Replies

1. 
   Guest_ | Sep 14, 1999 02:58pm | #1

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   Sun,
   A little bit more about your roof: How steep is it? Truss or stick frame? Where are you located? I dont use osb on roofs around here. It doesnt have the nail holding power that plywood does. Also I dont use less than 5/8 plywood. Boy do I hear about that every time I build one.
   Rick Tuk

1. 
   Guest_ | Sep 14, 1999 03:22pm | #2

   *Sun, I have to agree with Rick and Fred sounds like 1/2" OSB on 2' centers. Even with clips it will wave.Vince

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   Guest_ | Sep 14, 1999 05:40pm | #3

   *Sun,Give us a little more info. If it's the OSB, you should be able to see the outlines of the 4x8 sheets. This doesn't sound like "wavey" to me. The basketball sized dip sounds like a sheet didn't hit a rafter on the end or corner. You need to talk to your builder, roofer, and shingle supplier, right away. Nobody likes to go back for warranty work, so keep pushing!(Especially the builder, it's his responsibility)John

1. 
   Guest_ | Sep 14, 1999 10:57pm | #4

   *This one could be hard to figure out without having seen it to determine exactly what the customer is calling wavy.At first guess I would say MAYBE decking isn't nailed down, or clips are missing.I still have yet to find a 7/16 osb roof with clips that was wavy.I find tons of wavy PLYWOOD roofs.Also, with laminated shingles........If the lamination lines up on several succesive courses a "wavy" area may appear even though all shingles are laying flat.good luck,Stephen

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   Guest_ | Sep 19, 1999 03:32pm | #5

   *Get to it right away. DON"T wait Run don't walk you paid for it Keep after the builder, You have one year, After you sign the papers. Your ROOF has a lot under it your(Family). I Don't trust osb anyway..No Matter how thick.Listen to Rick tuk.. Could be anything but have it fixed NOW. Roofs cost alot. And a true roofer knows what he's doing. Keep after the builder. Can't tell you what this means. Think of it as money. Sometime plywood gets wavy, But osb... On 2' center no way. Water and osb don't get along.Ask any ROOFER

2. 
   G.LaLonde | Sep 19, 1999 04:00pm | #6

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   It's been my experience that most wavy roofs are caused by sloppy framing techniques and have nothing whatsoever to do with the sheeting on the roof. All you have to do is set roof trusses slightly out of center and you will create a very visible wave in your roof. The same is true with conventional roof framing because of differing dimensions in the lumber and poor attention to crown placement when framing. I would suspect that your framer was a hack artist! OSB or any other sheeting should be covered immediately upon placement. I find that it lays much flatter than the plywood available to us and is certainly strong enough to use as roof sheeting. If your whole roof appears this way, I'm afraid there's not much to do about it.

1. 
   robbwilson | Sep 25, 1999 10:02am | #7

   *One other possibility is that insulation was laid in the rafter bays, perhaps foil backed, or there is not sufficient ventilation going on, and the OSB is buckling from heat. I've heard of these types of heat problems delaminating plywood within one year.

3. 
   Guest_ | Sep 25, 1999 05:29pm | #8

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   Tar paper is another possible cause of the wave, if it was'nt covered right away.

   Brian

4. 
   Frank_LaPiana | Sep 27, 1999 07:39am | #9

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   Ok, I'm not a roofer by any means, and don't know a hell of a lot about it.

   BUT... I've been doing some reading up on roofing, OSB, and plywood. From what I've read, OSB is "not recommended for roof sheating under any circumstances." That was from some "independent research" sponsered and published by an OSB group. Although OSB is superior to plywood in some respects (actual strength, deflection, etc), when exposed to water or moisture it will swell.

5. 
   Sun_Shadow | Sep 27, 1999 02:57pm | #10

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   We have an OSB roof with 40-year composite shingles. It's a new house, which was roofed less that 6 months ago. At first we didn't observe this, but the roof is slightly wavy in some areas. Tonight, we saw a basketball-sized dip over the eave that is pretty deep. That set off the alarm bells! We wondered if the slight waviness is also something to be concerned about.

6. 
   Guest_ | Sep 27, 1999 02:57pm | #11

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   Mr. La Paiana Frank, This is what i said, And they who ever they are , Deleted my notes about it As I said no true roofer would use OSB And they deleted it after one day.....