Mo Zhu

Fun fact: The town in Massachusetts where I grew up calls itself "the town of homes" which now triggers me af.

Mo Zhu reposted

Patrick Siegman

@siegman.biz

sfchronicle.comADU ruling could be a boon to California buildersCalifornia local governments must quickly approve legally submitted applications to build accessory dwelling units, a state appeals court ruled in a victory for advocates of more housing.

It looks like California cities that wrongly deny housing will now have to pay serious damages: “Local governments must quickly approve legally submitted applications to build accessory dwelling units…a state appeals court ruled in a victory for advocates of more housing & less governmental review“

Big day on Thursday we have four items on the agenda! Thurs Oct 29 @ 10am ET/1pm PT. G13 "middle housing" working group - Fire study group Here's the link. teams.microsoft.com/meet/2859829...

admin.centerforbuilding.orgadmin.centerforbuilding.org

And finally, #6 IRC expansion. Explained here: bsky.app/profile/moin...

Mo Zhu@moinmybackyard.bsky.social

There is an important pro-affordability code change proposal we'll call "IRC Expansion." It expands the scope of the International Residential Code to 3- and 4-unit buildings. It's a step in the right direction, but I have many mixed feelings about it. 🧵 admin.centerforbuilding.org/wp-content/u...

I'll be live poasting it and participating. Thread to come!

Big day on Thursday we have four items on the agenda! Thurs Oct 29 @ 10am ET/1pm PT. G13 "middle housing" working group - Fire study group Here's the link. teams.microsoft.com/meet/2859829...

#4 @willskud.bsky.social's exterior window size proposal, explained here: bsky.app/profile/moin...

Mo Zhu@moinmybackyard.bsky.social

- On Thurs Oct 29 @ 1pm ET/10am PT, - @willskud.bsky.social of CBNA will present a code change proposal ... - to the ICC's G13 "middle housing" committee's Fire working group. It will increase the allowable size of exterior windows on residential buildings, which is important for dense urban lots.

drive.google.comNFPA 13R type I_II story increase proposal.pdf

#5 @stephenjacobsmith.com's height increase for sprinklered Type I and II construction. Explained here: bsky.app/profile/moin...

Mo Zhu@moinmybackyard.bsky.social

Another sprinkler proposal by the folks at CBNA! This one led by @stephenjacobsmith.com. It would increase the allowed stories of R-2 (multifamily apartments) buildings of Type I construction to 6 stories and Type II construction to 5 stories, up from 4. drive.google.com/file/d/1OyY0...

Big day on Thursday we have four items on the agenda! Thurs Oct 29 @ 10am ET/1pm PT. G13 "middle housing" working group - Fire study group Here's the link. teams.microsoft.com/meet/2859829...

The first two items on the agenda are unrelated to us. #3 we will be reviewing the results of the Minnesota study. We got the presentation last week (see attached thread), but we will hear the folks digest and discuss on this call. bsky.app/profile/moin...

Mo Zhu@moinmybackyard.bsky.social

Carl and Nicholas are the lead presenters. "We were tasked with getting data" and we are not going to present opinions on single stairs.

admin.centerforbuilding.orgadmin.centerforbuilding.org

This proposal is being heard on Thursday Oct 29 at 1pm ET/10am PT. Link and live thread to come!

A piece of my thread seems to have gotten lost... very quickly, back to the 6000 sqft area limitation... I promise this'll be good. bsky.app/profile/moin...

Mo Zhu@moinmybackyard.bsky.social

Silly me, somehow a piece of my thread was lost. Here it is... continuing on the 6000 sqft area limitation. What is the reason for limiting the floor area?

admin.centerforbuilding.orgadmin.centerforbuilding.org

Silly me, somehow a piece of my thread was lost. Here it is... continuing on the 6000 sqft area limitation. What is the reason for limiting the floor area?

It is that "four dwelling units of 1,500 square feet each would be reasonably consistent with affordable housing. Likewise, 6,000 square feet is a reasonable limit for a multifamily building that would not be out of place in a residential neighborhood or infill housing." Purely zoning reasoning!

admin.centerforbuilding.orgadmin.centerforbuilding.org

Finally, this is an optional appendix, so in order to adopt it, it would be jurisdiction-by-jurisdiction effort. I worry that this gives the ICC a free pass on affordability. As I documented in Nashville, they prefer to dig in and wait out the storm.

This appendix then, might be a nice little incremental do-not-much alternative that affordability opponents can use to re/misdirect legislators. I don't think we should let the ICC off the hook this easy!

admin.centerforbuilding.orgadmin.centerforbuilding.org

This requirement is particularly confusing because the proposal itself cites that NFPA 13D sprinklers prevented 87% of fires from spreading to another room and 92% of fires from spreading to another floor.

To protect the new shared corridor, this proposal already requires a sprinkler head at each landing, which seems reasonable. The additional fire sprinkler head does not seem necessary.

admin.centerforbuilding.orgadmin.centerforbuilding.org

www3.iccsafe.orgwww3.iccsafe.org

Now, the IRC expansion adds a new shared hallway between units. How do we handle this? Well, the ICC issued an interpretation which stated that hallways between units in hotels and MFH are also 40 psf. www3.iccsafe.org/cs/committee... This concern does not justify a discretionary veto!

