Urban Math: the multiplying power of small scale multi-family

[Steely Dan]

i live on a block with 40 chicago-size lots (20 lots on either side of the street, anywhere from 25' - 30' wide x 125' deep).

it was built-out a century ago primarily with 2-flats, some 3 flats, and larger 12-unit buildings on all 4 corner double-lots. 6 of the 2-flats have since been de-converted to SFHs.

if my street were entirely SFH, it'd only have 40 housing units, but being a mixture of a few SFH and mainly small scale multi-family, we have a total of 106 housing units on our block, a 2.6x unit density increase.

my census tract, as it exists today, is ~26,000 ppsm, but were it 100% SFH like so much of our nation, the density would fall to only ~10,000 ppsm.

and nothing on my block stands taller than 3 floors, so it still has the scale and feel of a low-rise family-friendly neighborhood side-street, just with a lot more people living on it.

this site obviously spends a lot of time talking about the density-add of highrises, midrises, and other large-scale urban buildings, but if we could find a way to shoe-horn just an extra unit or two onto every single city lot, and do so across dozens and dozens of square miles, it really would add up to a significant difference all by itself, no highrises required.

[jmecklenborg]

A 3-bedroom house can have more residents than a building with four one-bedroom units.

This Twitter war against single-family houses is a Two Minutes of Hate. The owner-occupied single-family house is the most flexible type of housing, as family members and less often friends can come and go without formal leases.

No professionally managed rental allows girlfriends/boyfriends, relatives, etc., come and go without a lease.

[Steely Dan]

Originally Posted by jmecklenborg

A 3-bedroom house can have more residents than a building with four one-bedroom units.

"can" and "does" are two different things.

anyway, the overwhelming majority of flats on our street are 1,000 - 1,500 SF w/ 2 - 3 bedrooms, with some 1 bed/studios in the larger corner apartment buildings.

and of course we also have a handful of 4, or even 5 bed deconverted 2-flats for the rich people.

Originally Posted by jmecklenborg

This Twitter war against single-family houses is a Two Minutes of Hate. The owner-occupied single-family house is the most flexible type of housing, as family members and less often friends can come and go without formal leases.

i have absolutely no idea what this twitter war you speak of is (i've never been on twitter).

there's no stupid "war" here or whatever, i'm strictly talking about the density multiplier effect of small-scale multi-family hosuing.

99 times outta 100, a street with 106 housing units spread across chicago-style flats (almost always 2+ beds) is gonna house more people than the same exact street with 40 detached SFH bungalows.

and the stats bear it out. my CT has a pop. density of 26,000 ppsm.

CHALLENGE: find a CT made up of >90% detcahed SFHs that's north of 25K ppsm.

Originally Posted by jmecklenborg

No professionally managed rental allows.......

that's another beauty of small scale multi-family.

the vast majority of buildings on my block are not "professionally managed".

the owner lives in one unit and rents out the other unit(s), others are fully-condo'ed (like our 3-flat), or in a few cases, one-off investor owners.

[Crawford]

Originally Posted by Steely Dan

CHALLENGE: find a CT made up of >90% detcahed SFHs that's north of 25K ppsm.

Maybe a poor Latino neighborhood in LA? It would be sorta cheating, though, in that a huge share of the units, while legal SFH, would be occupied by multiple families.

I thought about Queens, too, but most of the pure SFH Queens neighborhoods are pretty rich, so not likely to have illegal housing situations. And there really aren't too many 90%+ SFH areas in NYC outside of south shore of Staten Island (which wouldn't hit 25k psm).

[Steely Dan]

Originally Posted by Crawford

Maybe a poor Latino neighborhood in LA? It would be sorta cheating, though, in that a huge share of the units, while legal SFH, would be occupied by multiple families.

good call. an LA detached SFH neighborhood with each house packed to the gills with large multi-generational immigrant families might be able to do it.

(and even then, i suspect there's a main drag somehwere in the CT full of dingbats or other such multi-family buildings that drags the overall detached SFH unit percentage below 90%)


but we all know that's not the way native-born middle-class americans tend to live anyway.

Originally Posted by Crawford

I thought about Queens, too, but most of the pure SFH Queens neighborhoods are pretty rich, so not likely to have illegal housing situations. And there really aren't too many 90%+ SFH areas in NYC outside of south shore of Staten Island (which wouldn't hit 25k psm).

to keep the comparison intra-city for the sake of consistency, i looked at the CT that one of my best friends lives in out on the far NW side of chicago. he's out in jeff park, and his block has 20 city lots on either side of it, just like mine, except his street is 100% tidy little bungalows, just like all of the other streets in his CT, excpet for the main drag along higgins ave. which does have a fair amount of multi-family buildings. even out in hard-core bungalow belt areas of chicago, there's always at least one street or area that multi-family buildings coalesce around.

the density of his "bunaglow belt" CT is 11K ppsm

the density of my "missing middle" CT is 26K ppsm


that extra 15K ppsm might not sound like an earth-shattering difference, but if you spent and afternoon walking around our two neighborhoods, you'd soon realize how much greater the density of shit to actually walk to is in my neighborhood compared to his.

