ceilings to strap or not to strap
Whether to do or not with boarding finish is dependent on which direction you want the boards to run. Boards perpendicular to the trusses will go right on the bottom chord of the truss and will do the same job the strapping does, structurally, but if you want it to run parralel with the trusses, you need strapping to nail to.
drywall for ceilings at 24"oc needs to be at least 5/8" thick to avoid sagging over time but 1/2" spans the 16"oc fine.
Some places would require the SR by code before covering with board so check your jurisdiction.
Don't forget the vapour barrier.
Thanks again for the help. Could you tell me what you mean by some places require the SR by code before strapping? What kind of moisture barrier would you use? I think I have seen sheets of plastic used, but couldn't that cause condensation?
I have another question as well. I used 2x4 lookouts laid flat over the gable truss and nailed into the side of the 2nd to last truss. I put them on 24-inch centers with a total overhang of 24 inches. I also added a 2x4 on its side nailed to the side of the overhanging part of the lookouts. So the overhanging part of the lookout is 2 2x4 shaped like an "L". I also put hurricane straps where the lookouts attach to the gable truss.
I asked a local contractor if he thought that was sufficient stability for a 2-foot overhang and he said yes. But I have a framing book that I noticed said I should have used 2x6s for my lookouts (I always seem to notice these things after the fact). I think the book was referring to high wind areas though and I don’t think Georgia is a high wind area. Do you think I should go back and add another look out so that they will be on 12-inch centers to satisfy the inspector? Should I add a 2x6 instead of a 2x4 lookout?
I didn't say to put SR before strapping - but after strapping and before beaded board. Just check with local inspector before you do it. Personally, I think it un-necessary.
condensation occurs when warm moist air reaches a cold surface. If you place plastic or use faced fibreglas insulation behind the ceiling of your choice, it stops room moisture from reaching the cooler, unheateed attic space above, where it will then condense and appear as tho you had a roof leak. cathedral ceilings are more renowned for this because they are harder to ventilate, making the vapo-bar more important.
I hate to keep asking so many questions. I should have been more specific when I was asking you about "SR". What I ment was what does "SR" mean? Is it an abreviation for something? Sure would like to know what it is. I dont want to leave anything impostant out of the ceiling.
Thanks so much