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Discussion Starter #1
I'm stripping my roof, and got to the new addition where I discovered that the contractor cut corners and used 1/2 inch plywood for the roof deck. When I pried up the shingles, the plywood sagged, and cracked. No water damage, and the plywood looks new.

My question is can I add a second layer of exterior grade 1/2 inch plywood to add strength, or do I have to strip off the 1/2 inch, and put down 3/4?

Thanks.

Emmett
 

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Box Builder
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Are your rafters 16" oc or 24" oc? If you are going to double it up i wouldn't use anything thicker than 1/2". Around here, 5/8" is standard for roof decking.
 

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1/2" Ply is above minimum code here.
 

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1/2" and 5/8" is standard and premium. Last time I saw thicker it was usually tongue and groove solid wood on 18th century homes.
 

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I'm stripping my roof, and got to the new addition where I discovered that the contractor cut corners and used 1/2 inch plywood for the roof deck. When I pried up the shingles, the plywood sagged, and cracked. No water damage, and the plywood looks new.

My question is can I add a second layer of exterior grade 1/2 inch plywood to add strength, or do I have to strip off the 1/2 inch, and put down 3/4?

Thanks.

Emmett
There is no way this isn't a homeowner.
Such an elementary question
 

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1/2 over 1/2 works for me

start with a 24" rip so your horizontal rows are offset and be sure to break on and nail into the rafters
 

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When I pried up the shingles, the plywood sagged, and cracked. No water damage, and the plywood looks new.


Emmett
If there was a moisture problem under the plywood,it may be compromised.Check to see if the interior side of the plywood is black.
No sense adding another layer if there's not enough ventilation or other moisture problem.
 

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I'm stripping my roof, and got to the new addition where I discovered that the contractor cut corners and used 1/2 inch plywood for the roof deck. When I pried up the shingles, the plywood sagged, and cracked. No water damage, and the plywood looks new.

My question is can I add a second layer of exterior grade 1/2 inch plywood to add strength, or do I have to strip off the 1/2 inch, and put down 3/4?

Thanks.

Emmett
I stripped my walls and found out my electrician cut corners and used 14 gauge. No fires but the wires look new. Should I add more wires out or put thicker wires in?
 

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Nothing wrong with using 1/2" ply even on 24" O.C... Definitely wouldn't say any corners were cut. 7/16" OSB is questionable but I'd still consider it a proper job. I've used 5/8" T and G a few times and that makes an extremely solid roof. 3/4" would be a waste and an unnecessary safety issue to install in almost all cases.
 

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Discussion Starter #17 (Edited)
Thanks to all those who posted intelligent, helpful advice. It's very much appreciated.

To all the jerks out there, I know a great urologist who is very skilled in phalloplasty. He might be able to achieve wonders with y'all.
 
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