My builder is essentially over-building the framing on our new house – which I am not complaining about. However, he started the roof decking over the weekend and is using 15/32″ plywood. Rafters are 16″ on center. Roof will architectural composition shingles. I know this is OK for code, but wouldn’t I have a much better roof (better stiffness and nail holding) with 5/8″ plywood?
I am not pushing back on other things, but I feel strongly about this. Am I being reasonable? If he comes back with additional charges, what would be the differential in cost to go from 15/32″ to 5/8″?
Thanks!
Replies
We need to build roofs here for 85 psf ground snow load, and the typical framing is 24" on center, with 5/8 OSB decking on that.
You have 16" centers, and a whole lot less snow load. You'll be fine with 1/2 inch decking. There is plenty of it used all the way down the coast and around to the Gulf of Mexico, where the roofing mostly stays on during hurricane seasons.
Now go and splurge on some nice copper roof flashing, with the money you'll save on decking. Recent quotes I have, show as much as a $6 per sheet upcharge, to move up to 5/8 from 1/2.
Did the contract specify anything in regard to roof decking?
Like Gene, in my area, 5/8th is about 6 dollars more a sheet then 1/2" that does include the minimal extra time it will take to set due to weight which will slow things down just a hair.
What does the plans say?
If they say 15/32 and you want 5/8 then it will be up to him what he charges you but this should've been discussed before he started. If you want 5/8 he'll have to rip off what's there and start all over again.
Go with the 5/8 cdx plywood. Anything less is folly.Only a hack would use 1/2 in. And osb should never go on a roof.
There are plenty of places in the construction where you can safely cheap it , but the roof deck is not one of them.
Well Jay,I guess I'm a hack. I think 1/2" ply at 16" oc is sufficient.The extra money could be used more effectively elsewhere.
Jon Blakemore
I'm sorry... I shouldn't throw terms like that around so quickly. I'm sure that you do all that is required. I guess I meant say that going above and beyond what is normally required would be preferable .
Jay,You will cone to realize that everyone does things different around here. I started framing 20 years ago and all subfloors were 1/2" cdx fir with oak flooring right on top with no problems, where there was carpeting we would go back and put a 1/2" layer of under layment, now it's just 3/4" t&g glued and nailed with nothing else above it and all roofs were 1/2" fir, now we use 5/8" but there are some plans that will speck 1/2" but I wont use it I'll just put 5/8". We always frame 16" o.c. Never heard of stick framing 24" o.c. until I read these forums. Trusses 24" o.c., Yes.I've never seen anyone put osb on a roof either, let alone 1/2" but guys are doing it. I read on another forum that some guys house has 24" o.c. rafters with 1/2" plywood with no h-clips, I think that's a Hack job. But for the most part, It amazes me how we do things different but not everything is a Hack job.Joe Carola
5/8" on 16" o/c, that is un hear of here, most ( 90%) are 7/16 osb on 24" o/c and I have come across a lot of 3/8 spuce w/ 'H' clips on 24" o/c. & some withoutclips. The rare 1/2' fir plywood 16" o/c is a dream. If you quote the price to do 1/2" x 16" o/c roof system , you would get work up here! You got to be very carefull on a roof around here, you may fine yourself in the attic!
IF IT WAS EASY, EVERYONE COULD DO IT!
Joe,I've installed plenty of 7/16" OSB on framing spaced 24" oc. I wouldn't prefer to do it on my jobs but I must say it's not as bad as it might seem. Unless you have moisture problems the OSB holds up pretty well without sagging.
Jon Blakemore
I've installed plenty of 7/16" OSB on framing spaced 24" oc. I wouldn't prefer to do it on my jobs but I must say it's not as bad as it might seem. Unless you have moisture problems the OSB holds up pretty well without sagging.
Jon,
You've done this with no H-Clips?
Joe Carola
>>>>"You've done this with no H-Clips?"No, H clips are always used. I was referring to general sagging between the framing members.
Jon Blakemore
No, H clips are always used. I was referring to general sagging between the framing members.
I wonder if guys are sheathing 24" o.c with 1/2" with no H-Clips.
