Deer stand plywood not lasting a year?

[Greenheadless]

I am at a loss here. I have been using 1/4 plywood (not OSB, not Luan) on my deer stands and they have not bee lasting a year. The plywood is cut to fit the tube steel frame, primed and painted well to make sure the plywood is sealed with semi-gloss exterior paint (special notice to make sure ends are sealed as well). It is screwed to the stand with a dollop of silicon on each screw and they each seam is sealed with more silicon.

Within about 8-12 months each time, the plywood start sprouting a fungus and it rots out shortly afterwards. This has happened with two stands not over a period of a couple of years. The ends are still in good condition, the mold substance sprouts all over the sheet of plywood and grows they the paint finish.

I am hunting in SE Texas, so the environment is VERY humid most of the time.

Anyone having this same issue or have any suggestions?

[Phdan]

Originally Posted by Greenheadless

I am at a loss here. I have been using 1/4 plywood (not OSB, not Luan) on my deer stands and they have not bee lasting a year. The plywood is cut to fit the tube steel frame, primed and painted well to make sure the plywood is sealed with semi-gloss exterior paint (special notice to make sure ends are sealed as well). It is screwed to the stand with a dollop of silicon on each screw and they each seam is sealed with more silicon.



Within about 8-12 months each time, the plywood start sprouting a fungus and it rots out shortly afterwards. This has happened with two stands not over a period of a couple of years. The ends are still in good condition, the mold substance sprouts all over the sheet of plywood and grows they the paint finish.



I am hunting in SE Texas, so the environment is VERY humid most of the time.



Anyone having this same issue or have any suggestions?

Paint?

[Greenheadless]

Originally Posted by Phdan

Paint?

You asking brand? If so, Behr from HD.

It is almost like the plywood has this fungus in it or is bad. Not sure though seeing it is happening on multiple stands over a multi year period, so I think I can rule out a bad batch of plywood. (As we had thought the first time it happened).

[Hooverfb]

Are you actually putting a finish on it or just a paint?painting and leaving outdoors? Wonder if the product you're using is trapping moisture inside, or just isn't sealed well enough.

[Greenheadless]

Originally Posted by Hooverfb

Are you actually putting a finish on it or just a paint?painting and leaving outdoors? Wonder if the product you're using is trapping moisture inside, or just isn't sealed well enough.

Priming then painting with 2 coats of paint and allowing to dry outside. We pay close attention to making sure the plywood is sealed. The fungus seems to just bloom from out of the plywood.

[Hooverfb]

I'd consider using some oi lfinish to displace moisture, then paint, then maybe just one coat of polyurethane or something to make sure it's really sealed (you can spray paint it later). Fungus needs moisture to grow so it's breathing in enough somehow.

[CSanders]

Treated plywood?

[sendit]

Been using 30lb felt paper over 1/2" CDX/sheathing to protect it from the rain, sun etc. on deer blinds for long time. This past season I moved a blind that I built 25 years ago and the plywood has yet to see the elements. Still going strong, I don't think there is a paint made that will protect the wood like felt paper does.

[Palmetto]

easy fix. use treated, or smart board.

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[Greenheadless]

Not treated. It has been impossible to find 1/4” treated and any thicker than 1/4” and the stands are too heavy to easily pull up and down.

I might tray some type of deck sealer first next time, just wonder if it will hold paint well after it dries.

[bbqfan5909]

Smart board or that hardy plywood, quick using plywood on blinds.

[Pony1971]

What grade is the 1/4” plywood?

Not all plywoods use exterior glue. This could be causing the veneers to delaminate/split and hold moisture.

[125Dad]

I used 1/2” treated.

[cashcropper]

You aren't going to get longevity from 1/4". Even if its painted you can just about poke your finger through it after a year. Put some 1/2" material on that stand,trim the edges with a 1x4,caulk edges and paint.

[CSanders]

You need to use treated or it won’t last no matter what you do.

[lunatic'hunter]

THIS

Originally Posted by 125Dad

I used 1/2” treated.

