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View Full Version : Need some advice on roof framing.


Tom Rick
05-12-2010, 8:04 PM
I have to admit to forgetting much of what I used to do all day long when I was framing houses..

Question for you guys:

Do I have to place a trussed roof on 16" centers?
I am putting up a small shop of 20'x25' 6/12 roof with the trusses running across the short way.
Can I put the roof trusses on 24" centers if I am going with 5/8" sheathing?

Thanks all
Jaromir Svoboda
05-12-2010, 10:04 PM
Yes,here in Illinois you can.7/16 OSB is fine.
Von Bickley
05-12-2010, 10:10 PM
In SC, trusses are installed 24"oc. Some people go with 1/2" sheathing but 5/8" sheathing makes a much better roof.
Alan Trout
05-12-2010, 11:05 PM
You can install trusses 24" OC in most locations if they are engineered for that spacing. I agree I would recommend at least 5/8" plywood.

Alan
Chris Damm
05-13-2010, 7:47 AM
Your truss spacing depends on what spacing they were designed for. Most trusses are designed for 24" OC. Most places allow 7/16 sheeting if you use "H" clips on the sheeting. I prefer to use 1/2" sheeting.
Why is the building 25' long? 24' or 26' makes better use of standard building materials.
Brian Effinger
05-13-2010, 10:03 AM
24" o.c. is fine (if the trusses are designed for it - ask your supplier), but I wouldn't use anything less than 5/8" sheathing. While 1/2 ply, or 7/16 osb would work, you will see the line of each truss telegraph though the roof.
Tom Rick
05-13-2010, 7:15 PM
Thanks guys- 24 on c it is with 5/8" CDX ply sheathing.

Anyone using the scissor trusses?

The building is just 25 feet long but I am thinking of using attic trusses for the first 10' to give me some lumber storage over the benches and then scissor trusses for the rest of the run to give material handling headroom over the saws.

Thanks again
David Helm
05-14-2010, 4:39 PM
Sounds like you've got it under control. 24 inch spacing is standard almost everywhere. If you want to have storage you should get trusses design to carry a load on the bottom chord (most are not) or use rafters and ceiling joists instead. Scissors trusses are a nice way to get a vaulted effect and still have insulation and structural soundness without having to resort to a structural ridge.