I am in the process of framing a roof addition (no trusses). The new roof is an extension of the present 4/12 hip roof. When tying the old roof with the new roof, is it correct to add a base plate (3/4 ply or 1X6) between the new jack rafters and the old roof sheathing. The old roof uses 1X material for the sheathing. In Tauton’s book on framing it shows an individual using a “plate” between the new jacks and the old roof for support – is this correct? If it is, why is the plate necessary? Is it allowable to nail the new jacks directly to the old sheating, lining them up with the old jacks? Any advice would be greatly appreciated. Thanks, Bill
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Usually it's easier to use a 2x6 plate. Think of it as having the same function as the sole plate in a wall partition.
It'll help transfer the load of the new roof across the old roof instead of having several point loads. It also makes it somewhat easier to layout the new rafters.
If your current roof is as sturdy as you describe and you stack the new rafters over the old, no, you don't neccessarily need the 2-by base plate for the new roof.
Still, it's not a bads idea.
Thanks for the information. Where I live (MN) it was extremely difficult to get construction grade fir for the rafter framing. It turns out no one hand frames roofs anymore and everything is trusses. Anyway, do you know if it is ok to use just a standard 2X6 (ie Menards quality) for the plate or must it also be fir? Since it lays flat it doesn't seem to me to make a difference but I would appreciate your opinion. Thanks, Bill
I don't know what Menard's carries, I'm on the east coast. There are a few varieties of commonly accepted framing lumber. I'd venture a guess that if Menards is sellling it as lumber, it's suitable for framing.
I am sure that there are still plenty of stick framed roofs in MN. In any event there is still plenty of floors framed with solid lumber. Doug fir is a premium framing material but it is not available in our area except by special order. Our standard lumber is all spruce and while it is not quite as strong as fir this is rarely a problem except with very long spans. If need be, you simply make your framing deeper. Except for floor joists and rafters, framing lumber is usually much stronger than necessary for structural needs.
I think you are talking about gable studs? Jack rafters are the graduated rafters that are used in hips and valleys. Your roof will be on top of an existing roof and you need to close in the end? If this is the case then yes, put down a bottom plate the same as your stud thickness, 2x4 or 2x6. What will you nail your sheathing to without it?
I thinks he's talking about a California or layover valley. The framing member in question is the sleeper.
As "da pig" said it is called a sleeper. Also, sometimes called a valley board. If you leave it out, it's big trouble come inspection day (where I live).
Re large dimension lumber not being available in Minnesota, on a recent visit to that state, I walked through several tract built under construction homes in a couple of neighborhoods since my cousins were interested in buying a new home. Kinda neat to see the different building methods and materials being used in that part of the country... I noticed in several cases the stair stringers were other than 2x material. See attached pic; looks like thick OSB... My guess was that it was rim board material like what would normally be used on an I-joist floor system. I also saw a lot of trussed floor systems, and I think I even saw 2x3s being used as roof truss members. Of course, these were tract houses.
I think that is the LSL material that Weyhauser markets for stair stringers. I've seen it at building shows and the biggest pro is that it is perfectly uniform and will not split.
I don't like the 2x treads though.
I think the 2x treads are temporary. What does LSL stand for? Laminated Strand Lumber? No splitting sounds good as I was wondering about the edge nailing wneh attaching the treads/risers. Generally, OSB doesn't like that...Matt
I get to take the day off today. I've been fighting some kind of cough for a few days and my sister is giving birth this morning :-) It'll be my first neice. I'm just getting ready to leave in a few minutes :-)
Ok, not that that had anything to do with stairs . . . here is a link to the brochure for the LSL. I've been dying to try this stuff for awhile. I'll get to soon I hope. I hope this helps.
http://www.trusjoist.com/PDFFiles/2123.pdf