Structural independence of townhouse unit

[Glenn]

I find exceptions 2 and 4 of 2021 IRC R302.2.6 to be difficult to interpret sensibly. I would like opinions about the term "common wall" in these exceptions when the "common wall separation wall design method" is a complete and entire exception in #5. Are 2 and 4 not meant to apply to the "double wall method". I would like opinions that are formed from more than just "reading the current book". The current book appears to be clear in using the term "common wall". However, this section is a mess from two decades of code modifications. I have done my research so this is not an ill-prepared video or question. Townhouses began as just single family homes with zero FSD. They have become so different now, but the language in this section is dated. I have a hard time believing that flashing for shingles is going to pull down the second double wall, but the IRC reads that way.

I will be preparing a proposal to clean up the presentation of the townhouse sections in the 2027 IRC. I would like your educated opinions about what exceptions 2 and 4 should be in reference to and then use the correct terms. My goal for this proposal is only to make what applications are agreeable, to be easy for everyone to come to the same conclusion. So I want to get as much consensus of the agreed applications BEFORE I start crafting better presentation of the language.

This 3 minute video is what prompted this. I am trying to teach this subject so it makes sense to people, but I find the "words in the book" aren't completely making sense. I welcome disagreement and critical thinking. Thank you in advance.

 

[Inspector Gift]

Glen, you provide a nice presentation. Have you looked at what Oregon has done with Townhouses, particularly with options for common two-hour walls? If not, check it out.

 

[Glenn]

Glen, you provide a nice presentation. Have you looked at what Oregon has done with Townhouses, particularly with options for common two-hour walls? If not, check it out.

Thank you. I will check it out.

 

[jar546]

OK, I can see where this section needs a little TLC with the way it is written. With that said, since they made changes in the exceptions from 2018 to 2021 and did not include a double wall in any of the exceptions, I don't believe it is prudent to assume that method should be included. I believe it was intentionally left out. I would hope there is a transcript from the discussions on this section.

 

[Glenn]

OK, I can see where this section needs a little TLC with the way it is written. With that said, since they made changes in the exceptions from 2018 to 2021 and did not include a double wall in any of the exceptions, I don't believe it is prudent to assume that method should be included. I believe it was intentionally left out. I would hope there is a transcript from the discussions on this section.

That's not how the process works. An entire section isn't put up for discussion by any "they". "They" is you and me, my friend. A proposal was made to add a 6th exception to eliminate the independence when sprinklered. The 5th exception was changed to address the new term townhouse units. That's it. What I am asking about was not discussed. That's why I'm asking about it here. To prepare a proposal that will then prompt the discussion for next time.

This thread is not about a call being made in application. We need not be prudent. This discussion is about free opinions about what the intent should be, so I can best craft the words to apply. That's why it's in the code development section. If there is an exception allowing siding, stucco, shingles and any other roof or wall covering to lap over either type of wall, I would like to have a discussion about whether roof flashing and sheathing also can. I want YOU to tell me what YOU think, not what YOU think the CODE thinks. I'm only using all caps for emphasis.