High load ledger for roof–not aligned with band joist
I need to attach a ledger to the front of my house that will support the porch roof trusses. There are several challenges here (see attachments):
1) The ledger will need to sit about a foot below the band joist. The trusses need to be located at this level to provide some snow clearance for the second floor window. The trusses can attach to the band joist with HUS28Z’s, but that can change. The window has no room to move higher, and I don’t want to change the window.
2) I’m working with a 150 lb. snow load, so the load on the ledger, per linear foot, will be 680 lbs. (snow load plus dead load, trusses 24″ o/c, 4 foot tributary length).
I’m open to just about any structural ideas. Everything I’ve come up with either looks a bit shaky or is really expensive. Can I just lag screw like crazy into the 2×6 (24″ o/c) studs? Would added blocking help? I know inspectors are fussy about deck connections, and this load exceeds most decks.
Thanks for the help!
Replies
One hundred and fifty pound snow load? Are you in the Himalayas? Seriously, you need an engineered solution here.
Thanks Andy. That's not what I wanted to hear though ;) I'll be in Montana's Himalayas--West Yellowstone. The code says 135 PSF, but the inspector advised 150 PSF. I'm not going to argue...
BTW, I do appreciate your reply. It just tells me something that I was hoping to avoid. I've built other buildings, including the home we currently live in, but between the 150 PSF snow load, the -35°F heating system design temp, and thick insulation, this has been quite a challenge. I really appreciate those who are offering advice.
I've actually been to West Yellowstone. Bet it's changed in 40 years though! I've never regretted hiring an engineer, and they usually don't cost as much as I expect.
150 PSF does sound very extreme. Last year I was subcontracted to build a cabin in Norway on a mountain side. The European equivalent to PSF was about 70. The cabin was built to w/stand avalanches. Europe is reevaluating roof load design as with climate change they’ve found that the snow is getting much wetter and heavier, but even then they are only considering a requirement of an additional 10 PSF to the 70 in Norway. As Andy stated, you will need to consult with an engineer w/ loads that extreme. Or at minimum a call to your local code authority. Typically a print examiner will need to approve your structural design before issuing a permit. If you have inspections in your area, fairly safe to say you have a print examiner at your permit office that will tell you if what your doing will fly. No one on the forum can really advise on this as design criteria is very specified to your area. Unless, there is a builder on here from Montana, probably want to make a call to a local builder, engineer or speak more in depth with your inspector.
I hired an engineer. He offered to design the porch structure and review and revise the entire house and garage for $1,000. I'm thinking that's a pretty good deal, considering the time it took me to do the calculations that I've done so far. Thanks for the advice.
Good luck with the project. Post some pics as you progress!