IÃ¢â‚¬â„¢m back with another question. IÃ¢â‚¬â„¢m redoing my girlfriendsÃ¢â‚¬â„¢ house working on the upstairs attic area. The room is 11Ã¢â‚¬â„¢ wide, a 17/12 roof pitch and knee walls 5Ã¢â‚¬â„¢ high. I want to move the knee walls back a foot but IÃ¢â‚¬â„¢ve run into a potential problem. Where the knee walls meet the rafters, rather than cutting the studs to match the rafter angle, the rafters have been notched about 2″s in and 2″s down to accept the knee wall studs by the original builder. IÃ¢â‚¬â„¢m afraid if I move the walls back without reinforcing the notched area in the rafters, the rafters could split if a heavy enough load (snow, wind, and so on) was put on the roof. What IÃ¢â‚¬â„¢m thinking is I would nail and glue a 4Ã¢â‚¬â„¢ 2 x 4 alongside the area of the rafters where the notches are and then IÃ¢â‚¬â„¢m going to nail 2x2s to the face of the rafters to give me a little more room for insulating. 6Ã¢â‚¬ of insulation isnÃ¢â‚¬â„¢t a lot but I live in a fairly mild area. Do you think scabbing a 2×4 to the rafter will reinforce the notched area enough to move the knee walls back where I want to or should I leave the knee walls where they are?
To answer your question in one word, yes. You are doing the right thing by scabbing in like that but do it on both sides of the 2x4 and use nails that are alternated in their nailing pattern. When you go to put in the 2x2's, use deck screws, or at least ring shank nails. Nails have the sheer strength which is what you need for the scabs and screws have the non pullout holding power.
A 2x4 rafter roof for a living space is an under built roof no matter how you look at it. You could go the route of scabbing in 2x6's all the way from the wall plate to the ridge and that would give you a stronger roof all the way around plus the advantage of the insulating space in one shot. A little bit more $$ but a stronger roof and sounder mind.
Hey Jer - when you say, "A 2x4 rafter roof for a living space is an under built roof no matter how you look at it." do you mean it's underbuilt strucurally, or doesn't allow for enough insulation depth, or...? Who's the cat that won't cop out, when there's danger all about?
Yeah, i'm thinking structural. Of course anything's ok if it's small enough.
You left out too much information...
What specie are the rafters?
spacing on center?
Lots of information is required to properly size rafters. since you are dealing with 2x4's moving a load point 12" could make all the difference in your life.... do you want your girlfriend moving in with you?
Many times when a knee wall is 'let-in' to the rafter like that, it's because it is designed to be picking up some of the load. It's more work to build a knee wall that way, so there's often a good reason why it would have been done like that.
Just double check yourself before you go and move it.
If you're in the clear and move it, then you've already got the right idea on the fix.