# OSB under rubber roof ?



## Worm Drive (May 2, 2007)

I'm having a new rubber roof put on our addition and noticed the contractor has a stack of OSB leaning up against the house. Is it an acceptable substrate under a roof, I've always used cdx plywood?


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## johnk (Apr 23, 2007)

Its not my personal preference but yes its acceptable,at least where I'm from.


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## Slyfox (Dec 22, 2007)

johnk said:


> Its not my personal preference but yes its acceptable,at least where I'm from.


 
Same in my area.


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## Jake Stevens (Dec 10, 2007)

Same for us. But maybe it's Advantech. Ask him. We don't use pylwood at all anymore.


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## BKFranks (Feb 19, 2008)

Read the entire report from the National Roofing Association​http://www.nrca.net/rp/technical/files/7141.pdf


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## MALCO.New.York (Feb 27, 2008)

Certainly! What/how much insulation on top of the OSB is the pertinent question.


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## RooferJim (Mar 6, 2006)

I would never recomend OSB for roof sheathing. I have seen the horror stories first hand. Use Plywood.


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## 2ndGen (Apr 6, 2006)

Never...just because it's "accepted", I' never use it. Not under my own house nor on any of my customers. 

No matter what one does, water can always get into a house. 

If you have OSB, you're dead! 

No way. Mark my words, OSB will not be allowed to be installed for roof sheathing one day.

It's just not worth the $4. a sheet difference. 

Plywood, plywood, plywood.

Torchdown roofing was once "okay" too...once.


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## johnk (Apr 23, 2007)

Torch-on Is still huuuge out here.


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## thom (Nov 3, 2006)

I like osb better than ply. 

moisture is not much of an issue out here in Albuquerque. OSB seems to hold up better. Ply seems to delaminate.


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## MALCO.New.York (Feb 27, 2008)

I like-a-da-torch. I like-a-da-plywood.


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## RoofGod (Mar 21, 2008)

If its screwed not nailed and doesn't leak it will be fine.


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## 1967 chevell (Mar 20, 2008)

BKFranks said:


> Read the entire report from the National Roofing Association​
> http://www.nrca.net/rp/technical/files/7141.pdf


 
Intesting report from that particular study, I believe that the preparation work has to be done properly, ventilation, flashing, ect. If this is such a large concern, why are we using junk I beams for floor joists vs. 2x12s. I suppose cost as well. Search the UL website for videos on how quick this joist fails under a short fire load. Being a firefighter instructor and paramedic for almost 15 years, anything will fail under less that ideal conditions.


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## Worm Drive (May 2, 2007)

Thanks for the replies. I'm going to talk with the contractor about using plywood instead.


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## 2ndGen (Apr 6, 2006)

thom said:


> I like osb better than ply.
> 
> moisture is not much of an issue out here in Albuquerque. OSB seems to hold up better. Ply seems to delaminate.


I could see that out there. 

When I was a Super for a production roofing corp in Arizona, the tract houses were sheathed with OSB, 
but the edges (about 16-24" in) at the perimeter of the roof (eaves & rakes) were all done with plywood because if they got wet, they'd hold up better. 

The problem with OSB is that "if" it gets wet, there's no fixing it or dealing with it. It has the be ripped down t the rafters and completely rebuilt. 

I guess that won't be a problem out in the SouthWest. 

In the NorthEast...it's a big problem.


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## 2ndGen (Apr 6, 2006)

Worm Drive said:


> Thanks for the replies. I'm going to talk with the contractor about using plywood instead.


It's better to be prepared for a situation that never arises than for the situation to arise and one "not" be prepared for it. 

Again, the price per sheet is nothing when you consider the peace of mind it will offer you. 

Besides, ply is lighter and easier to cut and to work with. And it can get wet if you get caught up in a sudden storm. 

:thumbsup:


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## MALCO.New.York (Feb 27, 2008)

I worked for Bryant-Universal Roofing a couple of times when I lived in AZ!


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## adcoleman (Oct 3, 2008)

I always use 5/8" TG Advantech, its better than OSB and plywood


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## JT Wood (Dec 17, 2007)

without a word of a lie, In the last 10 years I have only seen 5 or 6 houses using plywood sheathing on the floor, wall or roof. It's ALL osb here.


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## MrRoofer (Sep 21, 2008)

OSB under rubber is ok here too. It's also pretty rare to find a plywood house here, not to mention this neck of the woods is generally pretty arid as well. Poofy OSB aside, any wood that is allowed to get wet is a bad idea. Check your local codes and regurlations _and,_ maybe a climatologist will help decide which materials are appropriate for your situation.


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