#6 it requires the assumption that the sprinkler system will use 3 sprinklers to control a fire rather than just 2, increasing the cost of the sprinkler system. You need a bigger tank with more capacity and you might need a bigger meter from the utility.

admin.centerforbuilding.orgadmin.centerforbuilding.org

The IRC is supposed to be a "cookbook" with prescriptive rules that "just work." This requirement would violate that principle. The cited reason is structural, but again, the proposal does not increase the height of buildings nor the unit stacking. So there should be no structural concern.

Even if it did increase unit stacking to 3, as I want, the codes already handle for this. Both the IRC and IBC references ASCE 7 for structural live load and both settle on 40psf for apartments. So even for apartments that have three-stacked units, the IBC still uses the same 40psf!

admin.centerforbuilding.orgadmin.centerforbuilding.org

#4 each unit is limited to four bedrooms. Why? "to place a limit on the possible use of these buildings as high-occupant density dormitories." Again, a zoning argument. Worse, it's a social engineering argument, with undertones of redlining.

#5 at the discretion of the building official, s/he may require an engineering stamp. According to one developer, an engineering stamp might be 10-15% the total cost of a 4-unit project! This is potentially a straight-up veto with opportunities for corruption.

admin.centerforbuilding.orgadmin.centerforbuilding.org

...that shows that in 92% of cases, 13D sprinklers prevented fires from spreading to another story. So with that, he concludes that "The limit on stacking of dwelling units is believed to be [passive voice] a reasonable [to whom?] redundancy to protect occupants of upper floors."

#3 a 3-4 unit building in the IRC can only have 3 occupiable stories. Current IRC homes effectively allow a fourth story via a habitable attic. The new 3-4 unit buildings cannot access the habitable attic. Yes, #2 and #3 combined is weird. No triple decker, but 2-story over 1-story is ok.

admin.centerforbuilding.orgadmin.centerforbuilding.org

pew.orgModern Multifamily Buildings Provide the Most Fire ProtectionA large body of research has demonstrated that apartment buildings and other types of multifamily housing can provide many benefits to a community, especially when built in high-demand areas where hou...

This claim ignores the reality that multifamily units are no worse than single family units in terms of fire outcomes. Just ask yourselves: Are Boston triple deckers fiery death holes? www.pew.org/en/research-...

The author then raises the prospect of fires rising upwards as a threat to upstairs residents (this is true for 100 story buildings too). But immediately admits that the sprinklers should prevent that. Elsewhere, he cites data from the National Fire Incident Reporting System (NFIRS)...

admin.centerforbuilding.orgadmin.centerforbuilding.org

#2 there can only be two units stacked on top of each other. This means that the Boston triple decker is not allowed. bsky.app/profile/ille... Why?

This Home Is Illegal@illegalhomes.bsky.social

Over to 24 Seaverns Ave in Jamaica Plain today. It's a classic triple-decker built in 1905, and like 99% of Boston homes, it's illegal under Boston's zoning code.

The author uses two paragraphs to firemonger. More stacked units "significantly increases the risk of injury or death ... for upper unit occupants. The more units below, the higher the likelihood of a fire occurring below… more kitchens, more occupants, more battery powered equipment, etc."

admin.centerforbuilding.orgadmin.centerforbuilding.org

But it comes with a couple big ifs, many of which I find unnecessary on the merits. Moreover, the reasoning for these seem almost designed to infuriate me! (and probably you too) So with that YIMBY trigger warning, let's dive in...

#1 each 3-4 unit building has a max area of 6k sqft (no such limitation for SFH, duplexes, or town homes). The IRC currently allows unlimited floor area. Why punish 3-4 unit buildings? Structural? No, because this proposal doesn't change the allowed height or stacking of units.

admin.centerforbuilding.orgadmin.centerforbuilding.org

This proposal is a response to that external pressure. But as I documented in Nashville, they are not happy about it. bsky.app/profile/moin...

Mo Zhu@moinmybackyard.bsky.social

I am at the ICC conference in Nashville! Unlike last year's conference, affordability was a constant topic. In just half a day, it came up in three separate contexts (two unforced). Sadly, affordability was only seen as a trojan horse for legislative "encroachment" and commercial interests.

This proposal expands the IRC to 3-4 unit dwellings (yay!). It would add the possibility of a shared corridor to the IRC for the first time (rather than each unit opening directly to the exterior) and it would add stricter fire resistance between units (1 hr vs 1/2 hr).

admin.centerforbuilding.orgadmin.centerforbuilding.org

The IRC is the ICC's carveout for the single family homebuilders. It only covers SFH, duplexes, and townhomes, while the IBC covers everything else (eg MFH, sports arenas, factories). The IRC has various features that make it cheaper to build. In the US, SFH is about 25% cheaper to build per sqft.