I don’t know if this is covered by any building code, I can’t find it in mine (Ontario).
What size framing do you use for spans that carry no load OTHER THAN DRYWALL?
For instance: finishing a basement, drywalling around a mass of ductwork. Say you have to span 6 feet across & under the ducts. What do you use?
What about 10 feet? 12 feet?
And what if you are attaching 2 layers of 5/8″ drywall?
There is no live load on these “joists”, and the only dead load is the (possibly multiple layers of) drywall.
Thanks,
Tim Ruttan
Replies
can you say "suspended tile ceiling" ? :)
Geoff
Not following you competely... would the wall be from the floor and terminate below the ducts or will the wall be open below?
Assuming that you want this to be a header over an opening, you could virtually get away with simple 2x4 studs and the DW glued and screwed to the structure, effectively building a tortion box of sorts. Should be strong enough to support itself.
(caveat: I'm no engioneer and don't know all your particulars and if my idea kills or maims you, you're on your own)
anyhow, you can also build a header out of 2x6 which is pretty inexpensive anyhow... with a plywood flitch plate between the 2x's, you'd have no probs for certain. (still refer to caveat above)
When you're this good, EVERYONE wants a crack at you!
http://www.petedraganic.com/
Edited 2/24/2007 9:12 pm ET by PeteDraganic
Depending on the sizes, you might just make it easy on yourself and just use 2x12 as the down piece, with a piece of plywood or OSB as the bottom floor/webbing between the two enclosing walls. You will have no problems finding wood to nail to, and your assembly is greatly simplified.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I think I know what you are talking about. I've done the same thing in basements to clear ductwork and pipes etc by lowering the whole ceiling instead of building soffits. Effectively it is a "drop" ceiling of sorts since you are attaching the drywall to a new set of ceiling joists instead of using the bottom of the floor joists. Same thing if you were framing a ceiling w/ an attic above it.
Anyways the IRC has span tables for ceiling joists w/ no live load. I don't know about Ontario but I'm sure it's in there somewhere.
Soffet rule of View Image : 2' of span for each inch of joist depth. <=8' = 2x4 joist.
Cross blocking if over 2/3 maximum span. >6' span with 2x4 = block.
With double 5/8" DW, block at 1/2 max span. >4' span with 2x4 = block.
In any case, blocking not greater than 8' OC.
Like Pete said "(caveat: I'm no engioneer and don't know all your particulars and if my idea kills or maims you, you're on your own)"
SamT
Anyone who doesn't take truth seriously in small matters cannot be trusted in large ones either. [Einstein] Tks, BossHogg.