Roof Sheathing?

[karoc]

Here go again, ok while getting price on zip for ext wall I ask about 5/8 zip for roof which I also need 90 sheets. Price on 5/8 was at 42.00 ea which that translates to say 4000.00 figure in some taxes. That price is another hard pill to swallow plus zip tape. Again is this worth the extra, I think 5/8 CDX cheaper but figure in that Sharkskin. Does anyone have experience with zip roof sheathing, is there a benefit to go with zip vs plywood?

 

[mike93lx]

Zip gets you dried in the day you set it. Plus the surface is grippy. It's also flat and has the nailing schedule right on it

 

[reader2580]

Personally, I couldn't see not installing a layer of underlayment under my roofing materials even though the ZIP panels don't require underlayment. It is just me, and not based on anything I know about the ZIP roofing system.

If I had an unlimited budget I would use ZIP products all around. Unfortunately, I almost certainly won't have room in my garage build budget to use ZIP products.

 

[mike93lx]

What's the premium over cdx? Are you considering commodity grade osb as well?

 

[karoc]

What's the premium over cdx? Are you considering commodity grade osb as well?

No sir, I learned about the quality of Zip OSB and cheaper grade OSB so not going to consider it. But I’m kinda old school so what works in past such as CDX is what I’m comfortable with. Put I also know that better material also adds value to house and seals it better and help make it almost maintenance free. But with metal roof if I can swing it there be 1000 more screws. Looks like 5/8 CDX is only little cheaper than Zip. Just looking for others opinions on food sheathing. Material is adding up fast. Like others have said, it’s bad time to be building.

 

[mike93lx]

I hate the stuff too, but the reality is that it generally works. The roof on my 2003 house is osb and not a single issue with the original shingles. That said, it doesn't usually go bad til it starts leaking, which won't be the fault of the osb

 

[NUTTSGT]

I know you have been talking about building so I'm guessing stick built with trusses 24" OC ?

Being in Texas, you have no real worry about snow load. Many roofs up here survive just fine with 1/2" OSB, clips and 24" OC.

Since you are in Texas, have you considered/priced foil faced for roof sheathing ?

 

[strutaeng]

Isn't ZIP the same product as OSB, with special coating? I always assumed so. Maybe I'm wrong.

From a purely structural perspective, ZIP and standard OSB are the same. Throw plywood in the list, believe it or not...

BTW, I like to call the roof "decking" and the wall "sheathing." Probably doesn't matter to anyone else anymore.

 

[mike93lx]

Isn't ZIP the same product as OSB, with special coating? I always assumed so. Maybe I'm wrong.

From a purely structural perspective, ZIP and standard OSB are the same. Throw plywood in the list, believe it or not...

BTW, I like to call the roof "decking" and the wall "sheathing." Probably doesn't matter to anyone else anymore.

Zip uses better glue and is allegedly more dense

 

[jack stand]

You can tell the difference cutting and handling/using it (zip) that it's better. The question for me is it necessary.

 

[reader2580]

From a purely structural perspective, ZIP and standard OSB are the same. Throw plywood in the list, believe it or not...

My house has plywood decking on most of the roof and an early version of OSB for decking on an addition from the mid 1990s.

I needed to replace some bad decking and sent my brother to Menards to get two sheets of 1/2" CDX plywood. I told him to tell them it is for a roof as there is 3 ply and 4 ply in 1/2" CDX. I wasn't sure which one for a roof. They wanted to sell him OSB for a roof as they never have anyone buying plywood for a roof anymore.

 

[jack stand]

If you think regular OSB is junky, today's plywood (CDX) especially 3 ply... it takes 3 guys to snap a line on it for ripping! **** lays like a potato chip and you need a man on each end to hold it flat while the 3rd guy snaps the line.

 

[Chilliwack Murray]

I wouldn't use any osb product on a roof ever again especially under a metal roof... I've just many unpleasant evenings replacing all the screws with longer ones while an unhappy family member held up blocks in the attic to screw into.

It appears the osb wasn't able to hold the screws against the expansion of the metal and nearly all got loose and allowed water in... Most of the holes won't hold a screw now hence the blocks. The plywood won't cost any more in the long run. I have a few that ended up in trusses that I haven't figured out a solution for but it's mostly waterproof again and at least it won't blow off over the winter.

Now I have the lean to and addition roof to replace fasteners on.

 

[gahrajmahal]

I know you have been talking about building so I'm guessing stick built with trusses 24" OC ?

Being in Texas, you have no real worry about snow load. Many roofs up here survive just fine with 1/2" OSB, clips and 24" OC.

