My single-story house was built in the 1940s in the San Francisco Bay Area (Earthquake-country).

Here is a picture of the wall with the wallboard removed. This is from my neighbour’s house (Same vintage).

enter image description here

I am curious about the horizontal & diagonal boards in the wall. These are found in the interior and exterior walls. These are not called "Studs", because studs are vertical. What are they called? Bracing? Truss?

1 Answer 1


This is bracing that is needed for a shear wall. This provides lateral support, which is needed in areas prone to hurricanes and earthquakes. Typically, the plywood sheathing and drywall is all that is needed to provide shear support low risk homes. This kind of bracing is often turned on its side and let into the stud framing (notching the studs) rather than being placed between the studs and further braced above and below. There are also newer versions that are T shaped pieces of metal (maybe 10' long but only 1" wide or so), where the base of the T is inserted into a small notch that is cut into the studs and the top of the T is nailed flat to the face of the stud.

Note that the other bit of blocking at the top of your photo appears to be for the knob and tube wiring, which I hope you're in the process of removing/replacing.

See also: What is a shear wall and what is it for?.

Wikipedia entry on shear walls.

  • Much of the knob & tube wiring has been replaced, and I'd like to replace the rest of it. However, fishing NM cable is challenging because of the horizontal & diagonal bracing. I want to run the wiring through the basement, but drilling through some of that horizontal bracing looks particularly challenging. Sep 1, 2013 at 19:55
  • @StefanLasiewski - Drilling through the diagonal bracing should be a piece of cake for walls that appear as in the above picture. For walls that still have 60 year old wall board on them maybe it is a motivation to strip those walls too!!
    – Michael Karas
    Sep 1, 2013 at 20:26
  • 2
    There are long flexible extensions that you can buy for an electric drill that make drilling through lateral and angled braces easier. You do need to find the right location in the basement and drill a pilot hole into the wall cavity then insert the extension with a drill bit on the end. You do need to make sure that the power to the old lines is turned off first.
    – bib
    Sep 1, 2013 at 20:35
  • Thanks for the tips. Not sure I want to strip the wall just yet (I'm currently only installing one outlet), but maybe stripping this section and replacing with drywall will be less frustrating then drilling through a 45-degree piece of ancient (hard) redwood with a flexible drill bit. Sep 2, 2013 at 0:08
  • 1
    For more discussion on flexible drill bits, see diy.stackexchange.com/questions/25502/… Sep 2, 2013 at 0:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.