cheap exterior grade ply? I don't get it.


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## My Demeyes (Aug 2, 2010)

Popspastime said:


> Your going to go thru all this work and investment and use cheap exterior grade ply? I don't get it.


Some guys just insist on learning the hard way. 

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## fastwater (Apr 1, 2014)

If I were going through the effort of replacing mine, it would be done with Marine grade. And wood would be sealed as well. Same if going with wood on the transom. Less 'voids' ='s stronger,more durable and less 'voids' for less chances for moisture to seep in over time. Marine grade is just gonna last longer.


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## Popspastime (Apr 1, 2014)

fastwater said:


> If I were going through the effort of replacing mine, it would be done with Marine grade. And wood would be sealed as well. Same if going with wood on the transom. Less 'voids' ='s stronger,more durable and less 'voids' for less chances for moisture to seep in over time. Marine grade is just gonna last longer.


It's called TPS.. Tucked, Plugged, and Sanded. Exterior only has a different glue and is NOT structural with a open voids thru out and 4 to 5 ply at best, maybe 4 in 1/2 inch. Marine grade uses exterior glue, no voids, and 7 to 9 ply's when produced. You still have to seal it for longevity. Marine grade or Composite is the only way to do it right.


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## M.Magis (Apr 5, 2004)

LOL Some of you don't read closely or just like to argue. If it's for a transom or cabinet work, it needs to be marine grade. For flooring that'll have marine carpet glued to it, exterior is all that's needed. Using marine plywood under carpet is like putting custom hardwood flooring under carpet in your house. You're spending more money for the exact same end product.


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## Popspastime (Apr 1, 2014)

Not even close..

Marine plywood is constructed out of the finest grade of naturally water-resistant tropical hardwood. To ensure the best results, only the highest quality grade of veneers are used. That’s because high-quality veneer is free of defects, which means that when the sheet is cut, core gaps are practically done away with.

To put things in perspective, let’s take structural plywood for example. Structural is already a great plywood product, but the high grade veneers used in every layer of marine plywood makes the latter an even better kind of plywood. And if we are talking about higher-quality marine-grade plywood, you know it is so much stronger and more durable because it’s made up of more and thinner layers of hardwood.

What makes marine plywood perfect for wet and moist external applications is the fact that it is bonded or glued together using phenolic resin. This type of glue, in combination with the already water-resistant hardwood, makes it completely waterproof. Made to AS/NZS 2272 specs, So you do what ever you want but don't tell me their the same.


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## fastwater (Apr 1, 2014)

^^^Well said Pops^^^
If there were no difference in marine grade versus exterior grade plywood, they wouldn't 'grade' them differently.
To each their own and I don't really care if someone else uses cardboard in their boat.
Bottom line is if I use wood in my boat for whatever reason...it will be sealed,marine grade period!


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## My Demeyes (Aug 2, 2010)

Doesn't take much research









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## spectrum (Feb 12, 2013)

Just a thought... but if your gonna seal the wood anyway, what's the point. Water shouldn't get in the wood anyway. Talking about just exterior not PT.
I didn't seal mine...figured I would just see how it goes. Now if I was doing a transom, or owned a 30K rig, then I'd do a overkill on it.
I get it though...best material and stuff is the way to go if you never want to touch it again. I bought my boat for 5k, it's a little beat up but I always say "it's a fishing boat, that's how it should be"  Plus I like the fact that I don't have to be nice to it, which some of my friends always comment on. "Nice to be on a boat when you don't have to worry about spilling your coffee, getting fish blood on the carpet, or wacking the dock too hard and messing up the gel coat...oh wait, I don't have a gel coat, just another character scratch. 
But to each his own...guess the OP got his ? answered.
Couple pics for your amusement.  2015




























View attachment 290783


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## s.a.m (Feb 22, 2016)

Popspastime said:


> Not even close..
> 
> Marine plywood is constructed out of the finest grade of naturally water-resistant tropical hardwood. To ensure the best results, only the highest quality grade of veneers are used. That’s because high-quality veneer is free of defects, which means that when the sheet is cut, core gaps are practically done away with.
> 
> ...


you speak of bs1088 marine grade, also exterior plywood uses exterior glue/resin, that's why they call it exterior grade!


