What's the deal with "missing middle" housing?

[Steely Dan]

Originally Posted by eschaton

I feel like the logical cutoff for missing middle is 6 units, which gets you small-scale purpose built multifamily like double triple deckers in Boston, Chicago Six-flats, etc. Too bad the Census doesn't count that.

I use 9 units as the upper cut-off, because 10 units is where all the rules change for MFH in Chicago (sprinklers, elevators, ADA, affordable reqs, etc.), such that a chicago 8-flat shares way more DNA with a bog-standard 3-flat than it does with a large apartment building.

The CB also tracks 5-9 unit buildings independently, so that's convenient.

That cut-off might not work so cleanly in other cities.

[mhays]

To me, missing middle is about unit type, not the number of units. If there are 20 or 30 townhouses in a solid row, that's still missing middle.

[Six Corners]

Originally Posted by iheartthed

I know it's a consolidated city-county. I don't think that matters to the overall point that there is a lot more underutilized land within Nashville's borders than there exists within Chicago's borders.

True. There is some underutilized land. My point though is that there is a lot of difficult land to develop within its boundaries as a city-county due to the hilly terrain, which generally isn't the case in non-city-counties. So Nashville's population density makes it appear that they have more land available to develop than they do. So, it wouldn't hurt to add more missing middle housing to facilitate growth because land for outward expansion isn't as abundant as it would seem.

[eschaton]

Originally Posted by mhays

To me, missing middle is about unit type, not the number of units. If there are 20 or 30 townhouses in a solid row, that's still missing middle.

I still don't get this. 20-30 townhouses are just 20-30 homes, particularly because they're generally built for sale, and not as rentals.

What does it matter whether they share party walls or if they have a few feet between them? If the lot is a certain width, then you're only fitting so many units per block.

Again though, these are not "missing" which is my problem. I agree they're moderate density, but they're the only kind of moderate density built in most metropolitan areas, so they aren't missing in the way that say new-build multi-flats where each floor is a seperate unit are.

[mhays]

In my opinion (opinions obvously differ), the number of units is less relevant than type.

For example two houses on 1/3 of an acre will just be typical SFR development, not missing middle.

[Steely Dan]

Originally Posted by iheartthed

Detroit had 120,706 units in 2-unit structures in 1940, but only 21,214 as of the 2024 ACS data -- an 83% drop. By comparison, Detroit only has 17% more single-family, detached units in 2024 than it had in 1940.

That is one staggering loss.

And it's a big part of the reason why Detroit is now one of the most detached SFH- dominated big cities in the country, even if the raw number of them has only increased by 17% since 1940.

[benp]

Originally Posted by Steely Dan

That is one staggering loss.

And it's a big part of the reason why Detroit is now one of the most detached SFH- dominated big cities in the country, even if the raw number of them has only increased by 17% since 1940.

Great Lakes Cities compared changes in home types between 1950 (peak city population) and 2024:

Chicago//Detroit//Cleveland//Buffalo

Total units: +15.7%//-37.9%//-24.6%//-18.4%

Single detached: +72.2%//-11.5%//+14.3%//+14.1%

Single attached: +390.6%//+490.3%//+1110.5%//+192.4%

2 Unit: -33.2%//-84.4%//-66.9%//-42.8%

3/4 Unit: -14.8%//-83.3%//-77.8%//-51.3%

5+ Unit: +26.6%//-21.5%//-1.0%//+61.5%

It looks like all cities lost 2 to 4 unit homes since 1950.

Between 1950 and 2024, counting both attached and detached totals, Detroit actually has -2.8% fewer single family homes.

[jmecklenborg]

Originally Posted by eschaton

I feel like the logical cutoff for missing middle is 6 units

The FHA defines it as 2-4 units. Above that and you need a commercial loan, which is a completely different animal than a conventional mortgage or FHA loan.

The reason why you see a lot of variety in the older cities is because there was a variety in both lot sizes and in banks. Banking was local and so local banks defined what was possible, not zoning. Since the 1930s the FHA entered the mortgage market and created the cutoff between 4 and 5 units. Now the banks are multi-state and all are essentially the same so there is little variation in the type of loan you can get. You could in theory get an eccentric project privately financed but who is going to throw their money away on somebody wanting to build a 5-unit?

And Minneapolis changed their zoning back in 2020 to allow triplexes on all SFH lots and almost zero have been built to date. Cue the Price Is Right loser horn. I just googled it and there is no new data since 2023. Nobody is tracking the lack of triplex construction in Minneapolis because it doesn't fit the narrative that zoning has been holding back small multifamilies.

[Steely Dan]

Chicago has extremely little variation in R lot sizes; it might be the least varied in the world.

Chicago builders have no problem getting bank loans to construct 2-9 unit buildings.

