Expert: Bruce E. Johnson - 8/11/2009

Question
Bruce, thanks so much for your help. It wouldn't let me ask another follow-up, so had to ask a new question regarding the open rafters on my sunroom's "shed" roof.  I don't want to be a nuciance, but I have 3 more questions and then I think I'm good.

1) I'm going to put the collar ties onto the rafters so I have a flat section on the ceiling. The roof is only a 4:12 pitch. and I'm wondering how long the collar ties should extend against the rafters. Please see this pic:

http://i629.photobucket.com/albums/uu14/mpildis/collartie.jpg

I was thinking about making them 48" long so I get 2 of them out of an 8' 2x4. That would give me a 16" against the rafter from the first point of intersection. If I make them 52" long, they would stop right where they hit the roof plywood. Making them longer than that and having to cut the roof angle on them would be a real pain and seems excessively long to me. Does 3 10D nails staggered per collar ties sound sufficient?

2) Should I place little studs between each rafter at the half-way point to keep them from twisting since it's going to be an open rafter ceiling?

3) The rafters are toenailed into the top plate and have simpson h2 hurricane ties on the outside wall. Since it is going to be an open rafter ceiling, should I place hurricane ties on the inside wall as well or is this overkill?


That should be it.

Thanks!

-Mike


Answer
Hi again Mike, if your nails can be at least 2" from the end of the rafter your collar length will work.  Two inches will help keep the end of the board from splittling too much.  3 #10's should suffice.  Yes you should use some little studs between the joists..this is called "bridging" and should be installed for every 8 feet of span or mid apsn on anything 16' or less.  I like make my bridging out of the same material as the the rafter to provide solid blocking.  One set of H clips should be fine..I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com