Osb longevity

[dclynch]

I build all my sheds with OSB. I pait both sides and I currently have one going on 8 years with no signs of needing to be replaced.

 

[like2wheel]

"I bought some on a humid day, & by the time I got home all that was left was sawdust in the back of the truck"
:laughing:

Seriously, for vertical surfaces, it'll be fine. Paint or use a penetrating stain/sealer.

If you overbuild it, you're sure to find a better hunting place next year...

 

[Oliver1655]

My vote is for marine plywood. Not to be confused with treated plywood.

Another possibility would be to use steel/tin. I have re-used old tin on vertical surfaces rarely have noticed a leaking problem.

 

[newbury]

At about 15 to 30 bucks a gallon for paint, it doesn't take much to make up the price difference to a marine grade of plywood that will last years and years without any paint. I never liked OSB as I always found that small pieces always de-laminate and turn into large splinters ready to injure you.

Home Depot - Marine plywood 3/4" $70 ON THEIR WEB SITE
OSB - $15

BUT TRY TO FIND MARINE PLYWOOD!!

I wanted to use marine plywood for building some boxes that I plan to use to haul stuff for decades. In Northern Virginia NONE of the regular lumber yards OR the HD's or Lowes would order it. And I called several marinas. I found one "specialty" shop, referred by a marina, that sold it - $110/sheet! And that was if I ordered 5 sheets.

I have to agree with Gary the Marine plywood is the way to go.

IF you can find it!

I've seen OSB scrap get ruined by rain in a few weeks. On the other hand, I have had regular old 15/32" plywood side boards on my trailer for 7 years now. It turned gray, but is still holding up OK and functioning fine. It was scrap, so I figured no big deal if it only lasted a little while, but it's far exceeded my expectations.

By the time you paint/treat OSB, you may as well have gone with plywood to save time/money.

PT plywood will last for years with a little paint.


I've built a lot of stuff with PT plywood that lived outside with minimal protection, 2 layers of WHOOPS paint, seal the edges, lasts for years. I tried OSB with the same treatment. But with OSB if you get a break in the paint ANYWHERE it just sucks in moisture and delaminates. Nail, screw holes are the worst. With a little normal flexing you get a hole.

I'd say use marine plywood IF you can get it at a reasonable price. PT with a little maintenance is good, OSB requires a lot more careful maintenance.

Now if ANYBODY knows where I can get a good marine plywood near Alexandria Va. for <$70/sheet of 3/4" x 4' x 8' I'd like to know.

Until then I'm stuck with PT at ~$40/sheet.

* WHOOPS paint is the stuff you find at the hardware store for $3 to $5/gallon because someone returned a tinted can

 

[Walkin Horse]

Have you tried Plywood and Plastic in Richmond. I know it's not near you but close.

 

[dave1949]

A frame made of pressure treated lumber covered with roofing/siding metal might be an alternative to wood sheathing of any kind.

 

[BKBrown]

Now if ANYBODY knows where I can get a good marine plywood near Alexandria Va. for <$70/sheet of 3/4" x 4' x 8' I'd like to know.

Right now - 3/4" 4'x8' PT is $51.19 at MWP Supply in Madison, VA - it is a ways from Alexandria, but if you have a trailer to haul it with --- https://store.mwpsupply.com/departments/plywood-treated-untreated-|PW|PLY|PWPLY.html?top=0
and MWP treats their own Plywood here in Madison.

Give them a call and they may be able to get Marine Plywood for you.

 

[newbury]

Right now - 3/4" 4'x8' PT is $51.19 at MWP Supply in Madison, VA - it is a ways from Alexandria, but if you have a trailer to haul it with --- https://store.mwpsupply.com/departments/plywood-treated-untreated-|PW|PLY|PWPLY.html?top=0
and MWP treats their own Plywood here in Madison.

Give them a call and they may be able to get Marine Plywood for you.

Thanks
BUT
That's about 170 miles round trip for me when I'm in Virginia.
I only need three to five sheets
They DON'T list marine plywood https://store.mwpsupply.com/departments/plywood-treated-untreated-%7CPW%7CPLY%7CPWPLY.html?top=0
The $51/sheet PT is about $10, 25% more than what I paid from the local to me in Virginia lumber company and $20 more than what I pay down in Fulton, MS, where I'm at now (I just called - they didn't carry marine plywood either).

I still think the best bang for the $ is PT plywood with WHOOPS paint.

 

[rd_macgregor]

Are engineered wood siding panels (like those often used on backyard sheds) more expensive than marine plywood?

 

[newbury]

Which brings up another possibility.
Concrete. Hardiboard type panels. I built a shed on a 2x4 stick frame. Stuff lasts forever if you don't break it. No paint needed, but I installed it by drilling screws in.