I think Tim Uhler does and he's the biggest HACK in the world........;-)
Joe Carola
>>>>"I wonder if guys are sheathing 24" o.c with 1/2" with no H-Clips."I'm sure some out there are doing that or worse.
Jon Blakemore
I am a pretty big hack for a guy who is 5'7" I seem bigger in real life :-)
We frame 24" oc for rafters and ceiling joists, unless the span gets really big. We use 1/2" with H-clips. Never done a roof without H-clips, BUT there is a builder, if he is still around about 30 minutes north of us that told his framing subs NOT to use H-clips. A guy I knew did work for this builder and that is how I know.
I've gone back to roofs that are 10 years old that were framed 24" oc w/ 1/2" OSB and H-clips and they still look nice and flat. We usually get the roofer there as we are finishing sheathing the roof, so it doesn't get wet for very long.
I was going to post a sign in the house we just finished framing and siding today that said "Another quality Hack job done by the A-team"
Tim,At 5'7" are you at Stallones weight of 155 pounds?http://www.sylvesterstallone.com/
Edited 3/29/2005 12:28 am ET by Framer
I haven't been that weight since I was 14!!!!
I certainly agree with you too. No problem .
Been there, done that.
That is a pretty strong statement. Mind backing that up with some logic? I'm just curious if this is just an opinion, or if you have some info? If you do, pass it along, I'd rather not be a hack all my life :-)
And they thought all the flame throwing was relegated to the Tavern now...
Man Oh Man, Us hacks are everywhere.Tee hee
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Naw, I don't throw flames. It's never worth it, BUT I definitely want the Golden Framing Axe award if one is given out :-)
Wasn't You I meant. I think it was Jay who threw the word hack out at everyone.
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It is just my opinion! It is a well earned, hard won, oft used opinion, but mine none the less.
Then again I do have a propensity for doing things the right way and not skimping on the important elements. A roof deck is just not a place where I look to save a few bucks.
Why is it 'skimping'? Would you use 3/4 ply for wall sheathing when 1/2 will do fine?
I didn't do it....the buck does NOT stop here.
Why is it 'skimping'? Why use 3/4" ply for wall sheathing when 1/2" will do fine?Framer[hacky-sack]T.
I didn't do it....the buck does NOT stop here.
that is a bold statement to say only a hack would use osb.ive been doing this for about 18 years and i have seen some plywwod sheathing apps on roofs that are pretty rank.as far as strength dosen't osb somewhat outperform plywood?--just wondering if someone out there has any tech data to check?
They both have there own pros and cons. They equal out about the same in the end.
Hardly ever see anyone using plywood on roofs around my area in North Georgia.
7/16 OSB for roof decking 3/4 Advantec for flooring.
Lots of hacks in these parts.
all i know is my gun will shoot a nail straight through some osb if i don't hit a stud.
RTC
Well, I'm a hack, too, but not an OSB hack, thank God. I'm a 15/32nd ply hack, but I'm in south Georgia which means no snow load, EVER.
And I insist on 4 ply, never 3 ply.
Greg
Using 1/2" OSB on framing that's 24" O.C. is the norm around here. I've never seen a roof that had problems with the plywood sagging between the framing. The only exception would be where the roof leaked for a long time and the plywood got wet. .My previous employer had done their first building with trusses 32" O.C. with 3/8" plywood. I was amazed that it held up like it did. It was terrible to walk on, but didn't look too bad. Although it did start sagging after about 15 years or so.
If you were going to shoot a mime, would you use a silencer?
Jay...down here they almost exclusively use OSB (the thin stuff) for roof decking. Some use the rough cut boards and in my opinion, at least compared to the thin OSB, the boards are a better choice. On new houses down here you can actually see the sag after the shingles are installed on a brand new roof. I'd use plywood myself or go with the boards, either seems to be a better choice versus the thin OSB. Granted, we don't have stuff like snow load to worry about down here like the northeast, but I still don't like to see the sags between the rafters on new construction, especially in light of what they're charging for new homes in this area. When the sun hits the roofs just right here, you get reminded of hills and valleys....not my kind of desire in a new home.....If you aren't one of the one's I'm talking about,you shouldn't have any complaints....
