Roof sheathing options

[RayN]

I posted early on sheathing a 12 over 12 roof.  Last weekend I finished my rafters and I tried one 4x8 sheet of 7/16" osb by passing it thru the rafters.  Well it is doable but certainly awkward.  

So I started thinking about options on making this a little easier,  I realize the sheathing serves two purposes - a place to nail the roofing to, and to stiffen the structure:  Would any of these ideas be just as good a nicely laid 4x8 sheets:

1) Ripping the 4x8 sheets into two 2x8s,  lose something on the stiffness factor.  Easier to handle, would the 7/16 osb be to thin?  Should I go for the next thickness up (more $).

2) Rip them in half the other way,  have 4x4 sections.  Use a 4x6 section to stagger the joints. on every other row.

2) Getting 1x8's or 1x12's for the local saw mill and using those - the old school way.  I rough figured from an old pricelist,  and since waste would be less it figures out to be a similar price for 8 footers as the osb.

[RAB]

A few thoughts –
Like most of us that all-terrain forklift with a man basket is never available when you need it. I have unfortunately had this situation happen a few times and came up with a few ideas.
-Before setting first course put a 16d nail in the center of the facia at 2' and 6' to prevent the sheet from sliding off the edge. If you use 3 nails the sheet has a tendency to rock on the center nail -
- Before the next course is installed install toe-kicks 12" down from edge (commom mistake is to put too close to top edge), use the type that roofers use rather than a 2x4 cleat style as they will give your foot something to stand on.
- If your facia edge is closer than 12' from the ground, sometimes using the "work pickup truck as an intermediate stage for boosting the first course.
- If you have only 2 people build temp platform on roof, boost to platform - then lay sheets.
- Use nails at stops for sheets after the first course
- Even most experienced will say 12/12 is not a easy or fast job
- Labor/time is a wash when using smaller sheets

An interesting note is that once you start to fall on a 12/12 only the ground will stop you. OSHA requires harness and rope for most slopes over 6/12 regardless of toe kicks and eve height. You can often be more productive with this safety system.

[peg_688]

Posts: 146
  Re: Sheathing 12/12 roof tips NE1?
« Reply #5 on: Oct 6th, 2005, 9:35pm »  Quote  Modify  Remove  

--------------------------------------------------------------------------------
 Rent these at your local rent it center.
 
  
 
   Qual-Craft 2500Q Roofing Bracket Adjustable to 10° Pitch - 10" Platform
  
 
   Pretty poor picture , sort of shows the jack upside down.    
 
  Nail your first row of sheeting on either from a ladder or the stick it out from inside method.
 
  Once the first row is in place you nail thru the sheeting into a rafter thru the holes in the jack. Once they are in place a 2x6 rests on the jack and you have a safe way to sheet your roof .  
 
  Once to the top pull jacks and bang the nails in, use the slotted holes and you can bang up on the bottom of the jack to release it ,  nails roll out your felt , 1st layer, shingle over it then , use the roof jacks slid under the bottom of the shingles.  Again that is ladder work , or you could build a site built staging to work off , or check with your rental center they may have pump jacks or wall brackets availble to rent.
 
If your using metal roofing the roof jacks won't help much , or at all.  
 
  Good luck, how ever you do    
 
 
  IP Logged

--------------------------------------------------------------------------------
When in doubt , build it stout with something you know about .  

[peg_688]

 Opps dbl post

[RayN]

Yes thanks for the tips on the process, and safety.  

 I was wondering more if changing the material (4x8 sheets of 7/16 osb) by cutting them in half would be o.k. from a structural standpoint.  I realize it would take more time,  but it would be easier, thus safer, to handle.   Also what are the groups feeling son using 1x material instead of osb?

[Bart_Cubbins]

It may depend on what kind of roofing you plan. Metal roofing can go over skip sheathing or purlins. I'd be a bit more concerned with asphalt shingles though, even though that's how they used to do it. It just seems to me that the boards are likely to cup and curl in the sun, and the resulting raised edges might cause the shingles to wear out faster. That's just a thought, don't have any experience to back it up.

The half sheets of OSB would probably be plenty adequate. Especially with the 4x4 pieces, you wouldn't be losing much if any shear strength. If you're putting on a metal roof, the roof panels also contribute a lot of shear strength.

[peg_688]

Ray    

  You might be in a little deep but lets work on it ok?  I'm not bustin ya ok .  

  The real problem is the steep pitch anyway you cut it ya got to get on the roof , even if you use boards your going to have to be able to stay on the roof and you , or someone is going to have to roof it .  The roof jacks will let who ever do that .

  That being said and I hope you take all this   the  right way.   Really  

  The boards will work , yes they could cup if left to the weather for a long period( but if the OSB is left uncovered for the same time period it will be useless/ ruined ). The house I live in was built in 1947, I've re roofed it , and resided it and will tell you there is not one sheet of plywood on the orginal sub floor , side walls or roof . All 3/4 " shiplap boards pretty rough boards at that , lots of knots , etc .   She's one solid old house

  Ripping the sheet in 1/2 creates more work , more plywood clips , etc but still in all, ya it will work.

 IMHO the boards would be better than OSB on the roof . I personal don't like OSB on  roofs , I'd rather have 5/8 CDX , do I always get my way,, no hardly ever, as price drives most jobs and OSB is cheaper , is it better , IMHO no .

  But back to the bigger issue ,the  12in12 . I really wish you good luck and do not mean to sound over bearing .  

  Of course all the above  is moot if there is any specal engineering or disign features to your cabin .

   Good luck Ray   PEG

[glenn-k]

All my roof boards are 3/4 solid wood shiplap or straight boards but I have my own sawmill and don't like the smell of OSB.  I have very little roof that is over 2 1/2- 12 of course most of my roofing is dirt so not much applies here.

I have to admit that I like the 4x8 sheets of plywood like PEG if doing conventional roof and I have my choice.