OSB vs Plywood for Roof

[WVH1977]

Is OSB just as good as plywood for a roof on a new house? Also, would y'all be ok with 24" on center trusses or rather have 16" on center. Is 24" OC going to cause issues down the road? Is it worth the extra coin to go 16" OC with plywood vs the 24" OC with OSB?

Thanks in advance for any responses.

 

[Deere Dude]

24 oc with 1/2 -osb works with shingles and drywall. but, 16 OC is better.
Depends on code in area but 24 works. Never had any problem with osb even though I was hesitant doing my first house with it.

 

[Rustyiron]

Richmond VA with (virtually)no snow load, sure, but don't forget the "plywood clips".

 

[RNeumann]

Truss packages are all engineered for span and sheathing thickness. No issues with 24” OC if it has been engineered that way! If you are concerned Simpson makes a little clip called an H1. It can be had in 1/2” and 5/8” if I recall. That will help with sheathing.

OSB and plywood is like Ford vs Chevy- just not as old. The glues have improved enough in OSB that it’s stable and does fine with moisture. Plywood obviously has a long history and does good with moisture.....until it doesn’t. When you get a little delam you will see that in the roofing. That said my current roof has plywood- I wasn’t the contractor and that was his choice. Everything else on the house is OSB- go figure!

 

[Gary Fowler]

Seems I read somewhere that OSB is actually stronger than plywood given same thicknesses. OSB is all I ever see used on roof sublayer.

As for spacing, I would go for 16" O.C. An extra truss every 4 feet isn't going to cost a lot more $$ unless you are talking a HUGE building.

 

[/pine]

Most residential trusses are designed for 2.0' OC installation...plywood clips are usually required for sheet decking 1/2" or less...(clips not required for 16" OC trusses/rafters etc..)...

With OSB there can be less waste due to no grain orientation...OSB is less friendly than plywood for marking and cutting cleanly...

16" OC framing makes for flatter ceilings...Often with things like veneer plaster ceilings with 2' OC trusses are stripped with 1x3s etc. on 16" oc...

 

[Tractor X]

24" requires plywood clips and drywall can get wavy without blocking. it doesn't cost that much more going 16 vs 24 oc.
when OSB 1st came out we called it "other $hits better"... still call it that today!
lm stick building my house with 3/4" wood decking, ice/water shield and 26ga metal... go plywood!

 

[stuckmotor]

A friend of mine built a porch onto his mobile home using rafters on 24" centers. Pretty soon, he got a cease and desist letter from the county. The building inspector wanted them closer together. I never heard how things worked out.

 

[Industrial Toys]

I only use plywood. I see OSB as garbage, but realize it has its place in the world and does a good job. I have done several outbuilding roofs, and the plywood is so much nicer to look at.

 

[aczlan]

I only use plywood. I see OSB as garbage, but realize it has its place in the world and does a good job. I have done several outbuilding roofs, and the plywood is so much nicer to look at.

From what I understand, the advantage of using OSB for roofs is that a smaller/thinner "chip" blows off of the back when you put a nail through it vs plywood, as such, with 1/2" plywood, you may have 3/8" of thickness where the nail goes through for it to grip whereas 1/2" OSB still has the full 1/2" or at least 7/16" for the nail to grip.

Aaron Z

 

[polkwrangler]

I had my house built in 2008,they used foiled covered osb for sheathing worked out great..lay foil side facing down though

 

[mikester]

OSB is used because its cheaper than plywood. End of story. The only thing worse than OSB is MDF. Builders would use 1/4 inch MDF if they could but that stuff has zero structural integrity.

The biggest problem with any of these materials is moisture. Plywood is the most moisture tolerant of the three, MDF the least. Wet plywood de-laminates. Wet OSB crumbles. Wet MDF turns to porridge. Plywood will have structural integrity, hold fasteners better and longer than OSB ever will. Wet wood is still stronger than wet glue.