Since you are in Texas, have you considered/priced foil faced for roof sheathing ?

2nd the foil faced

 

[Sumboodie]

1/2" OSB is standard for Alaska as well. 7/16" for walls. It's fine for a 50lb snow load rating.

 

[Sumboodie]

Isn't ZIP the same product as OSB, with special coating? I always assumed so. Maybe I'm wrong.

From a purely structural perspective, ZIP and standard OSB are the same. Throw plywood in the list, believe it or not...

BTW, I like to call the roof "decking" and the wall "sheathing." Probably doesn't matter to anyone else anymore.

Yes and No. Compared to Huber OSB, yes. Compared to lots of regular OSB, no... The chips are mix of hard and softwood, glues are different.
I won't pretend to know all the other brands and how they are, but I do know OSB isn't all the same, some is great, some is ****.

The stuff we get at the stores may as well be cardboard. Leave it out in the weather for a month or two and it's swelled to nearly 1.5" it's thickness and is falling apart.

 

[yelchevelle]

I have seen several of your posts, but what is it you are building? If it’s just a shop on trusses with a metal roof, could you use 2x4’s/6’s as furring strips and no decking. If it was shingles, I wouldn’t worry about 7/16 osb, but I could see a problem with screws loosening over time as mentioned above. That’s pretty critical on a roof depending on the torque of the screw to keep it waterproof.

 

[ipgenie]

I use OSB under metal roofing all the time. Screws don't go in just the OSB, they go through it into the trusses or perlins. I always use 2" screws. They cost a few more dollars than 1 1/4" that everyone seems to prefer but I've never had a roof blow off yet.

 

[larry4406]

Go old school.

• Have the framer install 30# roof felt right after he nails off the last sheet of roof sheathing.
• Use ice-guard (~36" wide roll) as first course down at facia
• Use cap nails to secure the felt; greatly increases the staying power during high winds and until its shingled. At the day job they cap nails are typically round but apparently the square ones are better (IDK)?
• Cover the open ridge (assuming you are doing ridge vent) with the felt. When they shingle they will razor knife it open.

Once framer is on the roof, take away the ladder to ensure he stays up there till its done .

Dried in right away.

Our new houses use 7/16" OSB, clips at half point between trusses, and trusses 24" on center.

 

[ddurrett896]

Huge fan of Zip, but only for walls and 5/8 ply for the roof.

Still can't wrap my head around Zip roof. What happens when the roof is replaced and inevitably scratched up during demo and needs a barrier, thus creating a place for moisture to mold.

 

[strutaeng]

I built my addition right after Hurricane Harvey, so I had to pay extra for sheathing and decking. I was buying materials slowly. I bought all the standard OSB for the walls at the "normal" price back in the Fall of 2017, pre-Harvey. A month or two later the price was way up. For an extra dollar I was able to buy 15/32 plywood for the roof deck. For the walls I used 3/4" continuous insulation XPS boards, taped joints. Then Tyvek with laps taped. I even sealed the masonry ties after the masons where installing the veneer.

It was funny because my framer was surprised I had bought plywood for the roof deck! He said he preferred OSB and hadn't installed plywood in who knows how long! I was like, "Well, that's what I bought so that's what you have to work with." LOL

My roofer sided with me on the plywood vs OSB. He said plywood was a better product based on his experience. I felt a bit better...I thought I had gone crazy with my previous conversation with my framer ;-)

 

[reader2580]

Huge fan of Zip, but only for walls and 5/8 ply for the roof.

Still can't wrap my head around Zip roof. What happens when the roof is replaced and inevitably scratched up during demo and needs a barrier, thus creating a place for moisture to mold.

How is this any different than stripping a roof with OSB? ZIP specifically states that underlayment will need to be used when the roof is replaced.

 

[strutaeng]

That's the same issue with as the zip sheathing with all the nailheads penetration all of the wrb. At least the sheathing you probably won't expose again...in your lifetime.

Roof decking on the other hand, will probably wind up with 10,000 nail holes by the second re-roof. Have you seen roofers tear off an old roof? They are blowing and going. Not gingerly.

Seems you are paying a lot of extra cash just for a "fast dry-in". I'm guessing the carpenter install the zip tape on the roof deck? It probably boils down to that vs waiting for roofer and him getting the felt on. They usually shingle the same or next day around here. Those roofers are fast.

Who's doing your work BTW? I've posted on several of your posts, but don't recall seeing that you've stated that. DIY project? Have you talked to your GC? Or if self performing, your subs?

