Detached garage side wall
What's wrong here?
- The let-in brace is much flatter than the 45 to 60 degree angle Method LIB requires
- The IRC no longer lists let-in 1x4 bracing as a wall bracing method
- A let-in brace must slope down toward the near corner of the building, not away from it
- Nothing. This installation is compliant
Show the answer and the code reference
The answer
The 1x4 let-in brace runs at only about 30 degrees from horizontal; Method LIB requires a 45 to 60 degree angle, so this brace does not count as a braced wall panel.
Correct choice: 1. The let-in brace is much flatter than the 45 to 60 degree angle Method LIB requires
Every braced wall line needs braced wall panels built by one of the methods in R602.10.4. Table R602.10.4 describes Method LIB (let-in bracing) as a 1x4 wood brace, or an approved metal strap, set at 45 to 60 degrees from horizontal in walls with studs no more than 16 in. on center, let into the studs and plates and nailed at every stud and plate. The brace here drops one 8 ft wall height over roughly 14 ft of wall, about 30 degrees. That is outside the method's tested and tabulated configuration, so the panel provides no credited bracing and the wall line comes up short against the bracing length required by R602.10.3.
How to fix it
Remove the brace and install new 1x4 let-in braces at 45 to 60 degrees (an 8 ft wall needs roughly 4-1/2 to 8 ft of run per brace), let into the studs and both plates and nailed per Table R602.10.4, in the locations and total length R602.10 requires. Sheathing the wall with wood structural panels (Method WSP) is the more common modern fix.
Code references
IRC 2018 R602.10.4 — Construction methods for braced wall panels
Intermittent and continuously sheathed braced wall panels must be built by one of the methods in Table R602.10.4. For Method LIB the table calls for 1x4 wood or approved metal straps at 45 to 60 degree angles, studs at most 16 in. on center, with the brace nailed at each stud and plate.
Drills citing R602.10.4IRC 2018 R602.10 — Wall bracing
Buildings must be braced per R602.10 (or R602.12 where applicable); braced wall lines need braced wall panels of the required length and location, built by a method listed in R602.10.4.
Drills citing R602.10
2024 IRC:same rule and number. Search results quoting the 2024 IRC still describe Method LIB in Table R602.10.4 as 1x4 wood or approved metal straps at 45 to 60 degree angles for a maximum 16 in. stud spacing. The full 2024 text was not reviewed. Confidence: medium
Minnesota
Minnesota adopts the 2018 IRC with Minnesota amendments as the Minnesota Residential Code (Minn. Rules ch. 1309). Search results indicate Minn. Rules 1309.0602 amends part of R602. The only text found (continuous exterior sheathing, bracing per R602.10) appears to belong to a tall-wall stud provision, not to the bracing methods, but the rule could not be opened to confirm that R602.10.4 and Method LIB are unamended. Either way, the brace shown does not meet Method LIB. DLI is adopting the 2024 IRC as the next edition; see the 2024 IRC note.
About the Minnesota Residential CodeWhy the other choices are wrong
- The IRC no longer lists let-in 1x4 bracing as a wall bracing method. Method LIB is still one of the intermittent bracing methods in Table R602.10.4 of the 2018 IRC, usable within the wind, seismic and wall-height limits of R602.10. It just has to be built as the table describes.
- A let-in brace must slope down toward the near corner of the building, not away from it. Table R602.10.4 sets the brace size, angle, stud spacing and nailing, not which way the brace slopes.
- Nothing. This installation is compliant. Table R602.10.4 describes Method LIB as a 1x4 (or approved metal strap) at 45 to 60 degrees; at about 30 degrees this brace does not qualify as a braced wall panel.