Eventually all roofs leak.

If you plan on flipping the home or moving in the next 5 years use OSB because it’s cheaper. If this is your forever home go plywood and you will thank yourself later.

 

[Oldoak]

Everyone has their own preference and in many, but not all areas, a building code that must be adhered to.

On our new house that we had built just six years ago, I specified 2x6 trusses, 16" on center and 5/8" plywood for the roof construction. And 2x6 studs, 16" on center and 1//2" plywood for the exterior walls.

 

[newbury]

OSB is used because its cheaper than plywood. End of story. The only thing worse than OSB is MDF. Builders would use 1/4 inch MDF if they could but that stuff has zero structural integrity.

The biggest problem with any of these materials is moisture. Plywood is the most moisture tolerant of the three, MDF the least. Wet plywood de-laminates. Wet OSB crumbles. Wet MDF turns to porridge. Plywood will have structural integrity, hold fasteners better and longer than OSB ever will. Wet wood is still stronger than wet glue.

Eventually all roofs leak.

If you plan on flipping the home or moving in the next 5 years use OSB because it痴 cheaper. If this is your forever home go plywood and you will thank yourself later.

Unless you go with a quality OSB like AdvanTech and compare it to run of the mill big box hardware store plywood.

I've gotten plywood from Lowes and Home depot that delaminated slightly, then when I look inside there were massive voids. So on 5 layer plywood I would find a "decent" surface layer, a voidy second layer, etc. Sometimes a "knot" on the surface layer would line up with a void underneath.

OSB is solid when made and I've seen the AdvanTech sit out in the rain for months. But the darn stuff is HEAVY. Unlike PT plywood it does not get lighter with age.

"Old timy" OSB used to crumble quickly. Throw a fresh piece off the porch in the rain and it would crumble before it hit the ground

 

[fried1765]

From what I understand, the advantage of using OSB for roofs is that a smaller/thinner "chip" blows off of the back when you put a nail through it vs plywood, as such, with 1/2" plywood, you may have 3/8" of thickness where the nail goes through for it to grip whereas 1/2" OSB still has the full 1/2" or at least 7/16" for the nail to grip.

Aaron Z

That is a new theory for me!
In my opinion, OSB is only better on the wallet!
Cheap junk!!

 

[TMGT]

I recently had a lot of experience with OSB while building my shop, before building I also had my reservations with OSB from past experiences.
I will say there have been a lot of improvements to OSB over the previous stuff, and a decrease in plywood. I would put them about equal for modern 7/16-1/2 sheathing with the OSB being less expensive, also you have the advantage of consistent density with the OSB where you will hit voids with the plywood when nailing.

Only thing I dont like about OSB is cutting it (the sawdust gets everywhere and always in my eyes) and you have to be a little more careful with the corners/edges.

Then theres advan-tech, it's in a class of its own!

 

[Sawyer Rob]

Personally, I prefer plywood, there's no doubt it's better... Ply is better if the roof has a leak later and better with 24" rafter spacing for less sag ect...

That doesn't mean OSB won't work, but it has to have the nails set perfectly! Any nails going below OBS' surface and you loose a lot of the holding strength, not so much with plywood.

IF I had the money, I'd go with ply every time...

SR

 

[3Ts]

Then theres advan-tech, it's in a class of its own!

Agreed! But even if you specify that particular brand, the chance is good that the lumber yard will ship some other brand and claim it's just as good, but it's not. I've used it for sub-floor and it's better than anything else on the market.

 

[Tractor X]

Everyone has their own preference and in many, but not all areas, a building code that must be adhered to.

On our new house that we had built just six years ago, I specified 2x6 trusses, 16" on center and 5/8" plywood for the roof construction. And 2x6 studs, 16" on center and 1//2" plywood for the exterior walls.

well built house right there!!!

 

[nybirdman]

As far as sheeting;ZIP board is the "go-to" in our area.They make if for side walls and roofs.