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I am trying to educate myself on the finer points of using engineered joists as roof framing members. In my market, trusses are used almost exclusively for roof systems. Recently customers are becoming more interested in utilizing attic space as living space or “bonus” rooms. We order trusses engineered to provide this space, but on more complicated roofs, by the time you mess around with them it seems like it would be simpler and cheaper to hand-stack the whole thing. Since the 2x lumber we get here isn’t all that great (unless you are building toboggans) I thought engineered joists might be worth looking into.
I have checked the design guides of Boise Cascade and other makers of I-joists, but they don’t address the questions I have. Hopefully some of you can help me out. These are my main questions:
1. Can I-joists be used in a gable-valley configuration? (ie. Can they be used as valley rafters and valley jacks or can they only be used as common rafters?)
2. If so, how do you connect the valley jacks to the valley rafter? Do they make hangers? Are they required?
3. If the birdsmouth is placed on top of the floor system, (as opposed to the rafter and ceiling joist being nailed together and nailed to the top plate) is a bearing ridge beam always required to prevent outward movement of the rafters?
4. Do you find this type of construction to have a benefit? (quality wise or economically)
I appreciate your help. I welcome any opinions or suggestions, and if I explained any of my questions poorly I will be happy to re-phrase them. I will try to talk to the engineer at Boise Cascade soon, but I would like to go in knowing what I am talking about!
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I am trying to educate myself on the finer points of using engineered joists as roof framing members. In my market, trusses are used almost exclusively for roof systems. Recently customers are becoming more interested in utilizing attic space as living space or "bonus" rooms. We order trusses engineered to provide this space, but on more complicated roofs, by the time you mess around with them it seems like it would be simpler and cheaper to hand-stack the whole thing. Since the 2x lumber we get here isn't all that great (unless you are building toboggans) I thought engineered joists might be worth looking into.
I have checked the design guides of Boise Cascade and other makers of I-joists, but they don't address the questions I have. Hopefully some of you can help me out. These are my main questions:
1. Can I-joists be used in a gable-valley configuration? (ie. Can they be used as valley rafters and valley jacks or can they only be used as common rafters?)
2. If so, how do you connect the valley jacks to the valley rafter? Do they make hangers? Are they required?
3. If the birdsmouth is placed on top of the floor system, (as opposed to the rafter and ceiling joist being nailed together and nailed to the top plate) is a bearing ridge beam always required to prevent outward movement of the rafters?
4. Do you find this type of construction to have a benefit? (quality wise or economically)
I appreciate your help. I welcome any opinions or suggestions, and if I explained any of my questions poorly I will be happy to re-phrase them. I will try to talk to the engineer at Boise Cascade soon, but I would like to go in knowing what I am talking about!