Garage with apartment above

Hi. I'm planning on building a garage 28'x36' with a 12/12 pitch roof. I expect the room upstairs to have what I guess would be called "knee walls". I was at Lowes and they got me a quote on trusses but didn't get me the dimensions, so I have no idea how high the knee walls would be. What would be a common height of knee walls? Or a range of different heights applicable.

With the 12/12 pitch, I assume that for every foot high the knee wall is, the room will be 2 feet narrower then the 28' garage width. (compensating for both sides)

Thanks for any help or suggestions.

I was also looking at local model garages from a company that only builds garages. They had a 24' wide one with 3 foot high knee walls directly above the first floor walls, then the roof on top of that. I forget the pitch, but the roof framing was 2x10's going to the peak, with 2x6 collar ties 9 foot up from the floor. So the angled part of the ceiling went from 3' to 9'.

Maybe it was plenty strong, but to me it looked like it would eventually sag. Especially with the weight of drywall up there. (the model was not finished inside). I was thinking of doing almost the same thing, but the framing would be balloon style with 12' studs on the first floor and the floor/ceiling joists would be at about 8 feet. That would give the little knee wall a hell of a lot more strength to prevent it from sagging and bowing out. Am I worried about nothing or does the need for more strength sound like a good idea?

Thanks, Tony

Reply to
Tony Miklos
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84 Lumber used to have kits. Might check with them. What about a gambrel roof. Would give you more floor space. my2cents.
Reply to
Bill

, so I have no idea how high the knee walls would

a knee wall is what you make it, any height you want. With 12/12 pitch and no knee wall you will loose 6' of useable all the way around the room, (considering anyplace the ceiling is less than 6/' high) making your usable room 16'x24' less your stairwell area. Making your knee wall higher gives you more floor space. Ass far as sagging or bowing, make sure you have your project engineered and built correctly, you should have no problems whether you balloon frame or not

Reply to
kickstart

It seems you are confused about "attics" in conventional framing versus trusses. In conventional framing the kneewall is a wall over the exterior wall raising the roof framing to get the desired usable space underneath. Partition walls are built within the attic space to define the usable space and minimum ceiling hieght. So your idea of ballon framing to 12' and installing the floor joists at 8' would work. With trusses the kneewall and the partition walls are built into the truss and are both structural elements. The room width would be 1/2 of the truss span, although I have designed attic trusses with attic rooms up to 2/3 of the span. Consult with the truss manufacturer. To insure you get what you want out of a trussed attic, draw a profile including the ceiling hieght, the room width and the minimum head room desired. Then try to talk to the truss designer assigned to your project. Unfortunately salesmen do not usually know that much about the engineering.

Gmduggan

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T> Hi. I'm planning on building a garage 28'x36' with a 12/12 pitch roof.

Reply to
GMDuggan

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