A short point about why eliminating single family zoning won't result in a rise in "affordable housing" (any time soon)

I've already written about this, in response to initial coverage about how Minneapolis is setting the stage to eliminate single family zoning, to increase the opportunity for more housing in what are now single family residential zones.

But the New York Times just ran another article ("Cities Start to Question an American Ideal: A House With a Yard on Every Lot") along with an editorial ("A City's Bold Housing Plan").

The NYT article shows images of various cities, and how much of the land is zoned single family.  For the DC graphic, blue is rowhouse and multiunit, red is single family.

1.  First, while seemingly a huge change in policy it's not really enough to lead to substantive change, in that you need a broader range of housing types, beyond even duplexes and triplexes.  You need smaller apartment buildings, plexes of various sorts (e.g., housing types in Cleveland, Boston, Montreal) along with even larger buildings.

But this could seriously change neighborhood character, so it has to be planned.

End unit new construction rowhouse on 5th Street NW in Petworth.



2.  More importantly, it will take decades.  Because individual property owners lack the capital and motivation to do this on their own.

So it will only come about as properties come on the market and are sold to flippers who will do the conversion.  And assembling multiple lots is probably beyond the desire for quick return, meaning that smaller apartment buildings won't ever get developed.

3.  And potential owners have to be willing to live in a shared building.

4.  And the financial system, in particular mortgage finance companies, have to be willing to fund mortgages of such properties.

5.  But at the same time, the new housing units won't be affordable, because it's constructed at today's prices for land, labor, and materials, and profit.

We have a "natural experiment" for this in what were called R4 districts in DC (I don't know the new categorization), which are rowhouse districts.  Rowhouse properties comprise much of the city's core

It is legal to divide them into two dwellings without special zoning review.  (Although I argue that larger buildings ought to be allowed to become more than two units, if appropriate.)

What firms are doing is buying rowhouses and adding a floor and digging out the basement to make two bigger units.

Such as this property on 13th Street NW in Columbia Heights.


Each unit is being marketed "in the $800,000s".

That's not affordable.  But it does add a unit of housing.

6.  You still need market demand to drive small property developers to do this.  When the tv show "Rehab Addict" used to feature house rehabilitations in Minneapolis, I was surprised at how cheap the houses were--sometimes as little as $1, when bought from the city.

Granted it will be cheaper to buy the property and do the rehab in a weaker real estate market.

But at the end of the day someone still has to be willing to buy the property.

7.  And to get a mortgage the property will need to be able to be appraised high enough to get a mortgage, which is hard when you can buy single family units for less than the cost of a rehabilitated now half of a duplex.

In weak real estate markets like Minneapolis or Baltimore, you don't have the pricing premium necessary to drive such property development.

You need serious subsidy.

In Seattle or DC it's a different story.