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## fastwater (Apr 1, 2014)

Just curious...for those that have done it and suggest using exterior plywood for this job, what grade of exterior plywood do you recommend?
And since the exterior plywood is assembled with exterior glue did you totally seal it with epoxy as well...or is that not needed because of the exterior glue?


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## s.a.m (Feb 22, 2016)

fastwater said:


> Just curious...for those that have done it and suggest using exterior plywood for this job, what grade of exterior plywood do you recommend?
> And since the exterior plywood is assembled with exterior glue did you totally seal it with epoxy as well...or is that not needed because of the exterior glue?


I put a bench seat over my fuel cell used exterior plywood and painted with porch and floor oil base paint, looks like the day I did it three years ago. In the weather from spring till winter


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## fastwater (Apr 1, 2014)

s.a.m said:


> I put a bench seat over my fuel cell used exterior plywood and painted with porch and floor oil base paint, looks like the day I did it three years ago. In the weather from spring till winter


What grade exterior plywood is it?


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## Harry1959 (Mar 17, 2011)

I said my opinion earlier.....would use marine grade, you can’t expose aluminum to the non marine grade treated plywood, and want to add, There is no way I would use regular exterior plywood without sealing it with epoxy. 
Also Mmitchel said the wet foam should be removed because it supports the floor? I agree to remove the flotation foam if waterlogged, I’ve used spray insulation foam to replace...... However, I don’t know if this is the best option?
I’ve gutted 3 fiberglass runabouts and all their floors were supported by wooden stringers between the outer hull and floor. I would think any boat floor would have either aluminum or wood stringers to support the floor. The floatation foam is between the stringers and floor.


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## s.a.m (Feb 22, 2016)

fastwater said:


> What grade exterior plywood is it?


Of the shelf Lowe's 5 ply 1/2 don't remember the grade


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## fastwater (Apr 1, 2014)

Good call on the insulation Harry.
Long as it's 'closed cell' insulation, it should hold up fine.
Another thing worth mentioning to replace when the floor is up is any rubber fuel or water lines that may be under the floor. And definitely check all wiring as well. Taping the wiring harnes and running the harness through PVC tubing isn't a bad idea either.


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## fastwater (Apr 1, 2014)

s.a.m said:


> Of the shelf Lowe's 5 ply 1/2 don't remember the grade


Okay Thanks s.a.m.!

Anyone else that used exterior plywood for their boat floor care to share what grade they used?


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## spectrum (Feb 12, 2013)

The stuff I used was either 1/2 or 3/4 don't remember, grade PS1-09/ veneer grade BCX (lowes). I may be right or wrong but I didn't seal it. My thought process at the time was this boat only sees water for maybe max 10% of the year and 90% of that time the wood only gets a little water on it from a fish. The rest of the time it's sitting on a trailer all nice and dry under a cover. If I don't seal it right or a crack develops water might get in the wood then it won't be able to dry causing it to rot.


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## slimdaddy45 (Aug 27, 2007)

I would use bcx plywood never use treated in an aluminum boat . I would either use epoxy or incase it in a layer of fiberglass to seal it up .No need for marine grade for a floor transom yes .I did a transom and used marine because of the layers and no voids which is stronger but a floor regular ply is ok but I would seal it so probably never have to be replaced again. I need to pull my floor up to replace my livewell drain hose its busted someplace just drains in the boat and when I do I want to use 3/4 ply and im going to fiberglass it since I already have the material to do it .It has 1/2'' in it now I think it gives some on me since Im a big guy my carpet is good so maybe I can reuse it don't know if not I may use seadeck or whatever its called where you paint it don't need carpet in a fishing boat since I mostly fish for big slimey catfish


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## privateer (Apr 26, 2012)

you could put a couple coats of west system expoxy on the wood. that will seal it and it is so tough that you could even skip carpet or vinyl on top. if you want non-slip, you could do what i did in the motorcross trailer... after coating the floor, and while still wet, I sprinkled that flooring sand all over the thing. it is so rough now that you can't even sweep the dirt out, have to use the compressor and blow it out. made a sprinkler out of a peanut butter jar with holes drilled in lid. coating mfg suggests mixing in paint and the put on surface, I thought a "salting" of the sticky surface would work better and i have not been disappointed since did that back in about 2000. still rough as ever too...


