Replies

1. 
   john7g | Oct 19, 2007 06:35pm | #1

   1/2" is pretty common for roof decking.  It'll say in the stamepd data on the sheet what it's rated for.

2. 
   CapnMac | Oct 19, 2007 06:37pm | #2

   First off, welcome to BT.

   (<hint>second, fill in your Profile<hint>)

   As far as I know (AFAIK), sheathing thickness is not specified by pitch.  Here lately, the trouble is to get roofers to use any specified thickness material at all (which is not at all helped by the ridiculous range of thicknesses available either).

   If you can find 1/2" CDX that matches what is there (and is not 11/16 or 21/32 or 16mm), then, it's probably ok.  CAVEAT:  That presumes the rest of the structural elements of the roof are good; 2x4 rafters at 24" centers in snow country not being even close, for example.

   Tell us more of the project, who it is for, who is running it, where is it in the planning/execution process, etc.

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   JGvZ | Oct 19, 2007 07:36pm | #3

   I've started the project already. I'm doing it for my brother. It started out as just re-roofing, but turned into more due to some rot under a flat section. I've replaced a wall and reworked things to eliminate the flat part. I already ordered and had delivered 1/2 cdx for the roof, but started questioning whether I should have gotten 5/8 or 3/4 instead. All the framing is adequate, 16" on center, etc. I'm near philly so there is some snow load, but rarely a lot.

1. 
   Framer | Oct 19, 2007 07:55pm | #4

   It also depends on what's code where you are. The new code might require 5/8". You're doing the roof over. If you need inspections, then you have to ask what is code. If you're not going to get permits and inspections and get caught and you're required to use 5/8", your in trouble.Joe Carola

1. 
   streets | Oct 19, 2007 09:23pm | #5

   The thickness of the roof sheathing depends on the spacing of the rafters, the weight of the roofing material and the wind conditions (nail withdrawal). I always use 5/8" @ 16" o.c. but 1/2" can work in normal conditions.

1. 
   Framer | Oct 19, 2007 09:54pm | #6

   The thickness of the roof sheathing depends on the spacing of the rafters, the weight of the roofing material and the wind conditions (nail withdrawal). I always use 5/8" @ 16" o.c. but 1/2" can work in normal conditions.

   Never heard that before around here. It depends on what's code and what's on the stamped plans. When I first started framing in 1983, all roof sheathing was 1/2" . Around 1987-88 it changed to 5/8" regardless of what the centers are. All stick framed rafters are 16" centers here.

   I only stick framed one job 24" centers and the sheathing was specked at 5/8". So around my area it's 5/8". Yours might be different. The only time we use 3/4" for the roof is on flat roofs.

   Joe Carola

   Edited 10/19/2007 3:53 pm ET by Framer

2. 
   streets | Oct 19, 2007 11:42pm | #7

   Joe, on my jobs, I draw the plans.Building codes are minimum standard and they seem to be unusually optimistic about roof sheathing. I have to decide what I think is best by taking into consideration the issues I think are important which is what I mentioned in my earlier comment.

3. 
   Piffin | Oct 20, 2007 05:26am | #9

   "Never heard that before around here. It depends on what's code and what's on the stamped plans."In most places, the code is less about specifying sizes and more about end results.They spec that the roof must handle a XX# live oad and smaple soime ways to do that, you if you can show that you meet the end requirements with 2x2 framing at 6"OC with 3/8" sheathing, that is whaat they need to know.So whether or not 1/2" sheathing works can indeed depend on whether the framing is 16" or 24" OC. With 1-1/2" T&G sheathing, the framing might be located 38.42" OC if it is sized to meet the laod requiremens 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

4. 
   Framer | Oct 20, 2007 05:41am | #10

   If you just use 5/8" all the time, you'll never have to worry about any snow loads around here. I've never seen anything specked above 5/8" before.

   Sheathing is never an issue or conversation as far as what to use. I have seen some plans call for 1/2'when I think about it, but I always use 5/8" and the builders agree. Never had an inspector question it before. That's one thing that I have gone against that on the plans.

    

    

    Joe Carola

5. 
   Matt | Oct 20, 2007 02:37pm | #12

   >>   I have seen some plans call for 1/2'when I think about it, but I always use 5/8" and the builders agree. Never had an inspector question it before. That's one thing that I have gone against that on the plans.<<

   Do you do your framing turn key (with you supplying the material)?

6. 
   Framer | Oct 20, 2007 03:13pm | #13

   Matt,Some jobs I supply framing material, windows, doors and labor, and some jobs just labor.Joe Carola

2. 
   Piffin | Oct 20, 2007 05:17am | #8

   Small snow load and 16"oc you are fine 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   JGvZ | Oct 20, 2007 07:11am | #11

   All your input has been helpful, thanks.I think I'm going to stick with the 1/2" I already have, and do it with a little more confidence.

1. 
   Doobz26 | Oct 20, 2007 04:31pm | #14

   Find out if you need to use H-clips between the sheets if you are using 1/2".  Around here 1/2" is ok but H-clips are needed.  If 5/8" is used no H-clips are needed.   We design for 70 lb. ground snow load... and usually trusses 24" o.c.  

2. 
   Stilletto | Oct 20, 2007 06:15pm | #15

   I thought about that too,  we use 1/2" alot here in southern MI. 

   Then he said 16" OC rafters so in that case we would bypass the clips. 

   But it's all in their codes and snowloads,  clips wouldn't hurt anything even with 16" OC.  And they are fairly cheap. 

   Matt