Chicago's zoning & building codes basically SCREAM at you to build flats on any R lot above R-3.

Chicago still builds so much of this stuff because it very explicitly and intentionally wills it into existence.

Chicago never stopped building missing middle, so there's absolutely nothing it needs to relearn.

[craigs]

L.A. has more than 20,000 vacant lots. They could help solve the city’s housing crisis



Grace Toohey
Los Angeles Times
August 7, 2026

It is perhaps one of the biggest contradictions of Los Angeles’ housing crisis. How can a city where homes are in such short supply and financially out of reach for so many have more than 20,000 lots that are zoned for housing but remain vacant? It’s been a long-missed opportunity, but one that some housing experts hope could now create a fresh wave of attainable homeownership.

A newly launched novel experiment aims to demonstrate how these vacant lots, while small, can be transformed into thoughtfully designed “gentle density” housing — such as duplexes, fourplexes and townhome communities — to be sold at more reasonable prices than L.A.’s long-venerated single-family home. “There hasn’t been a new generation of starter homes since post WWII. How do we get back to that?” said Dana Cuff, director of UCLA’s cityLAB, which is spearheading this phase of the “Small Lots, Big Impacts” initiative, focused on turning vacant, privately owned parcels into affordable homeownership opportunities.
. . . .
Until recently, almost three-quarters of the city’s residential areas were zoned only for single-family homes. But with recent legislation that upended zoning laws across the state, many more lots — including vacant ones — are now open for development of small-scale complexes, each of which can be sold individually. This, proponents say, presents an opportunity to develop reasonably priced homes for sale, particularly in communities that may not have many mid-density buildings.
. . . .
------
Of note: The initiative will include low-interest construction loans from a consortium that includes a public-private entity, the City of LA, and BMO Bank.

[eschaton]

Originally Posted by mhays

In my opinion (opinions obvously differ), the number of units is less relevant than type.

For example two houses on 1/3 of an acre will just be typical SFR development, not missing middle.

I'm not sure what your point is here. Two houses on 1/3rd of an acre is a huge yard, by urban standards.

My house is a six bedroom Victorian. The lot is 34 by 100, which is what - less than 1/12th of an acre?

I do agree that you can get a lot more density with townhouses. Hell, across the street there's a parcel not much larger than mine with five townhouses on it. But you can find small detached homes in Pittsburgh on lots with less than 20 feet of street frontage (sometimes like 16-18). Often the lots are subdivided in the rear, so instead of being 100 feet, they're more like 50. So you can still have quite a good deal of residential density.

Originally Posted by jmecklenborg

The FHA defines it as 2-4 units. Above that and you need a commercial loan, which is a completely different animal than a conventional mortgage or FHA loan.

The reason why you see a lot of variety in the older cities is because there was a variety in both lot sizes and in banks. Banking was local and so local banks defined what was possible, not zoning. Since the 1930s the FHA entered the mortgage market and created the cutoff between 4 and 5 units. Now the banks are multi-state and all are essentially the same so there is little variation in the type of loan you can get. You could in theory get an eccentric project privately financed but who is going to throw their money away on somebody wanting to build a 5-unit?

I understand that there's a funding cutoff there. However, if you're comparing building typologies, a six-unit building is very similar to a 3-4 unit, yet very different from larger buildings, which are simply small apartments.

That is to say, if you look at the prewar building typologies, you often saw some variation of the following:

1. A two-unit where each took up an entire floor of a two-story building.

2. A three-unit where each took up an entire floor of a three-story building.

3. Four-units where you just semi-attach two two-units to one another.

4. Six units, where two three-units are smushed together.

To the best of my knowledge, there is no standard type of middle-density housing with five units. I guess it might happen from time to time. But when you get to 7+ units, you're basically just in walkup apartment territory. Very unlikely to be a chopped-up home either, unless it was a truly enormous mansion.

[Steely Dan]

Originally Posted by craigs

L.A. has more than 20,000 vacant lots. They could help solve the city’s housing crisis

LA has 20,000 vacant lots???

Never would've guessed that.


Chicago is estimated to have 30,000 vacant R lots. I would have thought that LA's total would have been closer to 5 or 10% of Chicago's, not 2/3!

I mean, LA doesn't have any rustbelt-style urban prairies anywhere. Where are these 20,000 vacant lots?

[Steely Dan]

Originally Posted by eschaton

To the best of my knowledge, there is no standard type of middle-density housing with five units. I guess it might happen from time to time. But when you get to 7+ units, you're basically just in walkup apartment territory.

In Chicago, 5 units is pretty damn rare, but we've done a few of them on irregular lots when that's how the math has shaken out. It usually involves duplexing 2 units down into the basement, front and back, with the other 3 units above being full floor.

