has anyone used 3/4" CCA Treated Plywood for decking on a jon boat?

I used 1/2" on my john boat with 2x4s ripped in 1/2 glued and screwed it was fine for years. I got it at the lumber yard. You should find it at HD or Lowes

 

Same here. Lasted about 5 years with a light resin coating and carpet.

 

I used untreared yellow pine 2x and regular plywood. If you coat it and seal the ends good you should get several years out of it.

 

Take a look at some MDO - it is used to make outdoor signs - has a much nicer finish.

 

Just be sure to use a outdoor carpet with rubber under and the plywood will work for a longgg time. (home depot)

 

i have 1/2 inch treated ply ( the regular old green pressure treated pine stuff) for the floor in my tunnel boat.. its been in there baking in the sun and getting wet when fishing, or rain for about 6 or maybe 7 years now...its just now starting to get kinda brittle on the edges...ill get another season out of it though..

if you can, i suggest letting it get good and dry before putting it in your boat...when wet from the store its heavy....

i havent been to the lumber store in a while but i dont think they sell the green pressure treated ply anymore...i think its some other kinda treating they do nowdays...not sure how it holds up...

 

fwiw...not to discourage or anything....just for information purposes..

i built a little puddle boat out of 3/8 exterior ac ply... glassed over it with just polyester resin and mat glass from lowes...primed with latex kilz and painted with exterior paint.. its about 2 years old now i guess...its been 100% out in the weather with no protection whatsoever...some of the corners that had the glass/resin chipped off from dragging it around are pretty rotted...the rest is for the most part still structurally sound...i would still get in it right now...it doesnt leak or anything..

my point being...if you protect some regular ext ac with something itll last for a couple years..

 

I would not use Pressure Treated Plywood on an aluminum boat. Today, 98% of "treated" plywood is made with ACQ (Alkaline, Copper, Quat) and is highly corrosive to anything Aluminum. You nice Aluminum skiff will corrode!

In addition, resin will not bond to pressure treated lumber nearly as well as untreated lumber.. Treated lumber is not a good choice for boats.

I have 22 years in the wholesale lumber trade, so I know a little bit about pressure treated lumber.

 

You do not need anything heavier than 1/4 in plywood for a deck. If it makes you feel better glass a couple of stringers to the underside of the deck running fore and aft. Keep it light if you can. All Gheenoes and made with 1/4 inch decks.