[JManc]

Originally Posted by jmecklenborg

A 3-bedroom house can have more residents than a building with four one-bedroom units.

But most quadplexes typically aren't one-bedrooms though. A lot of the Chicago style flats, for example, are typically 2-3 bedroom.

[jmecklenborg]

Originally Posted by JManc

But most quadplexes typically aren't one-bedrooms though. A lot of the Chicago style flats, for example, are typically 2-3 bedroom.

I don't know the percentage but in my area there are tons of 1-bedroom 4-plexes. Like thousands of them. They were selling for $100k ($25k per unit) during the recession ten years ago.

These:
https://www.google.com/maps/@39.1492...7i16384!8i8192

[Steely Dan]

Originally Posted by jmecklenborg

I don't know the percentage but in my area there are tons of 1-bedroom 4-plexes. Like thousands of them. They were selling for $100k ($25k per unit) during the recession ten years ago.

These:
https://www.google.com/maps/@39.1492...7i16384!8i8192

neat.

so let's use mhays' "rule of thumb" math here:

four 1-bed multi-family units x 1.5 avg. household size = 6 people

one detached SFH x 2.5 avg. household size = 2.5 people

[mhays]

Originally Posted by jmecklenborg

A 3-bedroom house can have more residents than a building with four one-bedroom units.

This Twitter war against single-family houses is a Two Minutes of Hate. The owner-occupied single-family house is the most flexible type of housing, as family members and less often friends can come and go without formal leases.

No professionally managed rental allows girlfriends/boyfriends, relatives, etc., come and go without a lease.

Yet most houses have fairly few people. In my city the rule of thumb is about 1.5 per multifamily unit and 2.5 per house. The national average for houses is a little higher than that iirc, but not massively so.

And yes, tons of apartments have roommates, girlfriends, etc. Condos obviously as well.

[Klippenstein]

Originally Posted by mhays

Yet most houses have fairly few people. In my city the rule of thumb is about 1.5 per multifamily unit and 2.5 per house. The national average for houses is a little higher than that iirc, but not massively so.

And yes, tons of apartments have roommates, girlfriends, etc. Condos obviously as well.

Multi family unit includes all sizes of units right? I bet if those numbers are adjusted for size that the multi family units would probably end up housing more people per same area (size of the dwelling). I’d be curious to see if that’s true.

[mhays]

Originally Posted by Klippenstein

Multi family unit includes all sizes of units right? I bet if those numbers are adjusted for size that the multi family units would probably end up housing more people per same area (size of the dwelling). I’d be curious to see if that’s true.

Probably!

In the Seattle area, multifamily is often of the one-bedroom variety, which pushes the average down.

It's one-bedrooms because new apartments are mostly in commercial areas, and because our land use codes favor thicker buildings that encourage shoebox-shaped units.

[Steely Dan]

Originally Posted by mhays

In my city the rule of thumb is about 1.5 per multifamily unit and 2.5 per house. .

and for the specific type of "missing middle" small-scale multi-family housing I'm talking about like chicago-style flats, i'd hazard a guess that a decent "rule of thumb" average household size would be much closer to 2.0 than 1.5.

as mentioned earlier in the thread, this style of multi-family housing unit is far more likely to have actual families with children living in it than units in a typical apartment block because they tend to be larger, typically with 1,000 - 1,500 SF and 2 or 3 bedrooms, and with small shared outside yard spaces in the front and/or back (a significant consideration for those raising children).


take the 3-flat we live in for example: the 2 upstairs units are each 1,300 SF | 3 bed/2 bath, and the 1st floor/basement 2-floor unit is 2,300 SF | 3bed/3bath. all together, there are 9 people who call the building home (6 adults and 3 children). now, if our 3-flat were replaced by a bog standard chicago bungalow with 3 or 4 bedrooms, you might conceivably have a larger family in there with 5 or 6 people living in it (though in my experience, families that large are exceedingly rare in the city outside of certain immigrant communities), but with an overall city-wide average hosuehold size of 2.45 in chicago, you generally aren't getting anywhere close to 9 people living in that bungalow, outside of some real outlier cases.

[Investing In Chicago]

Originally Posted by Steely Dan

and for the specific type of "missing middle" small-scale multi-family housing I'm talking about like chicago-style flats, i'd hazard a guess that a decent "rule of thumb" average household size would be much closer to 2.0 than 1.5.

as mentioned earlier in the thread, this style of multi-family housing unit is far more likely to have actual families with children living in it than units in a typical apartment block because they tend to be larger, typically with 1,000 - 1,500 SF and 2 or 3 bedrooms, and with small shared outside yard spaces in the front and/or back (a significant consideration for those raising children).


take the 3-flat we live in for example: the 2 upstairs units are each 1,300 SF | 3 bed/2 bath, and the 1st floor/basement 2-floor unit is 2,300 SF | 3bed/3bath. all together, there are 9 people who call the building home (6 adults and 3 children). now, if our 3-flat were replaced by a bog standard chicago bungalow with 3 or 4 bedrooms, you might conceivably have a larger family in there with 5 or 6 people living in it (though in my experience, families that large are exceedingly rare in the city outside of certain immigrant communities), but with an overall city-wide average hosuehold size of 2.45 in chicago, you generally aren't getting anywhere close to 9 people living in that bungalow, outside of some real outlier cases.

