View Full Version : Deck plywood thickness

08-08-2012, 04:07 PM
What is the size plywood that Gibson used on a 1982 houseboat deck from the factory? Need to repair a section of deck.

08-08-2012, 05:36 PM
So far all of the marine plywood I've seen on our Gibson is 3/4"

08-08-2012, 07:13 PM
I'm assuming you have soft spots anyway, so I suggest you drill a hole and take a measurement.......they may have done things differently in 82 then 83. I would not be surprised if you find it to be a bit under 3/4", but not a standard thickness. If this is the case you will just need to purchase the next size below what you have and pad your joists a bit. Just FYI, it's not necessary to to use marine plywood for the repair as they didn't use it originally. Just non treated exterior glue plywood will do the job just fine.

08-09-2012, 01:13 PM
Yes I will be repairing a section this fall. Will be using exterior ply and epoxy. Was searching for information and can't find anything about the material thickness on the deck.

Frantically Relaxing
08-09-2012, 09:54 PM
I repaired a chunk of my roof this summer, and you're likely going to run into the same problem I did: Plywood these days is thinner than in the 'old days'. So, if you had 5/8" plywood before (which you probably do), todays 5/8 is 19/32, and 3/4 is 23/32. So 3/4" is still too thick, and 5/8" isn't thick enough. I ended up shimming my patch to bring it level. And I also found out, plywood swells up over the years. I could've ALMOST gotten away with using 3/4", but not quite...

08-10-2012, 06:35 PM
Well think I will just go with 3/4. Will probably just redo the entire deck over the next year or so anyway.

08-12-2012, 06:51 PM
That's because most plywood today is manufactured to metric sizes. It may be advertised as 1/2" but it's actually 12 mm, or 3/4" but it's actually 18 mm ( 3/4'= 19.05 mm, 18 mm = 23/32 12MM = 15/32 13MM = 1/2")

Plywood today comes mostly in the following sizes 4mm, 6mm, 8mm, 12mm, 18mm and larger.

Good wiki page on plywood http://en.wikipedia.org/wiki/Plywood

Best source of info on plywood, The Engineered Wood Products Association (Used to be called the American Plywood Association - APA) http://www.apawood.org/

08-15-2012, 08:03 PM
Thanks I will let you know how I make out, should be in a couple weeks when the weather cools down