Jay..just for additional thought...I never saw a house built in either Gouverneur or Watertown with OSB on the roofs...think the first time I ever saw OSB used in any capacity for building was when Ft Drum expanded back in 85 and they built all those housing units in a matter of months, and they had problems galore with those places after just a few months...I remember a few years ago they were actually at the point of rendering some of them unliveable due to poor construction....imagine where they'll be in just a few more years, and I do understand the new housing project the Drum has ongoing now has far more stringent codes for building.....this time it may not be "make a quick buck and leave " work....If you aren't one of the one's I'm talking about,you shouldn't have any complaints....
jay... this hack has always used 1/2" ply ( with clips ) when the framing is 16" oc
and 5/8 ( with clips ) when we frame at 24"Mike Smith Rhode Island : Design / Build / Repair / Restore
Hey- 20 years ago when we did Ryland homes up in Maryland, we were putting 3/8 on trusses 2' o.c..
A typical roofers first day on the job carrying a bundle of shingles would crash through the sheathing iffn he stepped in the middle a two trusses.
I don't think you will ever notice the diff at 16" OC in Connecticutt
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Taunton University of Knowledge FHB Campus at Breaktime.
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Another 'hack' here, 1/2" OSB or 5/8 osb if slate.
But I don't choose the lumber.
I didn't do it....the buck does NOT stop here.
Which is basically what I said, before being called a hack.
Guess I'm a hack too Gene. Although I will say I try to take many factors into consideration and build the best I can. I have installed 1/2" though plenty of times as both a sub and as a contractor. I see 1/2" more than 5/8" and I've been in several states. Just to clarify though, I've also seen the sagging roofs, which is kinda related but a whole nother topic.
I guess that all the sagging I have seen was on 24" OC.This thread is turning into a hacky-sack;)
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We have a 2500 sq ft hip roof. 5/12 pitch. 7 years of age.
7/16" osb, 24" truss centers,
We have an area snow load of 85 lbs. (ground snow load)
We have had as much as 3'-4 ' of wet snow (heavy) on this roof for several weeks at a time over every winter.
NO PROBLEM.
In other words, you are OK
Did you use H-Clips?Joe Carola
I took a little drive around the area today and scoped out some jobs in progress, and also to tally those I observed being framed up this past fall. I was looking at what was getting used for roof sheathing.
I was shocked! I thought at first, pulling out of the drive, that I was certainly a hack, having used OSB with clips for roof deck. But to my astonishment, I found I am living in a sea of hacks!
Keeping count, I hadn't even left my own street before encountering other jobs being erected by hacks like me! A monster of about 7,700 sf, going up four lots down the road, they're hoisting the foul stuff up on the truses today!
Five more lots away, another hack job! A weekend house for a plumbing contractor from down near the big city, this one was a panelized and trussframed job. Hack city! OSB on the deck, it is up now, but I saw it go on last October.
Around the corner, and across the road where I completed a spec house (hack, hack, of course), a little palace is being specced with a 12:12 roof, nice little cross gable stickframe arrangement, but (gasp!) it's being done by another hack, with the dreaded OSB up top!
Over to the John Brown Farm meadow, where a couple guys I know are throwing up megaspecs, both in the Adirondack great camp style, each on multilist for well over a mil. Whaddya think is up on the trusses and rafters? Call these guys fellow hacks, because the product, vile as it is, begins with the cryptic word "oriented."
O what shall we do?
Bouncing out the peninsula road, along the lake shore, where the lots are going for maybe $2.5 mil and up, and the new boathouses are going for a mil apiece, it's another hack attack. I meet with my excavator, who is knocking down an old camp and boathouse so the new owners can build wall to wall, and what do I see, on the two lots adjacent? A hack to the left, another to the right. Megacamps, roof planes everywhere, octagonal turreted porches, you name it, all OSB.
Wondering how much of this is driven by pricing, or technology, or whatever, I stop in at a lumberyard I deal with, and take today's price quote for 5/8 roofing panels.
OSB is $22.00, CDX is $19.25. What???? If the supposedly better stuff is cheaper, then why are us hacks all using OSB?
