I just bought a sheet of 1/2" Douglas Fir MDO Plywood at Lowes. Actual thickness: 0.484. The entire stack (50 sheets?) was flat as can be, no gaps between sheets. $73.98
My other choice was 1/2" Southern Yellow Pine Plywood Sheathing Actual thickness: 0.438. All through out the stack (50 sheets?) you could see gaps where many sheets were so warped, they pushed all the sheets above them up. Gaps > 1". $75.25
This was my first purchase of MDO. I just assumed that it would be more expensive than crappy sheathing. I don't need MDO for my project, but why not? Cheaper, thicker, flatter - and I don't have to pick any 2 of the 3. ;-)
We didn't have any problems with it; maybe it depends on the grade, or the nails, or the technique. Of course, we were only nailing *through* the osb, not *to* it.
The laminate is generally water resistant (or even water proof) but if you get water under it, you're at the mercy of whatever's under there. If the underlayment is fiberboard it will swell like a sponge. If the underlayment is wood, it won't.
Right. I was thinking about nailing shingles *to* it. One of my previous houses had OSB sheathing. When I replace the (cedar) siding, I had to nail into the studs to get them to hold.
I suppose it depends on paint to keep the edges sealed. At $71/sheet it should be gold!
I've looked but I can't fine any reference to fiberboard being used as an underlayment. Everything I've read so far indicates that the core is all wood. So references even discuss the sanding of the top and bottom plies to ensure good adhesion with the overlay.
Some also talk about
Curtis says it's 100% waterproof
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"How Is MDO Plywood Made? Using layers of C grade and B grade wood, the thin wood veneers are layered perpendicular to each other to provide stability. In between each veneer a layer of waterproof resin is applied, and then everything is fused together with heat and pressure. The overlay coatings are made from waterproof resin-impregnated fiber, making MDO 100% waterproof."
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"The Resin Most wood panel products are manufactured using either a urea formaldehyde or a phenol formaldehyde adhesive. The difference between the two and why one would be used over another has a lot to do with urea formaldehyde being a water resistant adhesive and phenol formaldehyde being waterproof. Manufacturing cost and emissions are also factors. (APA, 2015) MDO plywood uses a phenol formaldehyde resin, also known as a phenolic resin, to adhere and saturate the overlay as well as bond the plywood veneer together. "
I can certainly see an issue if the edges aren't sealed.
So no, it is not always cheaper but times are strange right now. Not many people know about it and demand "has" been low.
I pay $69 per sheet for 3/4". Until last week, the price went up to $89 per sheet. AND they had to check to see if they had any left.
I got it for my regular price but I think they are doing what all suppliers are doing now, marking up low inventories.
This is the stuff that highway departments used to make road signs out of. It Paints up great.
Also the inner plies tend to be higher quality, reminiscent of how plywood looked 50 years ago and thickness is verrrrrry close to what you expect it to be.
The surface smells like plastic laminate does when milled. So basically the surface is a craft like paper with infused with a resin.
Little to no splintering when cut.
Currently I am working on a Murphy bed set.
The bed is done except for a permanent pull handle and I am currently working on tower cabinets on both sides of the bed. The panels in all of the pictures below are MDO.
The one thing that I found (and totally expected) is that the laminate is so thin that putting a roundover on the sheet did not come out very pretty. But, in my case I knew it would happen and really don't care.
I will be covering the material with carpet and wanted to soften the edge so the carpet wraps around easier. I'm making two platforms for the back of my Odyssey. One will be for the rear cargo area when the 3rd row bench is stowed in the floor. That platforms will stay in the Ody >99% of the time. The second platform will be used when the 2nd row captain chairs are removed. The platforms are built, carpeting to start tonight.
With each generation of the Ody (approximately every 5 years) they made the floor less and less smooth. My 04 was almost complete flat. The 06 was a little worse and my 17 is a real PITA. The 18+ vans are even worse.
It's hard to tell from this picture, but that hump is about 3" high. It may look like it just slants downward, but it's actually a hump. (3rd row bench hinges).
The goal is to go from this:
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To this, with the 2nd row seats in....
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...and this with the 2nd row seats out.
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One full sheet of MDO, a 8" x 33" patch of 1/2" sheathing (scrap) and a couple of 2 x 4's to level it all out.
That would be the case with any plywood. Wood veneers on plywoods are getting pretty thin! Way too freaking easy to sand through the veneer. So adding an edge, to hardwood veneer plywood, has to be attached perfectly or proud of the veneer surface.
FWIW I switched to MDO years ago when I am going to use paint for the finish. I simply cannot depend on the outer veneers, on paint grade plywood's, to not de-laminate, even with oil based products. I ran into that about 7 years ago and was not happy. AND another reason that I prefinish panels before assembly. At least then I have a chance to correct the problem with a replacement piece. Finishing, especially painting after assembly is both risky and much more difficult.
The bed probably took me less than 45 minutes to paint and clean up. The 6 panels for the lower tower cabinets. Probably 20 minutes total and 10 to clean up. I used a small foam roller for 98% of the painting.
I used General Finishes Milk Paint. Super easy to use.
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