I've had nothing but problems with plywood

[Dan & Julie CO]

Speckles, my last dog, is buried in the back yard in a box made from left-over plywood from my bathroom remodel. The plywood is an orangish-color, tongue-in-grove, 3/4" thick, "moisture resistant" plywood from Lowe's. The ground is still level where she's buried....so I guess the plywood is still intact after two years. I'd say that's pretty good advertising for "moisture resistant".

I think being buried in the dirt helps, it creates an absence of air, which slows down the deterioration process .

[mikeschn]

We did some more disassembly this weekend. It's amazing the amount of rot we found, due to the cheap luan we used on the roof.

After thinking about it for a few weeks, and looking at the rotted plywood, I concluded that the new supplier that we switched to in the middle of our build did not furnish us with moisture resistant luan.

So after a couple years of water pouring in, some of the plywood was pretty bad...

For example...



BTW, this is all that is left of the Giant Teardrop build...



Mike...

[Dan & Julie CO]

Man that's gotta hurt

[Wolfgang92025]

Mike,

Major bummer......
All that blood sweat and money....
Looks like the only good thing is you are able to salvage the frame.
Guess that makes the foamie design so much more attractive for you.

[kirkman]

Ouch!

[2bits]

Sorry to see that Mike... I thought with Luan, there were more voids. Is miosture resistant Luan different? The name sounds suspect, like it resists moisture getting in, but may not address moisture accumulating in the voids. I may be totally off-case, as your teardown will tell volumes on this for where the origination point of the rot began, inside out, outside in, end grain, etc...

[mikeschn]

I'm reminded again about how my house was built in 1920. The outside is covered in cedar siding. The siding looks as good as the day it was put up. The paint not so much so... But after 92 years, for the cedar siding to still be good, no sign of mold, rot etc... A good sanding, and a fresh coat of paint and the house looks brand new again.

So I'm back to thinking about cedar for my next build...

Mike...

[Larry C]

I'm reminded again about how my house was built in 1920. The outside is covered in cedar siding. The siding looks as good as the day it was put up. The paint not so much so... But after 92 years, for the cedar siding to still be good, no sign of mold, rot etc... A good sanding, and a fresh coat of paint and the house looks brand new again.

So I'm back to thinking about cedar for my next build...

Mike...

Mike... Very good thinking especially for those of us living in the "Rot Belt"

[Jiminsav]

the thing about Ceder is it splits real easy along the growth rings..as long as it's stationary, it's fine, but movement on the highway may be a bad thing..maybe pine covered by cedar?
or, that just may be the cedar that grows around here.

[Lgboro]

I'll know after the summer if cedar will hold up. Have a 15,000 mile trip planned from coastal NC to AK and home by way of San Diego. I haven't finished my tear yet but I have only used cedar frame work and cedar strip interior including a 1/2 inch cedar floor. All frame work was biscuit joined and dowel pinned. Walls and ceiling sandwiched with 2 layers of blue foam insulation and sub 1/8" cedar strips glued with Gorilla Glue. Cabinets were built in as part of the structural strength of the torsion box. (I know many here claim this glue won't hold either) I also built on a Tractor Supply trailer that has inspired its share of negative posts. Pains have been taken to build as strong and light as possible so I guess time will tell. I have full confidence that my tear is up to any trip without structural problems.

Honestly, if I were starting over I would use 1/2 " instead of 3/4" for my framing as I made a T shaped beams with opposing grains. Overbuilt - probably but as lightly as possible.

[48Rob]

But after 92 years, for the cedar siding to still be good, no sign of mold, rot etc... A good sanding, and a fresh coat of paint and the house looks brand new again.

So I'm back to thinking about cedar for my next build...

Mike...

Mike, I hope you're right.

Siding on an old house usually lasts a long time not so much because of what species the siding is made of (though heart Cedar is rot resistant) but because of how it is applied so it can quickly shed water, and more importantly, how air can get the the back side to dry it out quickly.

If you go the Cedar route because you want/expect longevity, be sure to specify Heart Cedar, or you may well end up with less rot resistant sapwood.

http://www.wrcla.org/cedar_products/ced ... grades.htm

http://www.mastercodeprofessional.com/p ... r_2008.pdf

Rob

[JP8/F34]

Im sorry for your loss, I know everyone will all be out doing a 100% check on their trailers this weekend. this is a great learning tool for me know that I am just starting to build. I think adding adding metal to the roof is the way I my go. I also notice from your first line of your first post that you have already decided to build again. Let the madness begin . along with lots of photos and great ideas

[Wobbly Wheels]

FWIW, red cedar is a good choice that has been used as coring in race boats for a long time. It's light weight, its porosity means it works great with resins and sealants, and being wood it can flex infinitely without failure.
This is one that I worked on the construction quite a while ago. It's foam core and all of the hardpoints (wherever you see anything attached to hull or deck) are Western Red Cedar, just like your siding except clear (no knots). This was a $3M boat when we built it and the NZ designer had access to design with the best materials in the world, regardless of cost.


This is the 'production' version of that boat. The redesign was commissioned by the woman who completed the first solo nonstop circumnavigation by a woman...and she built the boat she did it in !
It too has cedar - the hull is cored with cedar planking.


It's all about how you treat your wood.....

[rowerwet]

Hi, my name is josh and I'm addicted to the smell of fresh plywood sawdust, in fact I like to open the door to my TD and just inhale a good wiff of that raw plywood smell every so often....so you know why I think wood is the only thing to make TD's, boats, houses, etc. out of. I used the sort of better luan, Sureply (with the black x's stamped on one side), seeing this makes me happy I covered my TD with canvas impregnated with porch and floor paint. I used only PUpremium poly construction adhesive and made sure all my seams were watertight, just like the seams on the boats I have built with the same supplies. hope your next TD is even better

[Pottercounty]

Okay, I'll try to answer the questions...

Had I noticed it before. Well last weekend I noticed the paint was all bubbly. I didn't realize the wood was delaminating.

Do I think Marine Plywood would have been better? Yes I do. But I am convinced a membrane of some sort is essential to seal off the endgrain. Membranes include canvas, fiberglass, aluminum, pvc, tpc etc. I don't think paint or uniflex can be considered a membrane. Would have epdm helped? Only if you could have sealed it properly.

I get to thinking about my house. It is covered with Western Red Cedar siding. And then it's painted. It was built in 1930, and looks as good today as the day it was built. (You know what I mean!) So I need to learn something from those guys. Goldcoop has a cedar teardrop... It still looks good too!



Mike...

I always seal the plywood ends on my birch ply with epoxy..never fails if you do a complete job...