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How to attach these rafters

chrisr710's picture

Hello All,

I am installing an addition onto my house, it's about 40 ft long by 12 feet wide. I believe the roof style is called a "patio roof", where the (3) 2 x 10 ledgers you see are attached on the existing roof, and the new 2x10 rafters attach to them. Although you can't see it in the photo, I also will be supporting the new rafters right from the top plate of the existing house wall, so they will be supported in 3 places (the ledgers, the existinig house wall, and the new exterior wall). I was going to put blocking between the rafters as well.

My question is how to fasten the rafters to the ledgers. Obviously toenails from either side is the easiest, I guess... my thought was to place two of the brackets shown in the photo, maybe one on either side... one on the middle ledger 2x10 and one on the lower, and fasten those with 1/4" 1 1/2" lag screws? The part number of that bracket is ML26, and then put a few toneils on the part where there is no bracket.

I do have a permit, and plans, which were approved but the fasteners just have to be up to the international building code. I was wondering how some folks with experience in this would make those attachments, in order to do a good job and satisfy the building inspector.

THanks!

I'd be more concerned about (post #214820, reply #1 of 7)

I'd be more concerned about the other end.  Wind uplift is a significant hazard on such a roof.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Get a simpson strong tie (post #214820, reply #2 of 7)

Get a simpson strong tie catalog. There are a number of rafter tie systems, depending on what your uplift requirements are there,

Greg

Hi there,     The tops of (post #214820, reply #3 of 7)

Hi there,

    The tops of the new rafters don't require hardware. Two 16d toenails from both sides into each of the 2x12 nailers would meet code.  So 12 nails per rafter top cut.  Where the heel of the rafter lands on the new top plate you need toenails and a hurricane tie, a metal strap with a 90 degree twist in it.  These are supposed to be installed on the exterior of the frame before the sheathing, but 99 times out of 100 they are installed on the inside of the wall out of convenience.  Structural screws driven from inside through the top plates up into the heel of the rafter is also code approved providing you use the right screw and proper angle.  The screws are used in place of the hurricane tie, not in conjunction with.  Where your rafters span across the old exterior wall, hardware is not needed.  Toenails would be fine assuming the rafters bear on that old wall, and assuming I understand your situation.  Good luck.  

Those Simpson clips you show (post #214820, reply #4 of 7)

Those Simpson clips you show will work but are hard to work with and take lots of Simpson screws. I'd use a Timberlok screw or 2 in each one. No cheaper but worlds faster and will provide the uplift resistane you want. They are approved for that application.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

Thanks. So, if using the (post #214820, reply #5 of 7)

Thanks. So, if using the Timberlocks, I would drill straight through the 2x, or would I toe-screw it?

No need to drill at all. It's (post #214820, reply #6 of 7)

No need to drill at all. It's made to self drive so stick it in your impact and go.  I would drive it at the slope f the roof angle. but doubt it matters much.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

Got it! (post #214820, reply #7 of 7)

Thanks for the help (florida and everybody else who chimed in). I think I am straight now. As for the other end of the rafters, yes... I am using proper hurricanes for that, plus blocking between all the rafters so that end should be good.