How to frame L shaped stair opening
I’m in the stage of drawing the framing plan for my own build this year. I’ve ran into a problem where I don’t know what’s the best way to cope with it. Having no experience in staircase framing, I can’t seem to find any instructions outlining the available method for dealing with this rather common scenario. My exterior walls are 2×6, I’m using open web joists for the floor.
The stairwell opening runs parallel to the joists lengthwise. The L shaped staircase is located between two load bearing walls, with the landing side adjacent to the right one. The other side, the one where the staircase reaches the second floor, requires an LVL or something forming the “T” intersection.
My question is, since the LVL will be butting against the 2×6 Knee Wall it cannot sit on the top plate as in the case of a rim board where you have room, what would be the best practice here? Methods I thought of are:
1. Hanger ( is it possible here?)
2. Notch the knee wall or break it here for the LVL to come in (would this compromise the integrity of the wall? It’s shown in the attached 3D model photo)
3. Triple the top plates beneath and use wider lumber to create a ledger for the LVL ( my concern is that it would get in the way of the stringer and create an unsightly bulge in the 1st floor ceiling)
Replies
Hanger. You will have to build-up the wall studs underneath it, all the way to the concrete stemwall.
Simpson has metal pieces for all your needs on this build.
I see. I will check out what Simpson has for this, perhaps I can consult my floor joist company for specs too.
I heard back from my truss company designer, they told me due to the stairwell's long side being placed along the exterior wall therefore no subfloor is there to tie the wall to the joists, I ought to erect a wall from the basement mudsill all the way up the the 2nd floor roof truss in order to provide the necessary structural integrity.
I'm trying to come up with an alternative that avoids such practice as I consider it to be rather impractical to carry out. I'd need to use 19' stud, I have no idea how I'm going to be able to handle such long lengths of LVL.
Does anyone have experience with such design? I take it that it's pretty common place to see a staircase being aligned with an exterior wall on its long side, 8'-6" on the 1st floor for basement staircase ; 7'-6" on the 2nd floor for 1st floor staircase.
Yes, engineers call that out all the time b/c the floor braces the wall. If there is no floor in place and you are stacking wall on top of wall there is a hinge point. It is much stronger to balloon frame those walls and often are called out for 2x6 or greater b/c of tall wall height, 2x4 isn’t usually acceptable. I have seen homes w/ walls built as you are suggesting and I have had to repair a few of them on remodels to make engineers happy. I basically ran uninterrupted posts from top to bottom at 4’ centers and engineers signed off on it, but every engineer and inspector have their own ideas on what is right.
Balloon construction is the appropriate method here.
Just as important is the fire blocking now that you have two-story channels just waiting to send flames between floors.
And don't forget to tie the standard wall top plates into the balloon wall properly.