I pull into the McDonald's and go in for a bite, and run into one of the guys I saw earlier, out on his site. We discuss it, and it seems that the ply coming out of the mills and into our local sources for the last few years, is just not flat and uniform, like the OSB is. Turns out to be a bitch to work with up on the rafters or trusses, trying to get it to pop into the clips.
And another thing. And this is from all us hacks. If plywood is so wonderful, and OSB so bad, why are we all convinced that Advantech is the only subfloor sheathing to use?
Gene, the issue of the discussion wasnot osb vs plywood so much as 1/2" sheathing vs 5/8" sheathing
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Sorry. I got distracted by the thread hijacker that cannot stop from throwing flames. Got off on that "hack" tangent. It was sort of fun, though.
You're right. It is a simple member sizing structural question, this thread.
What's my live load? Dead loading? Exposure condition? Importance factor? Material properties? Deflection criteria?
There was a lot to assume, but when the thread initiator said "Connecticut" and "16 inch spacing," I took a wild azzed guess and said he was OK with 7/16".
Me too. I could tell of course, that you were having fun discoursing about your run down the concourse on the way to the golf course
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I hate starting a discussion that I never respond to!
I am just now getting back on to see all of the responses. I did look back at the plans, and there was a section that did spec 5/8" plywood instead of 1/2". I pushed for the 5/8". My builder had already used 1/2" on a very small section, and I decided in all fairness to let him keep that section. He has started sheathing now with 5/8" and I must say, all of the foor edges are much straighter and smoother. In the long run, I am glad I pushed for 5/8". Its going to be a lifetime house for us, I hope. Someday soon I will post pictures of the construction.
Thanks all.
"I did look back at the plans, and there was a section that did spec 5/8" plywood instead of 1/2". I pushed for the 5/8".Since your plans called for 5/8" and he started installing 1/2", what's his reason for putting on 1/2? If he did the whole roof in 1/2" and the plans called for 5/8" he would've had a problem during inspection time.Why would you be glad that you pushed for 5/8", you should've been getting it anyway so there's no reason why you should've had to push for it. Did he give you a hard time about it?Joe Carola
That was the first question that popped into my mind when I read that your specs called for 5/8. There should be no problem here as to the solution. Either it was an oversight on the builders part, (which very well may be since you say he is overbuilding), or he's trying to slip one by to save a little $$. But as you say, it's done now and you're happy.
No, he didn't give me a hard time - especially when he saw it on the plans. So far to this point (most of the framing), our relationship has not been contentious. But I do want to be fair, since at some point in the future, something will come up that was not detailed out in the plans, and I'll need his commitment to be fair to us as well. We'll see. So far he has been great.
I'm surprised that no one except Hube raised the point of slope in this discussion. As far as I'm concerned, it's one of the three major determining factors.
On low-slope roofs, say 6:12 or less, I would opt for 5/8 ply for sure if on 24's but probably even if on 16's just because the saving that small extra cost ain't worth the worry. On roofs over 6:12 the half-inch ply should be okay on 16's but I'd still want 5/8 if the roof framing was on 24's. I have seen too many scalloped roofs due to undersized sheathing.
I do not use osb on houses or garages; only on outbuildings. In fact, for small roofs on sheds and suchlike, I prefer to use 1x6, even though no one around here mills t&g 1x spruce anymore.
The few times I have worked as a framing and roofing sub for another builder, I have found that it is very common to use the cheapest material code will allow. The NBCC allows roof deck material I personally think is insufficient for long-term durability. This surprises me, but until they make a rule preventing me from building better than code, it ain't gonna ruin my sleep or make me change my ways....
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
You feel better now Gene?I never said OSB wasn't good on a roof. I said I've never seen OSB on roof or I've never used it. I said that someone said that there was a house with 1/2" on a roof with 24" o.c. with no H-Clips and I think that was a HACK JOB.Joe Carola
You ought to get that cough looked at. Hacking like that could be a sighn of pneumonia.