 

[rayra]

I cannot fathom how many people seem to think Zip and OSB are same-same. Or that it isn't worth the premium.

Definitely roof with it, if you can at all afford it. Go cheap on the vertical siding if you must. But roof with Zip.

 

[mike93lx]

That's the same issue with as the zip sheathing with all the nailheads penetration all of the wrb. At least the sheathing you probably won't expose again...in your lifetime.

Roof decking on the other hand, will probably wind up with 10,000 nail holes by the second re-roof. Have you seen roofers tear off an old roof? They are blowing and going. Not gingerly.

Seems you are paying a lot of extra cash just for a "fast dry-in". I'm guessing the carpenter install the zip tape on the roof deck? It probably boils down to that vs waiting for roofer and him getting the felt on. They usually shingle the same or next day around here. Those roofers are fast.

Who's doing your work BTW? I've posted on several of your posts, but don't recall seeing that you've stated that. DIY project? Have you talked to your GC? Or if self performing, your subs?

So because the second re roof (50 years away) will have holes, the product is a waste? You just put down underlayment or redeck it. Doesn't make the value of it less

 

[strutaeng]

So because the second re roof (50 years away) will have holes, the product is a waste? You just put down underlayment or redeck it. Doesn't make the value of it less

Ok, yes. Agreed. 25 years years of OP + 25 years of the re-roof...he probably won't be around to see that. Maybe? But realistically: 5,000 nails holes on first install + 5,000 nail holes at "start" of re-roof = 10,000 nail holes is what I was assuming. Probably a "gross" assumption on my end....I don't know what the roofing nails is per square.

25 years is still a long ways...that was the point I was trying to make. More importantly, just get yourself a good roofer and you really don't have to worry about the issue. Maybe I'm missing something here?

If you re-deck at re-roof then all this discussion goes down the drain, right?

I didn't intend to imply zip roof deck is junk either...

 

[ddurrett896]

How is this any different than stripping a roof with OSB? ZIP specifically states that underlayment will need to be used when the roof is replaced.

Because there will still be some areas that aren’t 100% stripped of the ZIP coating and unless majority of it is gone, there a moisture envelope.

 

[larry4406]

If ZIP requires underlayment at time of reroof then that should figure into one's lifecycle cost comparison of OSB vs ZIP when making decision on which to use.

Or just decide to screw whomever when its reshingle time.

 

[Hank11]

20 years from now when its time to re-roof most will put a new roof over the original. If the original has to be torn off and replaced, then adding a layer of tar paper or similar approved material won't be a problem.

 

[reader2580]

If ZIP requires underlayment at time of reroof then that should figure into one's lifecycle cost comparison of OSB vs ZIP when making decision on which to use.

I doubt anyone is justifying ZIP by thinking they can save a couple hundred dollars on underlayment when they re-roof.

 

[reader2580]

20 years from now when its time to re-roof most will put a new roof over the original. If the original has to be torn off and replaced, then adding a layer of tar paper or similar approved material won't be a problem.

Where I live it is very uncommon to put on a second layer of roofing. There is almost always a tear-off done before installing the new roofing.

 

[manwithtools]

20 years from now when its time to re-roof most will put a new roof over the original. If the original has to be torn off and replaced, then adding a layer of tar paper or similar approved material won't be a problem.

This may not be as common in the future as the architectural shingles of today are going to be hard to roof over compared to the 3n1 tabs of old.

 

[billconner]

Where I live it is very uncommon to put on a second layer of roofing. There is almost always a tear-off done before installing the new roofing.

Interesting. In Chicago burbs 2 or 3 layers were common.

 

[65ranchero]

Interesting. In Chicago burbs 2 or 3 layers were common.

3 Layers?
Seems like asking for trouble for snow load issues.
My guess is the roofers can install it for less money to the consumer because there is no disposal fees.

 

[mike93lx]

I will always do a full tear off. How else do you make sure that the sheathing is in good shape and get the most nails in the lawn?

 

[billconner]

3 Layers?
Seems like asking for trouble for snow load issues.
My guess is the roofers can install it for less money to the consumer because there is no disposal fees.

I believe the span tables for rafters account for 3 layers. Besides, shingles may be 2 to 5 psf, and snow load in my area is 60. Another 6 or so psf is not significant. Buildings built to code are just not that close to failure.

I reroofed my 1904 house in 90s, 33 square. Tore of 3 layers (first was original cedar shingles,) on skip sheathing (before installing 1/2" cdx, and 40 year architectural shingles - all solo)