Half Wall / Knee Wall for shower

[SethAMG]

I'm pretty sure anyone that knows anything about framing half/knee walls is going to tear me apart...so here it goes...

I attached a pdf with 5 pictures of my framing "wonder" and was looking for pointers because I'm unsure whether i should move forward or not. I would be happy if the knee wall had exactly no movement, but it does tend to move a little with 30-50 or so pounds of rocking pressure (maybe a 1/4" or 3/8" total...not just one way). I'm guessing that if I cover it with 1/2" Hardi board that it would stabilize even more, but i'm looking for some good/constructive advice here since it will be tiled and I don't want any issues 10 years down the road (cracking grout, etc.). There will also be custom frameless glass installed (3 pieces: a door, a full length pane to the left, and a piece on top of the kneewall)

I have searched all over the internet and I can't find anything that helps to calm my nerves. The only good advice I've seen is the bolt idea from the top of the half wall down to a cross section in the floor joists and/or a 4x4 (also attached through the subfloor to a cross section in the floor joists). I would love to not have to tear out and get into the subfloor, so that's what i'm trying to get around. My last idea was to cut a 2x6 for a top plate of the half wall hoping that would tie it all together better...?

Should I just tear out everything to the full wall and start over with a new framing method? Any advice is greatly appreciated. Especially for the corners...how would one frame a 135 degree angle like that?

Oh yeah, I'm new here... HI! Thank you for all your help.

[Houston Remodeler]

Seth,

Welcome to the forum.

For attaching pictures, we prefer you click on the paper clip icon in the reply bar header.

If you used deck screws (and it looks like you did) that's about the best you're gonna get with that angled design.

I'd be tempted to use PL Premium between the CBU and the framing as well as the proper fasteners. Be sure to provide opposing force when driving the fasteners as not to bend the wall while installing the CBU.

Once the added layer of CBU, waterproofing, thinset and tile are installed, you should have a pretty stiff laminated construction. I wouldn't worry about it.

Your carpentry is rather neat

[SethAMG]

Thank you for the feedback! I was concerned that my half wall framing wasn't up to code or standard of some sort...

I used deck screws, but only 2.5"... I was going to go grab some 3" or 4" and replace a few at the angles just to ensure the rigidity.

I've never used PL Premium. Is Liquid Nails the same type of stuff? I definitely wanted to use some type of construction adhesive between my CBU and framing. Can I use PL Premium between my sheetrock and framing as well?

Also, is there a favorite CBU and/or way to waterproof in this forum? I'm guessing this subject has been beat to death in this forum, but is there a best thread to point to?

Thanks again!

[Lakee911]

Originally Posted by SethAMG

The only good advice I've seen is the bolt idea from the top of the half wall down to a cross section in the floor joists and/or a 4x4 (also attached through the subfloor to a cross section in the floor joists). I would love to not have to tear out and get into the subfloor, so that's what i'm trying to get around.

This is the best plan. I don't get any warm fuzzies from movement of a wall which is to receive tile.

The CBU will prevent racking, but that's going to be happening perpendicular to the large face of the sheet. That's not the movement that you're experiencing. Adding CBU to your knee wall is going to add a marginal, if not negligible, help to your wall.

If you think of your wall as a teeter-totter and apply a load, your pivot is so close to the other end that it takes a tremendous amount of force to counter the small load you apply at the other end (the top part of the wall). The tremendous amount of force is on the end grain of the lumber and the fasteners that are holding it in place. That's why it moves. By extending it through the floor you're making that small end of the teeter-totter larger. Now you've not only got more surface for attachment, but the force it needs to counter isn't as great.

Your project and your shower, but were it me, I'd rip it out and strengthen that sucker. If you can get to it from below, you could just cut out enough at the end of the wall to simply add a 2x4 that goes down through the floor to the joists or other suitable structure below. That'd do wonders.

[sepulchral]

I'm worried about the same thing (flex) with my wall.. .I'm going to triangulate to an interior wall and make a little "towel shelf"... Lag bolts into subfloor (watch your utilities) may help alot... The more mass the better.

[Lakee911]

I'm not sure what we're looking at there, Michael, but your plan sounds good for an attempt to eliminate the flex.

[Steve in Denver]

Originally Posted by Lakee

Adding CBU to your knee wall is going to add a marginal, if not negligible, help to your wall.

I was surprised at how much my wall stiffened up with cbu, kerdi and tile...I wouldn't have expected much of a difference...

When I was looking into it, here is what I found:

1. Double up the perimeter studs where practical.
2. Penetrate the floor with the outermost vertical stud and attach to a floor joist, if possible.
3. Penetrate the back wall with the top 2x4 and attach to the studs in the back wall, if possible.
4. Anchor the outer part of the wall to the joists using a threaded rod.

I did #1,#3 and #4, which all helped. I ended up having to remove the rod for plumbing reasons. In the end I think the CBU + kerdi + tile made as much of a difference as the other things I did. It's not solid as a rock, but it's pretty sturdy (24" wide, 82" tall)...I think I worried about it too much.

I attached a few pictures of the threaded rod support. Note the upside down joist hanger under the floor for transferring the force to the joists. This contraption definitely helped, but it's probably overkill, at least for my application. Again, I had to take it out for plumbing clearance reasons, and the wall seems plenty stiff without it.

[Steve in Denver]

I should add that in addition to the CBU on the knee wall itself, the CBU on the wall it is attached to helped considerably. This is because it prevents twisting of the "other wall" stud where the knee wall attaches...without something immobilizing the stud, it twists fairly freely allowing the knee wall to move more easily.

[Houston Remodeler]

The cbu plus PL premium plus screws makes a sheer wall with greater strength than the elements alone.

Somewhat carefully typed on teensy cell phone keys.

[sepulchral]

good idea with the allthread and bracing to the joist

[Steve in Denver]

I can't really claim credit for it, I found info here:

http://www.aconcordcarpenter.com/rei...pony-wall.html