7 units is even rarer still, but 8 units is fairly standard- just two 4-flats smushed together, not unlike a 6-flat being two 3-flats smushed together. I've personally drawn about ten 8-flats at my current job. 8-flats are certainly not the most common unit count, but they're not exactly unicorns either, like 5 or 7 units..



Contrary to a certain other voice in this thread, in Chicago it's ALL about the underlying zoning, and what can be built as of right according to the zoning math. Banks here will finance whatever the zoning allows. Let's hope America can catch up.

[craigs]

Originally Posted by Steely Dan

LA has 20,000 vacant lots???

Never would've guessed that.

Chicago is estimated to have 30,000 vacant R lots. I would have thought that LA's total would have been closer to 5 or 10% of Chicago's, not 2/3!

I mean, LA doesn't have any rustbelt-style urban prairies anywhere. Where are these 20,000 vacant lots?

Yeah, I was surprised as well. The article stated that those 20,000 lots constitute 2% of all privately-owned parcels in the city. I assume they are scattered around, because as you noted, there aren't any rustbelt-style urban prairies even in the worst parts of town.

I assume that owners generally want to build, but zoning (until recently) precluded projects that pencil out. The recent changes at the state level allow for middle-density projects in areas that previously barred them. Three groups have been approved for the first loans, and they have differing plans for the size and layout of the new builds. Presumably, they could all become prototypes for new missing-middle housing.

Anecdotally, I can't think of any vacant lots in my current neighborhood, but a Westside building I lived in back in the '90s is now a vacant lot. The landlord owned three adjacent properties and was waiting for everyone to move out of all three before she developed them into a big complex. Now, two of the three have been torn down, and the third appears to be boarded up. It's been that way for several years now, though, so she (or, perhaps, her heir) is just sitting on a gold mine. That area is already zoned for high-density multifamily.

[iheartthed]

Originally Posted by Steely Dan

LA has 20,000 vacant lots???

Never would've guessed that.


Chicago is estimated to have 30,000 vacant R lots. I would have thought that LA's total would have been closer to 5 or 10% of Chicago's, not 2/3!

I mean, LA doesn't have any rustbelt-style urban prairies anywhere. Where are these 20,000 vacant lots?

If those estimates are close to accurate then Chicago has a far higher rate of vacant lots per square mile than Los Angeles. Chicago's average vacant lot per square mile would be 132 compared to Los Angeles's 43, or in other words Chicago's vacant lots per square mile rate is 3x Los Angeles's.

[Steely Dan]

Originally Posted by iheartthed

If those estimates are close to accurate then Chicago has a far higher rate of vacant lots per square mile than Los Angeles. Chicago's average vacant lot per square mile would be 132 compared to Los Angeles's 43, or in other words Chicago's vacant lots per square mile rate is 3x Los Angeles's.

And I would've expected Chicago's rate to be 10x, or even 20x.

LA straight-up doesn't have urban prairies like the rustbelt cities.

There is absolutely nothing like Chicago's Englewood CA anywhere in LA.

Something seems off here.

[craigs]

Originally Posted by iheartthed

If those estimates are close to accurate then Chicago has a far higher rate of vacant lots per square mile than Los Angeles. Chicago's average vacant lot per square mile would be 132 compared to Los Angeles's 43, or in other words Chicago's vacant lots per square mile rate is 3x Los Angeles's.

I would imagine that Chicago's vacant lots are geographically concentrated, too, so they might be more noticeable if one is in such an area. I had never even considered how many vacant lots there are in LA until I saw the article, because (as best I can tell), they are randomly scattered about the city.

[iheartthed]

Originally Posted by Steely Dan

And I would've expected Chicago's rate to be 10x, or even 20x.

LA straight-up doesn't have urban prairies like the rustbelt cities.

Something seems off here.

Oh. I would not have expected that. I might expect that comparing L.A. vs Detroit, but not L.A. versus Chicago. Chicago is quite a bit more densely populated than Los Angeles.

[craigs]

Originally Posted by Steely Dan

And I would've expected Chicago's rate to be 10x, or even 20x.

LA straight-up doesn't have urban prairies like the rustbelt cities.

There is absolutely nothing like Chicago's Englewood CA anywhere in LA.

Something seems off here.

If the article is correct, then there are about 1,000,000 privately-owned residential properties in Los Angeles, and 2% of them are currently vacant lots. That is a pretty low percentage, which accounts for why we don't perceive the city as having a lot of vacant lots. I don't know Chicago well enough to estimate the percentage of privately-owned residential properties that are currently vacant lots.

[Steely Dan]

Originally Posted by craigs

I don't know Chicago well enough to estimate the percentage of privately-owned residential properties that are currently vacant lots.

Google says Chicago has ~30,000 vacant lots, with ~10,000 of them city-owned, and ~20,000 of them privately owned.