Ending single family zoning in Minneapolis resulted in something to the tune of 100 permitted duplex projects.

https://www.washingtonpost.com/business/what-happened-when-m...

> Minneapolis had 425,336 residents as of mid-2021, the Census Bureau estimates, and 199,143 housing units as of April 2020. By my count the end of single-family zoning has so far allowed for the permitting of at most 97 new units (the above table shows numbers of buildings, not units), some of which haven’t been built yet. If things continue at this pace, ending single-family zoning will have increased the city’s housing supply by just 1% by 2040.

Minneapolis did not change the zoning sufficiently -- the new duplexes and triplexes nearly have to fit into the same footprint as the equivalent single family home. So you can have one big SFH or two half-sized duplexes, etc.

For a single family home, the footprint can't take up more than 50% of the lot. For a duplex, the footprint can't take up more than 60% of the lot. Duplex and triplex projects could be made much more compelling by loosening these restrictions.

https://minneapolis2040.com/media/1816/built-form-districts-...

That's depressing. I can imagine the same thing happening in California because people will think of every other reason they can to stop you.

I'm not trying to be sarcastic or snarky here: is this a serious suggestion that one hundred duplexes (net gain of about 100 housing units I would imagine) is a significant change? Or is there a unit error here?

The number (100 units) is very low. 1% of housing stock is still meaningful in the context of places like Boston where we don't build much at all relative to the metro size.

>> It's not like suburbia is going to line up in droves to have their house converted into a duplex.

That's just not true! People would do that in the neighborhood I live in now in Los Angeles if they could because it would allow you to make the same piece of real estate about 1.5x times as valuable.

More interestingly, in Piedmont California where I grew up, there is a lot of controversy about this. That's an area that is very desirable -- great schools, pretty, close to San Francisco -- but also really expensive. Because its been a nice area for a long time many houses are on huge lots or even have servant's houses (!) that can be built up into a pretty nice house. Of course a lot of the neighborhood hates the idea of converting a single family lot into two homes even under these posh circumstances. But the economic incentives are powerful. I see it happening on my parent very fancy street.

PS: One of the things that really bugs me (in my neighborhood and where I grew up) is when home owners argue about preserving the local character. I grew up in city where my mom and grandmother grew up. The house I grew up in was an adjacent piece of land that once had a single house. Now the neighbors would freak out if you took these large plots of land and built two houses on them or god forbid a duplex. But the truth is they haven't lived their that long and if they did they would know that the neighborhood has always been changing. I wish they could make peace with that.

The duplexes near me sell for less than the SFHs one street over. It's a bit of a worst-of-both-worlds, it seems, compared to either owning a 4+ unit building or a standalone house.

One will see if the backyard ADU end up in a similar situation over time or if the larger "main unit" gives them more value. With duplexes where both units are rentals, there's also probably a bit of a "neither of these are receiving significant owner upgrades" factor compared to an owner-occupied home.

> I really don't see how this would solve anything. It'd allow existing areas of SFH to be slowly converted into duplexes.

Twice as much housing is a lot more housing.

But it isn't. You think all those SFH lots are just going overnight become a duplex? Why would the retired lady who walks her dogs and tends the garden care about building a duplex?

Now when her kids inherit the home & sell it to a developer, sure it'll happen then. But that is a slow, generational process.

Yeah exactly, it's a nice slow process that wouldn't piss people off by having too much rapid change.

I think the point is that it's far too slow to ever make a difference. Is there an existing city which has ever successfully "graduated" through all these levels?

I think you need to meet some of the NIMBYs where I live.

Yeah I'd be curious to know more about how they envision that slow conversion playing out. I don't love all the 30 or 40-story condo buildings that have been built a few blocks away from me in Williamsburg over the past 10-15 years, but people do need places to live in NYC. To really get the density bump in their conversion formula we'd have to demolish avenues of buildings. It's unlikely we can just convert large swaths of three story townhouses to, say, six story buildings like you see in Paris. So we end up with new 40-story buildings in places that were formally zoned for industrial.

I mean, I'm all for trying it, but we probably should have done it 30 years ago since the rent is too damn high now.

Moving the baseline like this would certainly help. It's also helpful to think about areas that are already a little denser than SFH. Replacing duplexes with small apartment buildings and medium apartment buildings with high-rises would have a much bigger impact and this proposal would make that possible as well.

The part I wonder about are provisions for mixed use. At some point some business should be allowed. I think Japanese zoning has a linear system that covers this: https://www.rahulshankar.com/zoning-in-japan/

Problems have solutions, predicaments have outcomes. SF has put themselves into a predicament.

The Strong Towns approach is not really a solution for SF -- it's an approach to prevent the predicament from forming in the first place. Cities that are on the verge of becoming the next SF (Seattle, Portland, Austin) should take heed.