Thanks for the reply yesterday on spans. And for today, when rafter ties (CEILING JOISTS) have to be lapped by each other over a beam in the center of a span.. What is the rule (if there is one) on the ammount to over lap them? Or is it permissable to sandwich them butted between two other similar pieces of some length?? Again over a beam. And maybe blocking run between them the length of the beam over the beam? Thanks russ
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Replies
here, I'll bump this up for you since it's fallen off the board - -
I'm far from the most experienced framer (or engineer) here, but I'll not let that get in the way of offering an opinion...
I'd lap them two feet - or there 'bout - - rack 'em and let them fall where they do - - if you want to sandwich them so the rack falls correct for DW nailing, it'll be a bit more work, but maybe you'll make it up on the sheetrocking...
Keep in mind that there's no need to make the center joint any more secure than the connections at each end (assuming the center rests on a wall).
I frame in New Jersey and we never let them over lap more then 1' because after that there's a chance that they can stick down past the bottom of the other ceiling beam and cause problems for the sheetrock.
Joe Carola
Edited 6/17/2004 7:55 am ET by Framer
I've heard that a long lap can cause problems when the joists are loaded heavily. If your joist are cut 2' long and the deflection is significant, the lap joint will be stressed as the overhang wants to pull up against the lapped joist.
Never seen this actually occur, but I can see how it could be a problem.
Jon Blakemore