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How to connect rafters to ridge beam

BarbaraD's picture

My engineer has spec'd a 32-ft long ridge beam for the garage.  The garage is 20' x 32' and the shorter ends are gable ends.  Gable roof, with 8:12 pitch, 2x6 rafters 24" o.c., and fake slate weighing 475 lbs per square.  The ridge beam measures 5 1/2" x 14" x 32'.


He said to use Simpson RR ridge/rafter connectors to connect the 2x6 rafters to the ridge beam, but when I looked in the Simpson catalog, I see that the RR has a 90 degree angle, meaning that the ridge beam is rectangular in cross-section.  Well, my ridge beam is going to be beveled on the upper corners to match the 8:12 pitch of the roof, and I do see that you can bend the flange of the RR that rests on top of the ridge beam.  So does this sound ok to go ahead and do it that way?  Would I just hammer on the RR connector until the angle is 8:12?


Don't most people use joist hangers to connect rafters to ridge beams?  What about the seat cut?  You have to make a triangular notch cut in the bottom edge of your rafter in order for it to seat itself in the hanger.  Is that the way it's done?  At the end of the Simpson catalog they show hanger options (p. 165) and I was interested in those B Sloped hangers they show there.  The one seen at the bottom corner of the page would fit my situation.  So I'm wondering, what do y'all recommend?  Has anyone used these B sloped hangers, and if so, do you have to wait a long time to get them?


Any help would be appreciated.  Thanks.


Barbara

(post #99054, reply #21 of 42)

I just did a shed/garage with rafters 10' long (ridge to eave) 2x6 at 24" o.c.   It's rated for snow load and wind load in my area.  Pitch is 6/12.   I can't imagine you'll have a problem.

 

 

(post #99054, reply #24 of 42)

When you first mentioned 2x6 rqafters, my eyebrows went up, but then I assumed you must be from down south where that is the norm, not needing to design for snowloads. I looked at your ( thank you for filling it out) profile and saw that s cAL is your stomping grounds.

500#/square of roof materials is only 5#/sft, well within standard dead load design.

RE a toploaded beam instead of inset, you just lower the beam inside, it doesn't change the height of the building.

 

 


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Oh Well,

We did the best we could...

(post #99054, reply #25 of 42)

But I didn't want to give up the headroom in the attic; that's why.

(post #99054, reply #17 of 42)

I thought the same thing - but now I will keep reading to see what happens. . .

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Adventures in Home BuildingAn online journal covering the preparation and construction of our new home.

(post #99054, reply #18 of 42)

5 1/2 x 14 x 32'?  With 500#/square slate dead load plus whatever live load is there?  If this isn't steel, why isn't it?!  There's a place for engineered "lumber", but is this it?  Steel's gotta be cheaper for this job, and you'll need a crane either way, won't you?


 

(post #99054, reply #27 of 42)

Moltenmetal,


I just checked the lumber invoice, and it cost $504 for the 32' beam lumber.  I ordered three 1-3/4" x 14" LVLs, because there's no way we could get a one-piece beam up there without a crane since I have a big tree right next to the driveway, it blocks anything taller than 9 ft from going down the driveway.  The garage is detached and at the rear of the lot.  Only 9 ft of space between side of house and property line for something to get down the driveway.  That's why we decided we had to do a build-up beam.  Two of us were able to carry each LVL from the curbside delivery site into the backyard, and we were thinking at the time we'd have little trouble getting each ply into position at the ridge.


As for steel, I have no idea how much it costs, but a crane was out of the question.


Barbara

(post #99054, reply #22 of 42)

This is how I attached my rafters, and yes it is probably overkill.  Each rafter is attached to the ridge beam with an A35.  It is also attached to the opposite rafter directly, and it is also attached with an 18ga. strap that is bent around the two opposing rafters so that it is attached on three sides of each rafter.  The blocking between is attached to the ridge beam via two A34's (actually an A35 with the folded tab cut off), then they are toenailed into the rafters as well.


I will be placing a ridge vent over this, so those small angled blocks are there to provide a little extra support at the top of the OSB board, without blocking air flow.


Rebuilding my home in Cypress, CA


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(post #99054, reply #29 of 42)

Man what a complicated contraption that is to see!  It looks like your ridge beam is not one continuous piece.

(post #99054, reply #31 of 42)

The ridge beam is under the rafters - it is the dark brown wood.  It was also the only original wood I left when I replaced the garage roof.  All that new wood sits atop the ridge beam. 


Yes, it is more complicated than it could have been.  Unfortunatly, I endevored to replicate the system that was already in place when originally built, instead of thinking about how I could do it better.  If I did it again, I would have extended the top end of the rafters, then cut them off after all were set - it would have given me better connection to eachother and I wouldn't have needed that strap.  Heck, If I did it again I might use engineered wood I beams instead - wider surface to screw the sheathing into.


Rebuilding my home in Cypress, CA


Also a CRX fanatic!

YAY!  I love WYSISYG editing!  And Spellcheck!

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(post #99054, reply #33 of 42)

 


Is it all screws?


How many weeks did this take?


Way too complicated.


Joe H

(post #99054, reply #35 of 42)

If you look closely you can see that pic is not real - it is one of those deals where someone digitally diddles the pic to make it look like something it's not... you know, like the one with president's Bush's head on a woman's body... :-)


 

(post #99054, reply #40 of 42)

Yep, all screws and it took about half a day.  I used about 1000 screws (the specific ones I had talked about before)  My inspector thinks I must own stock in Simpson... and McFeelys.


What about it seems complex - it's perfectly straightforward for me!  Now watch me walk a straight line for you officer.


Rebuilding my home in Cypress, CA


Also a CRX fanatic!

YAY!  I love WYSISYG editing!  And Spellcheck!

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