[Pushbutton2]

I've been tossing around the idea or trying Plywood when I had mine.

Would Marine Plywood be a good choice?

[cva34]

Originally Posted by Pushbutton2

I've been tossing around the idea or trying Plywood when I had mine.

Would Marine Plywood be a good choice?

sure but price would kick it out

[MitchParker]

I've used Thompson's Water Sealer and it's always worked great.

[Quackerbox]

Originally Posted by bbqfan5909

Smart board or that hardy plywood, quick using plywood on blinds.

This.

I have a ground blind tucked under an oak surrounded by youpon. It gets zero sun. I think it's 5 years old this year and still looks new.

Oops paint from lowes, caulked seems with flashing over them

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[Greenheadless]

Thanks for the replies guys, unfortunately, smart siding, hardie, or anything over 3/8” ply is just too heavy for how these stands work, so I will have to look into this further.

[Greenheadless]

Originally Posted by Quackerbox

This.

I have a ground blind tucked under an oak surrounded by youpon. It gets zero sun. I think it's 5 years old this year and still looks new.

Oops paint from lowes, caulked seems with flashing over them

Sent from my SM-G930V using Tapatalk

Yeah, we tried flashing on the last thinking that would help keep the water from entering from the edges. It isn’t the ends that are the issue, it is the fungus that blooms from all over the plywood. I will try to get a picture on the latest one next time I am up at the lease.

[jaspermac]

I have had better luck with 1/4" T111 and paint it with oil based exterior paint called fence and barn paint

[MisterB]

Since the uproar about formaldehyde causing so many problems, most wood processors don’t use it anymore to preserve plywood. Therefore fungus and mold grow readily when exposed to the elements. You might consider using corrected metal cut to size as an alternative.

[toledo]

You could try the plastic bathroom wall panel but don't know how it will hold paint outside.

[Quackerbox]

Originally Posted by Greenheadless

Yeah, we tried flashing on the last thinking that would help keep the water from entering from the edges. It isn’t the ends that are the issue, it is the fungus that blooms from all over the plywood. I will try to get a picture on the latest one next time I am up at the lease.

Could you skin them while in the air ?

If not sounds like sheet metal is the only option without screwing with it each year. Foam board insulation inside

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[scotty]

We use 3/8” marine grade plywood on ours. We have a sign shop in town that sells it used for $8.00 a 4x8 sheet. It lasts forever.

We set this one up this weekend. Still needs paint.

[flywise]

cover the edges of the plywood with a plastic channel. Hardware store should have this.
Typically used as finish edging on soffit

[Greenheadless]

Originally Posted by scotty

We use 3/8” marine grade plywood on ours. We have a sign shop in town that sells it used for $8.00 a 4x8 sheet. It lasts forever.

We set this one up this weekend. Still needs paint.

Dang, that’s a deal right there.

[dbaio1]

We gave up using 1/4" plywood years ago. Just too much work and it just doesn't last. No matter what we tried. Nothing but treated wood and our stands last 10 years + some.much longer.

[JHT]

Originally Posted by Greenheadless

Thanks for the replies guys, unfortunately, smart siding, hardie, or anything over 3/8” ply is just too heavy for how these stands work, so I will have to look into this further.

If your having to replace them every year wouldn't the extra effort to use 1/2 that will last for years be worth the initial headache?

[sharkhunter]

Most 1/4” is not rated for outside use. Go with a 1/2” siding like T111 or a treated product. If you plan on painting the treated your going to need to let the treated dry for a long time in the sun first.

[AgHntr10]

Originally Posted by scotty

We use 3/8” marine grade plywood on ours. We have a sign shop in town that sells it used for $8.00 a 4x8 sheet. It lasts forever.

We set this one up this weekend. Still needs paint.

That's a steal!

[Smart]

Really odd for sure. I have 4 stands skinned with 9/32' regular plywood built in 2008 and 2009 and all four are still going strong. We repaint with semi-gloss exterior paint every 4 years. None of them are showing any signs of rotting or going bad. Of course we are dryer than you are but still we have been getting a lot of rain the last 4 years. One year is **** poor and Behr is a quality paint.

