i joist framing of a second floor with different wall heights.
We are thinking of adding a second story above our attached garage or to the side of it.Above we gain aprox 480sf of living space to the side we would gain only 220 and would need to pour footings and a stemwall. Above the garage remove the roof and frame a floor. The problem is this the shortest distance would be to run joistsexterior wall to interior wall, TJI 210 11 7/8 would fit the bill and clear a span of 19′ 8″, running them back to front would requireTJI 560’s 11 7/8 at about double the price to span 23′ 5″ clear. I do not want a beam down the center.
To the problem, all of the three exterior walls are 8′ the ajoining living room wall is aprox 10′. I do not want to reframe this wallso is there a way to hang the joists off of the taller wall with a ledger board say lag screwed to the studs. Then use joist hangersto hang the I joists? Has any one ever seen this done, almost the way one would hang a deck ledger board? I looked at severalI-joist web sites for a cross section framing diagram similar to what I am thinking of and can not find anything close. I would like to stay to a 11 7/8 joist. Also if I went the longer direction the header above the 16′ garage dooy may need to bebeefed up too. What would the ledger board would need to be made of rim board, mirco lam? Yes this might need to be engineered. Just lookig to see if anyone has seen this done.
Wallyo
Replies
It can be done
I'm certain it can be done. It is not a "standard" installation, so you won't find a standard detail on how to do it.
You might have to hire an Engineer to review the existing wall, and draw up a detail on how to tie it all together before you can pull a permit.
You have great need of a professional designer and engineer to help you with sorting out where your "I want"s are running head - on into reality
You have great need of a professional designer and engineer to help you with sorting out where your "I want"s are running head - on into reality
Two things come to mind.
I-joists that span 23' are way too shallow at 11 7/8" deep. I don't care what the span charts say.
Yes, a ledger board support is possible. But you're transferring a hell of a lot of weight to the wall. You'd need an engineer to spec the connection for you.
It would most likely be easier and cheaper to re-frame the walls.
Boss thanks as always for your insight and knowledge.
"But you're transferring a hell of a lot of weight to the wall"
That is what I keep thinking of there would be a downward force but also an outward force on the ten foot wall perhaps bowing it inwards.
As I was posting my question I kept thinking back to something I did several years back on a job, but not exactly like I am thinking of. Had a second story with 8' 6" ceiling, the joists were 2x6 spaning about 13 feet. We put 2x6 blocking above the top plate. Attached joist hangers to the blocking and hung 9" i joists between the 2x6s', jacking the bowed 2x6's up as we went along. All approved by permit, but the blocking was installed above the top plate.
I keep going back to a deck though, which are floors hung off the sides of house by a ledger board. Not too different from what I have in mind, but unlike a deck I have a longer span.
"I-joists that span 23' are way too shallow at 11 7/8" deep."
Among other things that is why I like the shorter span of 19' 8", my 8 foot wall to 10 foot wall. In this direction running elec and venting would be a bit easier. There is one place where a wood framed fireplace chase butts out into the garage two foot making the span 17'8" for five feet in the middle of the 10' tall wall. Here it would be easy since the wall in that area is 8 foot it ends at the garage ceiling.
Yes to all I realize engineering may be needed to obtain a permit, It is just before committing to this idea I am looking for creative solutions or someone who has seen something similar done. If needed I do not mind paying an engineer but I am also cost comparing the two Ideas, build above or on the side. I found it is sometimes cheaper to ask an engineer will this idea flyand as Boss say spec the connectons then it is to say tell me how to do this from start to finish.
LIke instead of reframing the wall can a ledger be notched into the ten foot wall, and the joists hung off of that.
Thanks to all
Wallyo
I do not want to reframe this wall
Why not? The wall may not be strong enough to bear the load anyway, and it's possible that the reframing could be done with minimal effect on the inside finish.
"Why not?"
The ten foot
"Why not?"
The ten foot wall is shared with the living room, it is finshed and sheetrocked. I am trying to limit and destruction and construction to the garage side of the wall so as to limit disruption to the living space side. The wall is on a proper footing and stem wall to support a second story. It is doug fir framing, 16" on center with fire blocking at the 8' garage ceiling hieght. So it should have no problem supporting the load.
I admitt one might be able to cut it down to 8' put a double top on and have the sheet rock stay intact. without damaging it too much I just am looking for the least disruptive way to do this.
Wallyo
Don't pay too much attention to Dan. He feels compelled to write something, whether he has a clue what he is talking about or not.
Piffin, I've actually done what I described, on a smaller scale. It may not be the best solution, but it's a workable one.
U wanna pat on the back?
Dang Piffin, you discover those weren't raisins in your oatmeal this morning?
Rather than re-framing the wall, could you run the I-joists nto the wall and put a couple of studs under them?
That would take away the ledger issue.
I was thinking the same thing. The issue would be the fine print in the code on how the joists must be supported, I suspect.
That is one I did not think of ! A little heavy in the wood dept and labor, each 210 I joist being 2 1/16 wide would require double 2x's under it sistered to a stud. Then it is just a matter of fastening it in some fashion at top and bottom, may also have to jam in blocking the height ot the I joists between the next stud and i joist, and add web stiffeners the ends of the joist.
Wallyo