This is what makes Chicago the best livable city in the Country in my opinion. Virtually the entire city was designed to house families in actual liveable conditions with outdoor space.

My Lakeview Neighborhood looked very similar to the Lincoln Square streets you shared , a mix of 2 unit, 3 unit, 6 unit, and SFH's blended together.
What I like about my particular neighborhood, is that if you want a block that is almost exclusively SFH, you can have that, if you want a block that is all multi family, you can have that too.

This is about 1 block from where I lived, these Greystones have almost all been converted to SFH, but still keep the character of the neighborhood:

https://www.google.com/maps/place/37...!4d-87.6613871

While this block is almost exclusively multi family, yet looks similar:

https://www.google.com/maps/@41.9486...7i16384!8i8192

This block is heavy newer construction SFH's, yet doesn't feel all that different:

https://www.google.com/maps/@41.9486...7i16384!8i8192

These 3 blocks are all within a stones throw of one another and probably have a blended density in the 25K range, which is perfect, IMO. It is able to support multiple thriving commercial districts, the main one here being Southport Ave. Though Wrigley Field being close by certainly helps the business' as well.

[Steely Dan]

Originally Posted by Investing In Chicago

These 3 blocks are all within a stones throw of one another and probably have a blended density in the 25K range, which is perfect, IMO.

yep, the density of that CT is ~28.5K ppsm.

[Chef]

Originally Posted by Steely Dan

i live on a block with 40 chicago-size lots (20 lots on either side of the street, anywhere from 25' - 30' wide x 125' deep).

it was built-out a century ago primarily with 2-flats, some 3 flats, and larger 12-unit buildings on all 4 corner double-lots. 6 of the 2-flats have since been de-converted to SFHs.

if my street were entirely SFH, it'd only have 40 housing units, but being a mixture of a few SFH and mainly small scale multi-family, we have a total of 106 housing units on our block, a 2.6x unit density increase.

my census tract, as it exists today, is ~26,000 ppsm, but were it 100% SFH like so much of our nation, the density would fall to only ~10,000 ppsm.

and nothing on my block stands taller than 3 floors, so it still has the scale and feel of a low-rise family-friendly neighborhood side-street, just with a lot more people living on it.

this site obviously spends a lot of time talking about the density-add of highrises, midrises, and other large-scale urban buildings, but if we could find a way to shoe-horn just an extra unit or two onto every single city lot, and do so across dozens and dozens of square miles, it really would add up to a significant difference all by itself, no highrises required.

This is why Minneapolis has neighborhoods that are 50% single family homes, but are close to 20,000 ppsm and have higher density than rowhouse neighborhoods. If you drop three or four 20 unit apartment buildings and a couple duplexes on a block of streetcar suburbia you have tripled or quadrupled its density.

[jd3189]

We need to start doing more of this, especially in most of American suburbia. It seems to be the best of both worlds and can be the foundation of having more walkable suburbs.

[Crawford]

Given that most SFH neighborhoods have rules against non-family units living together, not sure how it can be the "most flexible" housing model. Generally seems like the worst housing model. We have a nation where the vast majority of households aren't married couples with children, and the share of married couples with children is plummeting, yet newer SFH are almost 100% geared to that demographic. The average new construction SFH has 4+ bedrooms and is nearing 3,000 sq. ft. So useless to the vast majority of households.

[mhays]

In a city as cold as Chicago (and even in mild Seattle) I'll take a condo where my front door opens to a hallway. Also, nobody knocks on the door, EVER.

That said, since most people aren't me, we badly need more missing middle housing in Seattle. Both Seattle and Bellevue will upzone wide areas in 2024, and are currently studying options for whether to focus these into dense nodes (like the current plans do) or also allow more missing-middle types like fourplexes in current single-family areas. Bellevue is debating whether to plan for 35,000 or 70,000 more housing units from 2024-44 and Seattle anticipates 100,000 or 120,000 more in the same period. Tacoma is ahead of us, already updating its codes for another 45,000 including middle-middle in single-family zones. Seattle allows two small accessory units on most house lots but not family-sized units.

[Steely Dan]

Originally Posted by mhays

In a city as cold as Chicago (and even in mild Seattle) I'll take a condo where my front door opens to a hallway. Also, nobody knocks on the door, EVER.

the overwhelming majority of chicago flat buildings (like >95%), have interior front staircases, so your unit's front door would open onto the stair hall, not directly to the exterior.

for the back stair, they are very frequently of the open variety, with attached porches, though sometimes people enclose them for weather protection purposes.


here's our building's back stair, it's obviously "open" style:

[iheartthed]

I'm gonna stir the pot here (), but I hate how Chicago's zoning forces setbacks in so many of its multi-tenant housing zones.