Reinforcing The studs in stud walls
2

Question

Reinforcing The studs in stud walls

Wasib Jamil (Civil/Environmental)

(OP)

4 Jun 20 20:04

Hello Everyone,
I am working on 2 story and a roof framing addition on a single story building. The code to be used is International Residential Code which says that in order for addition of two or more stories, the lower floor has to be 2x6 studs @ 16" O.C. The existing studs in this building are 2x4s @ 16" O.C. which the village is not going to pass. Is there a way to get around that problem? Can I sister it or somehow reinforce it so that city won't have a problem with it?

Thanks,
Wasib Jamil

phamENG (Structural) · Answer 1 · 2020-06-04 20:49:56

The IRC allows for the exercise of engineering judgment and analysis by a licensed professional, assuming that language was adopted by the village or higher authority when the rest of the code was made law.

It can certainly be done, but you'll need a structural engineer to do the analysis and design.

Wasib Jamil (Civil/Environmental) · Answer 2 · 2020-06-04 21:33:31

@phamENG, I am a structural engineer and have calculated the braces that I can provide at 1/3rd heights. I just didn't know if code would allow that. Thank you

phamENG (Structural) · Answer 3 · 2020-06-05 02:20:54

Sorry - you used the Civil/Environmental tag on your name so I wasn't sure.

The IRC is prescriptive, meaning you don't need an engineer or an architect to design the house. An unlicensed home designer can draw up plans referencing those rules and hand them off to a builder, the builder pulls the permit, builds the house, AHJ inspects it, and no registered design professional ever sees it.

Since you don't meet those prescriptive requirements, you can't use the IRC for that piece. The IRC gives you an out - you can be an engineer! You have to switch over the IBC and pull the NDS referenced there. Run through the applicable calculations from NDS for the stud wall - specifically compression, tension, bending, and combined effects for the studs, crushing in the sill plates, etc. If design stress is less than allowable stress, you're good.

bimr (Civil/Environmental) · Answer 4 · 2020-06-05 14:51:11

Generally, building plans have to be prepared by a licensed professional (engineer or architect) in the State where the structure is located.

You have not described what version of the IRC that you have to meet or whether the IRC has been adopted by the locality where your project is located. It is not possible to make a comment without knowing these details.

Building codes vary significantly between jurisdictions. 2x6 framing may be required for structural reasons but the more likely explanation is that it is required for better insulation. It's certainly not universally required; there is plenty of 2x4 construction going on still.

The Energy Code for new construction for exterior walls: needs to be minimum 2x6 or you’ll need to have rigid board plus batt in 2x4 walls. This may not apply to renovation work.

A visit to the building code official is necessary to see what they will accept.

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Reinforcing The studs in stud walls
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