Here in the south, 15/32" OSB on rafters at 24" is pretty much the norm for most houses. However, on almost all those houses the locations of the rafters are evident from the outside. Additionally, even though all the OSB I have seen around here has stamps all over it requiring 1/8" separation between the sheets, all the sheets are jammed up to one another. So, you can also see every sheet of OSB from the outside. And that's with the final shingles in place.
While some of these features may be permissible by code, the resultant deformed roof deck leads to premature death of the shingles.
Overbuilding the framing is not necessarily a good thing. If you are talking about 12" stud spacing when 16" is sufficient, the insulating value of the wall, regardless of the insulation in the cavity, is diminished because of the increase amount of bridging from the exterior surface to the interior. Also affected is the increased costs of installation of other elements, such as insulation and drywall.
This horse has definitely been beaten to a multitude of deaths. Anyone out there using 5/8 advantech t and g? I prefer it to the clips.
Dustin
That's the way I've gone - with huiber advantech. The osb telegraphs so I have never used it on any spacing.
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Here in WNY, 7/16 OSB is the norm for residential construction, 5//8 CDX for commercial. Ii believe that the larger scale architects that handle the commercial jobs understand the difference. Not toi say that 7/16 osb w/ clips on 16 centers is bad when it is spaced properly but it never is. I agree with the remark about 5/8 being difficult to set in the clips because once the load is unbanded, the sheets spring to life. And as far as hackfest goes, we're all prostitutes of the almighty dollar and if the builder wants his name on it, then that's what he gets.
Most of the houses I do are spec'd for 5/8 ply on the roof. Part of the issue here on the Oregon coast is wind and seismic. I mostly stick frame on 16" centers (because I like to), but, even with clips, 7/16 OSB or 1/2" ply on 24" trusses feels spongy to me.
But, having spent a lot of years in the solid wood products manufacturing sector, I tend to believe a lot of the reason a thicker sheathing is used out here is the gradual transition from old growth doug fir timber to 2nd and 3rd growth wood with an inherently softer and weaker wood structure.
Some of you have mentioned using 4 ply CDX....I don't see that out here anymore....it's all 5 ply, whether it be 1/2" or 5/8". The 4 ply that was being peddled out here a few years back would make anybody take a hard look at OSB.
Now, I'm not going to try to start a fight, but last year I built one of those log kit homes for a customer. The kit came from Pennsylvania, the ply sheathing from the Carolinas and the framing lumber (floor joists, ceiling beams and rafter stock) came from some mill in Maine and another mill in Eastern Canada. The "finish" trim and finish wall planking were kiln dried white pine stock from Pennsylvania.
The ply wasn't bad compared to the lumber, but if it had been locally purchased, I would have sent it back, because of a lot of delamination and beyond-grade surface defect, along with major inner core voids.
The surfaced pine 2 X 10's for the subfloor varied up to 1/2" in the wide dimension and had to be hit with an electric plane to correct that and the extreme crown in over half the pieces. Overall, the lumber was about what I'd expect to find in bargain alley in a big box. Fortunately, they sent enough overage that we were able to scrounge enough decent stuff to finish the job....but what a waste of time!
Alot of the discussion here and what's presented in the magazine provide a lot of contrast with regional differences.
I tend to think this discussion sheds light on one of them.
Advantek is difficult to find here, so I have no experience with it but plywood, despite being a commodity, varies a great deal in quality from mill to mill.
I know the mills locally that put out a good product so, when I'm buying on a unit basis, I spec those mills specifically (hard to do that with broken unit purchases).
But, having participated and/or lurked here for a long time, I tend to think a lot of my experience with that log home kit is what a lot of you "East-of the-Mississippi" folks have to contend with on a regular basis, when it comes to basic framing material.
Don't get me wrong, you have a lot of advantages in the materials world, like more inexpensive granite, marble, soapstone, etc.
Sometimes, it has nothing to do with being a hack....it's just a matter of playing with the hand your dealt. Or spending some extra doe and doing special orders. (Like, maybe I need to call in some Advantek....:-) ).
Given that I'm in Florida and that at least one proposed code, well backed by theoretical research and observations after hurricanes, recommends 5/8" for both roof decking and sheathing I would push for it on any home I was having built.