Just looking for additional insight on this.
This 2x4 blocking/bracing was installed in random locations throughout the house. It was installed on some interior and exterior walls, but not on others. I can’t seem to find anything in the code book that resembles this technique. And based on the random locations…it did not appear that this was blocking for installing cabinets/light fixtures, towel bars, etc.
Thanks!
It doesn’t appear to be a wall bracing method, at least any that I am familiar with.
It does appear small to be blocking/backing and for something. But what?.. I have no idea.
Sometimes that method is used to straighten a bowed stud.
Yeah, Scott, some poor quality framing there I see. 
I am curious about this membrane. It is not something I see here in GA. Why is it behind the sheathing?
Strengthen or straighten?
The stud is strengthened when straightened.
Looks like the bottom of the vapor barrier from here Brian.
Probably an exterior vapor barrier of some sort for the foundation. Just a guess. . .
@kleonard beat me to it…
The sheathing ties everything together, Without sheathing wind braces are required.
https://www.ncosfm.gov/residential/0602-table-r60231-straightening-bowed-studs/open
In my state, there is a standard detail for fixing bowed studs. Too bad builders can’t follow directions and get it wrong most of the time. 
About as close a guess as anything, but in my opinion it was a poor attempt if that is what it was for. Notching a 2x6 only 1-1/2" deep will not weaken it enough to take a bow out of it if that is what they were trying to do.
Typically a saw kerf in the middle of the bowed stud would be made about 2-1/2" and pulled to staighten and install a wood wedge to hold it straight and then scab it with at least a 2’ piece.
If the intent was for siffening, it was an even worse attempt. LOL
We used to straighten the studs as we applied the sheathing…while the wall was on the deck.
Am I the only one whose eye starts twitching like Inspector Clouseau’s boss when I see framing that is new and CROOKED!!! Geezus, you had one job. Use a damn square!
First, why. Second, why. Third, why do it crooked!
It’s possible it was straight when nailed in place and took a bend a week later. I’ve been a carpenter for 3 decades and the lumber we’re getting now is notorious for doing just that.
I was specifically referring to that mystery crosspiece. It’s clearly attached at about a 2 degree angle.
I have also done a lot of carpentry and you’re absolutely correct about the lumber. Heck I planed off about 5/8 of an inch off of a 2x12 for a newel post top. It was sorta flat when I bought it, but I planed it completely flat. I let it dry for about a month. I measured it at about 14% moisture. A week after it was on top of the post? Cupped again!!! I ended up starting over with a new board. Frickin annoying.
Gotcha. I’m trying to build a fence for a client but it’s 100+ degrees every dang day here in OKC, and I’m too old for that, my treated 2x3 uprights for this horizontal fence have developed the habit of turning into fishhooks.
ᐧ
That’s some quality lumber, Mark. 
It’s to keep the plywood from wicking up moisture from sitting on the concrete. It hangs out on the outside and is lopped over. It goes all the way around the house and then the plywood is installed. It used to be a thing but I haven’t seen it in a while.
Thanks Ray! Looks like a good idea since non treated wood should not contact the concrete.
