# Painted OSB Sheathing as Siding?



## Beginningwoodworker (May 5, 2008)

I am planning on starting the repairs to my 10×12 shed,I am going to start by jacking it up. I have a painted OSB on the shed, I am wondering would painted OSB will hold up? I have some rot on the bottom that needs cutting off because water got in the shed.


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## FirehouseWoodworking (Jun 9, 2009)

OSB would not be my first choice. Any portion of OSB, such as the bottom edge or the backside on any overhangs, that is not sealed and/or painted is destined to fail and rot.

Pretty much the same for any manufactured wood product and even natural wood that is not naturally rot resistant such as pine.

It all comes down to the old adage: "Think like water." If water can migrate to any portion of the siding that is unprotected (sealed, painted, caulked, etc.) it is destined to fail. And of course, that implies failure to conduct routine maintenance. Caulking never lasts forever. Occasional repainting is necessary. Good luck!

Cheers!


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## richgreer (Dec 25, 2009)

You can buy pressure treated plywood. It is intended to hold up to weather. In this area I have found that it holds up reasonably well for about 10 years. You should not paint it until it has aged a couple of years. It is probably your best low cost option for siding that is weather resistant.


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## Beginningwoodworker (May 5, 2008)

I thought about making my own siding!


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## lew (Feb 13, 2008)

I agree with Dave.

Covered my garden shed (10×12) with OSB many years ago and kept it painted. That didn't stop it from expanding, rotting and generally coming apart. If I were to do it again, I'd use something else.

Lew


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## jack1 (May 17, 2007)

No, no, a million times NO! In one year (if you're lucky) you'll be using all those words we re not supposed to use with mom around. It's only for under t-11 or some such.


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## Beginningwoodworker (May 5, 2008)

It done started rottening on the bottom, since the shed is on the ground. In a few weeks I am planning on jacking up the shed and put on two 4'' soild concrete blocks and replace the flat roof with a gable roof.


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## MoshupTrail (Aug 11, 2011)

I agree with jack1 - absolutely NOT! unless you can find exterior graded OSB, like they put on roofs in some places. The problem is moisture will quickly degrade the glue and your OSB will begin to expand. As the layers spread they will hold more and more moisture leading to rot within a few years, depending on weather. And yes, that's even when painted.


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## a1Jim (Aug 9, 2008)

OSB would not be my first choice but I've had pieces of it laying on the ground for two wet winters and not degrade. Don't confuse OSB with partial board,Osb has much more resin in it than partial board . OSB will expand some but not fall apart because of it. If your budget will allow Charles I would go with Ply or T111 ,if you use OSB pre-paint it.


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## Beginningwoodworker (May 5, 2008)

I already have painted OSB on the shed, the top part is not rotten. I cant afford new siding at the momment. Just another coat of paint.


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## Clarence (Nov 23, 2009)

Regardless of how long OSB lasts, it will always look like OSB.


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## Roz (Jan 13, 2008)

Hi Charles, I don't like or recommend OSB for exterior siding. However, I have a cousin whose builder used it on an extension to her house and then covered it with battens and painted it very well. It has been there now over 20 years and is still looking good. You have to keep it painted and well away from contact with soil. If you are looking for an inexpensive siding I would consider 4X8 Masonite panels which have to be treated in much the same way.


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## Grandpa (Jan 28, 2011)

I go by a building and standards book when inspecting homes. It states that wood siding should be 12 inches (minimum) from the soil line. We don't see that often but that is what the books says.


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## Grandpa (Jan 28, 2011)

Ditto on what Steve said. It also comes with a paint or stain on it that has a 40 or 50 year warranty. I don't like to paint.


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## Beginningwoodworker (May 5, 2008)

Hardiplank siding is around 7 to 8 bucks at the home center. need around 56 peices thats $300 to $400 bucks!


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## Grandpa (Jan 28, 2011)

It can be bought around here from Lowe's for about $6 on sale. It might never go back to that but that has been the past history. With that said this is a better product and you do pay for the extra life but in the long haul it will pay you back. You can cover it with OSB every few years and that will add up too. You have to decide where your budget will allow you to go and where you want to go.


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## Beginningwoodworker (May 5, 2008)

I got other things that needs to be done to the shed first like jacking up the floor and replaceing the flat roof.


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## 747DRVR (Mar 18, 2009)

I used T1-11 to build a 10×12 shed 8 years ago and it still looks new.Held up to 3 hurricanes.


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## ssnvet (Jan 10, 2012)

I build my 16×8 shed sitting on cinder blocks laid loose on the ground and sided it with 3/4" T-111 over 2x studs some 20 years ago…

I put one coat of stain on it way back then…

I've moved the shed twice since, the last time landing it on concreat block pylons on concrete footing 3' below 
grade.

The shed isn't pretty, but it is solid and the only rot in the T-111 is at the bottom of the door, where water splashes up from the steps.

Now that it's found it's permanent home, I'll probably slap some surplus clapboards from our house addition and paint it to match the house.

T-111 if you want to paint/stain the sheathing and call it good.

If you want to side it, use 1/2" plywood….. or if you want it to last forever, use Advantech.


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## Beginningwoodworker (May 5, 2008)

Thanks guys I am thinking about using HardiPlank Lap Siding or LP Smartside Lap Siding!


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## Stinkey (Oct 20, 2015)

I have some old 3/8" plywood, will that be safe to use as siding if I paint it thoroughly?


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## rwe2156 (May 7, 2014)

There is a reason its covered with shingles or siding ;-)

BUT,

OSB does, in fact, have some ability to withstand moisture.
I"ve seen it on the sides of barns with no paint at all last for years and years.

I think if you made sure all the edges and seams were throughly sealed it would work as long as its a vertical application.


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## MT_Stringer (Jul 21, 2009)

You can do it right the first time or you can do it over a second time. I think you are approaching the second time fast. T-111 siding for the walls and 2 coats of paint and you would be good to go. That is what I used on my 10×12 storage shed when I built it in 2002. It still looks like new.


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## SignWave (Feb 2, 2010)

> Thanks guys I am thinking about using HardiPlank Lap Siding or LP Smartside Lap Siding!
> 
> - Beginningwoodworker


Other than the surface texture, I have a hard time seeing how LP Smartside is different than OSB.


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