Your contractor will know.

But, seriously, just google it.

Blocking the walls means adding support at the point where the grab bars will attach. This should be done when the wall is open (no drywall) and can be done as simply placing a 2 x 4 with the wide side out between 2 studs if that will match the bolt pattern you need for your grab bar. You may need to add more than one, depending on the length and orientation of the bar. Basically, it's just added in 2 x 4s to hold the grab bar(s).

Thank you, Suzanne. I’m just trying to educate myself on grab bars & placement issues that have been discussed in the forum. Before the walls get covered up, I wanted to be sure the blocking is exactly how & where it should be. Even though I adore our GC, there’s always a possibility for miscommunication. Now that I know, I can have a knowledgeable talk with him. Just to clarify, it’s not secure enough for the grab bars to be mounted into the 2 inch “side” of a 2x4 - it should be the 4” wider side, correct?

As far as I know, you can mount into the 2" side, the only problem is you have to be really accurate with where the screw goes in. It's really easy to not be dead center and you've only got 2" to work with. Your GC will know if he's comfortable doing it that way or wants to add in extra board. Adding extra is simple and quick.

I understand now. Thank you SO much!

Let in blocking uses half lap joints in both the studs and 2x6 (always 2x6) horizontal blocking material to allow the blocking to be on the same plane as the studs. Its the most secure type. It’s all glued and screwed together. You’ll have about 5” of very secure target space into which to attach your grab bars. Let in blocking can bear very large weights. Which is why it’s the recommended choice over toenailed blocking.

This is standard toenailed blocking, not let in blocking. The AARP has a free pamphlet on aging in place that includes illustrations of let in blocking, but I’m not at home currently to access my files.

Certified Aging in Place Specialist.

Wow, great info! I’ll try to find that on line, but I would also appreciate it if you’d send a link when you get home & have time. From the diagram, it appears that grab bars should be placed horizontally at 34 1/2” above the finished floor (right?)

Good food for thought, thanks!

My tile pro just blocks all around the shower with 2x6s as a matter of course. We didn’t put in a grab bar yet, but we measured and took pictures, so we can install one or more if I ever find a style I like.

Here's a picture. The obviously-in-progress shower has been stripped down to the studs (or maybe it's a new build -- I don't know -- I took it from Google), and the contractor has placed a narrow-but-solid row of solid wood between the studs. This will allow him to screw grab bars directly into the plywood. Note that the wood is at a comfortable arm height.

One more thing: Have the grab bars installed while you're building the shower. My shower started leaking /grew mold where the one set of grab bars was poorly installed. The rest of the 50-year old shower was in immaculate condition behind the solid-surface material.

Thanks to all of you for your comments, advice, photo & diagram! Framer comes back Monday afternoon to do the blocking. Being able to understand this process is a big relief!

We use either a 2x8 or 2x10 centered at 34 inches above the finished shower floor height. This allows for a greater strike zone when installing the grab bars.