Do I need marine ply for my project?

Do I need marine ply for my project?

So I got an email from a fella named Grant the other week, who had picked up on my mention of marine ply in the article DIY False Floor. An Alternative To Drawers. 

I, like just about anyone else who’s been reading forums and other esteemed publications for the last few years or more; had come to believe that marine grade plywood is entirely waterproof and therefor the best option for longevity. Apparently this is not the case.

My cheap plywood false floor is still holding together!

My cheap plywood false floor is still holding together!


The most common argument I hear in favour of marine ply is the use of an expensive waterproof glue which will prevent the layers separating. That’s a fair assumption, how else could it be any better when it looks the same? Grant assures me that the only difference is that marine ply uses a “clear veneer” which is basically a better finished veneer with no knots. The idea being that if you are shaping a boat hull, you don’t want to be cutting or sanding a knot which may pop out later down the track (and probably sink your boat I guess!).

Okay, so who the heck is Grant to be telling us all this? Grant is the Timber Supply Manager at Hayters Timber & Paving Centre in Narellan, NSW. Grant has tested different grades of ply as backing boards for paving displays outside the shop. These sit outside the store 24/7 365 days a year and the marine ply has lasted no longer than the standard ply. Paint the edges to minimise water and moisture ingress and they both last just as long.

So there you go…Don’t go wasting your money on marine ply! And if you do, go see Grant at Hayters Timber & Paving centre so as he can talk you out of it. If you still want marine ply though, I’m sure he’ll gladly take your extra money to put towards his next adventure haha!

For further reading, here’s a few links that Grant turned up on the web. Thanks for all your efforts mate! – – –



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  1. Harry Fisher
    May 06, 09:12 Reply
    Well that is bloody brilliant. I was going to avoid some free ply in favour of going and spending money on the marine stuff. Cheers for the heads up Grant and Alex!
  2. JW
    May 06, 15:11 Reply
    Most of this is incorrect proper marine ply has thinner but more veneers increasing the strength and impact resistance which is why it is used in marine applications ie hulls
    • Alex Garner
      May 09, 12:04 Reply
      Cheers for the input mate :) Good to be informed of another difference between the two!
  3. Grant
    September 19, 19:32 Reply
    JW, you are a little mistaken but thanks for your comments. It is purely the grading of the timber they use in the veneers, not it's thickness so strength doesn't come into it. And ultimately, in the rear of a warm cozy 4x4, how much of a beating are they going to cop anyway. But again, thanks for your comments. Bit like how people cover their boxes ( or even the expensive Chinese made ones all the 4x4 super centres flog off ) with marine grade carpet. Last time I looked most 4x4's had roof's on them so not too sure how much water people expect to get in their 4x4's but maybe if water ingress is that much of a worry, then they're using their 4x4's in the wrong way lol. Cheers
  4. BW
    March 12, 08:25 Reply
    Well there you go. Thanks for spending the time to show us the difference.

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