New construction. LVL header flush with rafters versus rafters sitting on LVL header
I have an engineer working on the project who has expressed concern with mounting the rafters in between LVL headers, and attaching the rafters with hangers. He is recommending a traditional header and the roof system sitting on top of the header. It may be a misunderstanding on my part however I am not seeing an issue as long as members are properly sized and attached.
The project has clerestory windows along the hallway side which is also an exterior wall. It would be easier and more traditional ceiling height to frame the LVL header above the top plate and flush with the rafters as opposed to sitting on top. Doing it the former way would attached the rafters with facemount or top flange hangers which I suspect to be stronger than hurricane ties and rafters sitting on top. I am proposing applied overhangs on this project, the LVL’s would also serve as solid blocking to fasten the overhangs outside of the sheathing and through the LVL with hangers.
Any feedback is appreciated. Thanks
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I don't see an issue with that, pretty much what I did here.
I've also set the support posts inside the windows (top and bottom plate are wider by window thickness) which meant the whole thing could be a single window array. This means more glass area, no trim and flashing work between each window and on the top. Also puts the window closer to the overhang for better shading.
It is a bit more labor with the joist hangers but not too much. If the overhang is reasonable depth, that framing is also simple as all you have to do is extend the roof sheathing over the beam.
Do watch overhangs and shading, I went a bit too small with mine which extends my cooling season by about a month.
Thank you for the feedback. That is the look I’m going for. Here’s a detail my architect drew up. We’ve sent it to the engineer for review hopefully we can gain insight as to what the concerns are. Perhaps it was the applied overhangs as we have a lot of wind in the area, other than that I don’t see an issue.
This might help:
https://awc.org/wp-content/uploads/2021/12/AWC-WFCM2018-SummaryofChanges-180618-3.pdf
I the overhangs are small you are looking at option A which is pretty straight forward. You can add some extra shading if needed with the eavestroughs.
You can also bump up the roof sheathing thickness for more uplift capacity.
Your roof shows fluffy batts in-between the rafters, this only works in Zone 2 or 3 and needs a diffusion vent at the ridge. Colder climtes your only options are some exterior rigid or interior spray foam.
The load on the header is eccentric, meaning it's on one side only, which complicates calculations to some degree, and you are relying on nails rather than gravity. Engineers usually like to keep things simple but there is no reason they should reject your design.