[SaintBlaise]

Hey there, the lumber just can't handle the sun exposure and humidity. Time for something else. I saw here on TBH a few months ago, a blind being build from the ground up. What he did may be your solution, and save you time and money over the long haul. He built a metal frame, plywood exterior, insulated the interior and added plywood. Then added sheet metal to the exterior on top of the plywood. That will last forever anywhere. If you searched the Green Screen, you may be able to find the member if you are interested in sheet metal he used.

[Smart]

Originally Posted by SaintBlaise

Hey there, the lumber just can't handle the sun exposure and humidity. Time for something else. I saw here on TBH a few months ago, a blind being build from the ground up. What he did may be your solution, and save you time and money over the long haul. He built a metal frame, plywood exterior, insulated the interior and added plywood. Then added sheet metal to the exterior on top of the plywood. That will last forever anywhere. If you searched the Green Screen, you may be able to find the member if you are interested in sheet metal he used.

The plywood exterior is what seems to be giving him the problem.. sound like it could mold behind the sheet metal.

[Greenheadless]

Thanks for the replies guys. I will try to remember to pos5 up what is decided.

[Electrican]

Use the smart board plywood. Be sure to caulk and paint all the ends and it will last for years.

[Double-O-Dave]

I'd prime using Kilz:

http://www.kilz.com/primer/kilz-original

I'd put several coats of Kilz down first, and then paint with a high gloss exterior grade paint. Finally, I'd use the plastic (or aluminum) channel that Flywise referred to over the edges to seal them.

Good luck,

Dave

[Shinesintx]

I use cedar boards and no paint. The four corner posts are cedars that I cut and the floor is treated 2&6 pine. No issues.

[Abctx]

I know you want to go as light as possible, and think the SmartSide is too heavy, but it's actually relatively light compared to regular plywood, and only 3/8" thick.

[Throwin' Darts]

Originally Posted by Abctx

I know you want to go as light as possible, and think the SmartSide is too heavy, but it's actually relatively light compared to regular plywood, and only 3/8" thick.

This. If you think LP Smart Side is too heavy then you haven't picked up a piece

Slap some Smart Side on and be done. Think of all the money you'll save on paint over the years

[krisw]

I would use tin for the exterior and insulation board on the inside.

[Native Texan]

If it needs to be very light use Coroplast. Get the outdoor rated stuff and it will last MANY years. Lightly sand it and paint with Krylon fusion paint.

I have some stands going on 10 years made from it.

[Antlers86]

Camo R-Panel

[Spearchunker]

Originally Posted by Greenheadless

Thanks for the replies guys, unfortunately, smart siding, hardie, or anything over 3/8” ply is just too heavy for how these stands work, so I will have to look into this further.

There is a 1/4 marine grade out there

[SCREAMINREELS]

Originally Posted by Greenheadless

Not treated. It has been impossible to find 1/4” treated and any thicker than 1/4” and the stands are too heavy to easily pull up and down.

I might tray some type of deck sealer first next time, just wonder if it will hold paint well after it dries.

Use Marine grade or sign board . Talk with sign makers in your area can usually buy old ones cheap with vinyl coverings (think new neighborhood home for sale signs) they leave up for years.thats all we build out of

[cbd10pt]

I assume you are painted inside and out.

Stop

Only paint the outside, you're trapping moisture in the plywood it needs to breathe on the inside

[canny]

Based on your description you have taken a lot of steps to really seal the wood using the silicone and such. Could it be that your stand is sealed too much and its causing moisture to be trapped on the inside? If you think this is the case try adding a vent on 2 sides at the top. put a piece of window screen behind the vent to keep creepy crawlers out, but still allow the stand to breathe.

[Triple 000 Buck]

I've used an MDO plywood that i got from a sign shop, but it wont hold up to what I've seen so far of the Smart siding.
My next blind will be Smart siding and i don't believe i will ever have to rebuild it again period!