Most states and counties have adopted the International Residential Code. If you update your profile to show your general location, folks may be able to assist you in determining what the reference code is for your area. Assuming there will be some permit required for construction, you will likely have to comply with a code of construction. Marimbob, welcome to the forum! The beam you're describing is essentially the header over a two-car garage door in a load-bearing wall. Scabbing on some 2x's probably isn't going to keep it upright if the ground is moving under it. Bracing this structure needs a lot of thought. The truss shop might be able to help with design as well. LVL's or a glulam beam are other options. I finally passed at 4 ply 2x12 in #2 Hem/fir. Anyone can sell a plan, we don't know the source but I'd take that as a note of caution on what you have. This is why its not a good idea to reverse engineer a plan. it fails miserably, looked kind of dubious. I've written some of those equations into javascript to make it easierĮnter load, span (I used 180"),actual dimensions (I used 3 x 11.25), Fb 1124, E 1.3, Fy 172.5 There are beam design equations at awc.org, their publication DA6 Times the load (25 psf dead +10psf live)=5118 lbs This gives us the tributary area in square feet loading each beam. Take half the building width plus overhang, 9.75', times the span ~15'. I can't help with the seismic, you are likely going to be required to have this fully engineered when you permit this.įor the gravity loads the front end way to size the beam is A ridgebeam is heavier and typically is supported at each end and often along its' length by posts. A truss or gusseted together rafter set accomplishes the same thing structurally. Typically what you see is a ridgeboard that is non structural, it is simply something to nail the rafters to and carries no load. There is a difference between a ridgeboard and a ridgebeam. One day I'd like to make a complete materials list, go to the lumber store, and say "deliver this to my place" and be done with it. I tend to reverse engineer projects because I try to use the materials I have on hand. 9 trusses and 16 panels should only weigh a fraction of the weight of 1220 feet of 2圆s, so the 2x12s may actually be over kill. What I have to use are trusses made of 2x4 stock, and 2'x10' panels of metal roofing. That seems really heavy to me, and doesn't include roofing. The plans I bought call for 2圆 rafters with gussets, but (oddly) no ridge beam, on 24" centers, and the roof "sheathing" is 50 2圆x20' boards. I would rather wait until I can fit the necessary beams in my budget. I was hoping not to resort to a 6 post structure, mainly to give it a more open feel. The trusses I have are just shy of 4/12 (3.8/12) and there is a 2 foot overhang on each side of a single gable. The city code here in Olympia WA specifies a snow load of 25 PSF, unless it's a low slope as in a carport. I was sure your numbers were right, so I kept at it until mine came out the same. so I had to spend a little time decoding your equations, as well as getting a (very) basic understanding of the terminology. It's been a while since I was in advanced algebra/ trig.
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