Question on shed style roof and beam

[midrover170]

Hi all -

First, I'm quite the rookie on here - forgive me for any obvious ignorance! [I realize I may have posted this in the wrong place at first - sorry]

Next spring/summer I'm planning to start building a small 550 sf off-grid cabin. Wanting to do most on my own, so that's the reason for my simple design and layout. I have a number of questions about the framing, but one that worries and/or stumps me right now is at the roof where I anticipate using a glulam beam for mid-structure support. The cabin will have a 3:12 pitch running the distance. In the middle of the span is where I plan to frame in and install the glulam for rafter support (attached a couple pictures). As you'll notice in photos, I can't carry the angle of the rafters across the beam (unless I do some seriously strange notching).

What's typical here? Is the space (about 5 inches across) minor enough that the sheathing will provide strength? Do I need to have beam machined to match the 3:12 slope? I'm planning sheathing with metal roof, so there'll be strength for sure. Just want to avoid any major bonehead moves.

Thanks!

[SouthernTier]

I don't think you need to worry about that "area of concern".

Unless you need the headroom, I would suggest lowering the glulam and resting the rafters on top of it.  Otherwise, you'd probably be looking at joist hangers for each of those rafters, and they add up quickly cost-wise.

[cbrian]

I agree with SouthernTier, you will definitely save some money letting the beam carry the load rather than hanging the rafters in brackets, unless you are going to toenail, which you should not do on low pitch roofs.

Just out of obscurity why did you choose to sheath under a metal roof? Not sure what part of the country you are in, but in Texas we use 2 x 4 lathing on 2' center screwed down to the rafters (creates nature venting). The reason I mention it, if you do decide to hang those rafters, lathing will stand taller than gap you have there.

Note: here is an interesting article on 2x lathing http://tonylsmith.hubpages.com/hub/Got-metal-roofs-questions