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## fastwater (Apr 1, 2014)

spectrum said:


> The stuff I used was either 1/2 or 3/4 don't remember, grade PS1-09/ veneer grade BCX (lowes). I may be right or wrong but I didn't seal it. My thought process at the time was this boat only sees water for maybe max 10% of the year and 90% of that time the wood only gets a little water on it from a fish. The rest of the time it's sitting on a trailer all nice and dry under a cover. If I don't seal it right or a crack develops water might get in the wood then it won't be able to dry causing it to rot.


Thanks spectrum!


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## slimdaddy45 (Aug 27, 2007)

spectrum said:


> Just a thought... but if your gonna seal the wood anyway, what's the point. Water shouldn't get in the wood anyway. Talking about just exterior not PT.
> I didn't seal mine...figured I would just see how it goes. Now if I was doing a transom, or owned a 30K rig, then I'd do a overkill on it.
> I get it though...best material and stuff is the way to go if you never want to touch it again. I bought my boat for 5k, it's a little beat up but I always say "it's a fishing boat, that's how it should be"  Plus I like the fact that I don't have to be nice to it, which some of my friends always comment on. "Nice to be on a boat when you don't have to worry about spilling your coffee, getting fish blood on the carpet, or wacking the dock too hard and messing up the gel coat...oh wait, I don't have a gel coat, just another character scratch.
> But to each his own...guess the OP got his ? answered.
> ...


Is that a Sea Nymph boat kinda looks like mine and I need to remove my floor for my livewell drain


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## spectrum (Feb 12, 2013)

Na, 1990 spectrum by blue finn. 19'




  








boat




__
spectrum


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Jul 24, 2013


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## tm1669 (Apr 27, 2007)

Marine grade is wasting money if your sealing it with epoxy resin. You can be use any grade exterior ply (except pressure treated) and it will be fine.
If not using epoxy a few coats of oil based paint or several coats of spar urethane will seal it up real well but you will want plywood with as few voids and as many layers as possible.
Arauco is a real good ACX ply if you can find it. Menards carries it but not HD or Lowes. Its less than half as much as marine ply and the quality is supposed to be comparable.
Go over to iBoats and search their boat restoration forum. There are pages of info about boat plywood and different materials/methods of sealing them. I will warn you ahead of time that there are so many awesome restoration projects documented on iBoats that it might have you tearing your whole boat apart. 
Also for floatation foam Im using cut 2" closed cell insulation board. My Starcraft has waterways at the middle of the ribs that need to stay open so water that comes on board can get back to the bilge. Those have to stay open. Much less messy than the spray in foam as well.


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## jonzun (Jun 11, 2004)

How about 1/2in thick Veranda 48in x 96in PVC Panel at Home Depot $64.98 a sheet. Here is the link: https://www.homedepot.com/p/Veranda...llular-White-PVC-Panel-HDSHSM124808/301950563


Hard surface protects against dents and weather damage
Fire-retardant vinyl material protects against rot and termites
Durable vinyl material for exterior or interior use


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## I Fish (Sep 24, 2008)

If you use a 2 part expanding foam, be mindful of the temperature requirements, or else it won't expand to it's potential.


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## Morrowtucky Mike (May 2, 2018)

I keep reading everyone saying to paint or seal the plywood. Yet the exterior grade carpet glue I bought and all the others I looked at said to not use on finished surfaces. So is it ok to go against the manufacturers recommendations and use it on sealed plywood anyways?


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