Stud Wall Bridging Requirements

[JAE]

Somewhere, in some document or code, I recall seeing a requirement that any stud wall framing over 8 feet in height would require the addition of intermediate lines of bridging to keep the unsupported stud length < 8'.

I cannot find this provision, tied to the 8' length in any code. (looking at U.S. codes)

In the IBC 2000, section 2308.9.9 seems to require an h/t limit, but I can't recall where the 8' criteria came from.

Anybody know where this is?

We had it on a set of older plans and now that its getting built, we can't justify it off of the current code.

 

[SlideRuleEra]

JAE - I don't have an answer, but do have some clues that might help:

"Wood-Frame House Construction"
US Department of Agriculture Handbook No 73, By L. O. Anderson, first issued in 1955.

A quote, taking about balloon construction: "In most areas, building codes require firestops be used in balloon framing to prevent the spread of fire through the open wall passages. These firestops are ordinarily of 2 by 4-inch blocking placed between the studs (fig 35) or as required by local regulations."

Figure 35 shows the firestops at the "2nd-floor joist" elevation - probably the 8 ft. dimension you referenced. There is no reference to keeping the unbraced length to 8 ft or less, but the "appearance" of the firestops is exactly what you have described.

Maybe a review of pre-1955 "big city" building codes would turn up something. I don't have access to any myself.

 

[JAE]

I appreciate the reply.

I do seem to remember that it was in a code....like the UBC or something, where I saw it...more of a recent code, and I put the requirement in our "standard" notes to use in the future. Now I'm trying to validate the requirement.

I've been in the business for some years....but not since the 50's. I was riding a tricycle then.

I'll keep looking but I distinctly remember it as a code requirement in an obscure paragraph somewhere.

 

[boo1]

JAE, we also use blocking for the plywood joint, and to increase stud stability.

 

[boo1]

IRC2003 - table 602.3(5) - 2x4 wall , bearing wall laterally unsupported , 10' - non bearing laterally unsupported , 14' and at plywood seams if used for seismic structural walls.if your not in a seismic area you would need blocking in bearing walls 10' and greater and non bearing walls 14' and higher.

 

[boo1]

'97 UBC section 2320.11.8 is the height to least thickness ratio of 50.

 

[JAE]

Thank you much (especially boo1)

 

[boo1]

JAE, I look up to you as a professional. Any time i can help you, it makes me giggle....

The depth of knolodge some of u guys have, makes me realise my own lacking.

 

[AlohaBob]

I see a limit in 2308.9 of 8 ft.

 

[JAE]

I don't see it - which specific section is it in?

 

[AlohaBob]

Oops 2308.9.1

 

[Ron]

JAE...the 8' requirement in 2308.9.1 applies to UTILITY grade studs. Table 2308.9.1 gives 10 feet for max. unbraced length.