[sdear]

I need to add 2 LVLs to my exposed beam cathedral ceiling to support the load of a new additions roof. The rafters are 2x8 on 24" centers and the roof pitch is 9/12. The LVLs are 1 3/4" thick so 2 of them nailed together will be 3 1/2" thick. I thought of notching the rafters so they would sit on the LVLs. The level cut would go 3 9/16" into the rafter and the plumb cut would go up 2 11/16". Does this remove too much rafter material or would it be ok???

Thanks for the help

 

[joecaption]

Got some pictures of the inside and outside so we can see what your seeing?

 

[sdear]

The LVLs would span from the outside wall on the left, to the 4X4 on the right.

 

[Daniel Holzman]

How did you determine that you needed two LVL's? How did you decide where to put them? From your description,you are adding a new roof, so presumably you are adding load. Before you get into the details of how to attach the rafters, you should review the design to make sure all loads are accounted for. If your engineer or architect designed the roof and the LVLs, you may want to start by asking them how they intended the rafters to connect.

Rafters are often attached to LVLs used as ridge beams using special metal hardware, Simpson (and others) make special clips for this purpose. But in order to select the correct clip,you need to know the loads the clips will carry.

 

[sdear]

As part of the building permit process, an engineer did all the necessary calculations for the roof loads. The placement was determined by where the new roof will intersect the existing roof and where an inside load bearing wall corner is . One thought from the plan drawer was to let the rafters just touch or kiss the LVLs. In my way of thinking, with the roof pitch being what it is, 9/12, the rafters contact with the LVLs will only be at the top corner edge. This doesn't seem the best to me hence my thought about notching the rafters. I will be talking to the engineer when he returns from vacation, but I'm still seeking advise from those that know.

Thanks

 

[123pugsy]

It leaves just over 2/3's.

 

[Daniel Holzman]

From your description, your engineer designed a ridge beam, not a ridge board. Rafters need to be positively attached to a ridge beam in a cathedral ceiling application such as you describe, which generally is done using special galvanized steel connector plates with appropriate fasteners. The connections are sometimes done using custom fabricated brackets if you need a particular look, say for a church using large format framing. I have never seen notched rafters used with a ridge beam, not saying it cannot be done, just I have never seen it.

You need to discuss this with your engineer, as part of their plan they should have designed the connections, which are critical to the success of the design.

 

[carpdad]

Birdmouth would be fine. Just make a template for same size and strike a line for same reference. You must anchor the rafters to the beam, though, which seems to call for a metal connector. Thinking of it as a new build, rafters may butt into a beam or sit on it with a notch.
Is the 4x4 already a structure or did you put it there for the photo? A beam wants to sit on a supporting structure. You can use a hanger but that must be engineered. Anchors for the hanger (bolts usually) will be carrying all that load. The 4x4 also seems to be little short of the rafters, at min will look like a mistake. Also have never seen a load bearing post standing alone as such. I suppose the rafters will lock it in but should ask the engineer who gave you the plan.