Popup


 

Time period:2000s to 2015, limited height afterwards
Location: Washington DC

Adding floors (and homes) on top of a rowhouse 

Key features
- Narrow lot
- Reuses lower floors of an existing rowhouse

The rowhouse, a multistory house on its own lot but sharing a wall with its neighbors, is a common type of home in the Mid-Atlantic region. In Philadelphia and Baltimore, rowhouses make up half of all homes. In Washington DC, 1 in 4 homes is a rowhouse.  Elsewhere in the United States, rowhouses make up less than 10%. The classic rowhouse is only one room wide, and has the living room and kitchen on the 1st floor, and two bedrooms on the 2nd floor.

Like other US cities, DC started getting tall buildings in the late 1800s. However, unlike other cities, the US Congress has the power to pass local laws in DC, and in 1899 Congress passed a citywide height limit that banned skyscrapers. In the mid and late 20th century, as number of government workers increased, this height limit meant that the city had to grow outwards. New high-rise suburbs were built around Metro stations such as Silver Spring, Rosslyn, and Crystal City.  

Within the District itself, there were lots of 2-story rowhouses in land that was zoned for mid-rise apartments. Few were redeveloped as it is expensive and time-consuming to buy up several adjacent rowhouses, each with a different owner, to get a large enough site for a regular apartment building. However, by the 2000s, housing demand and prices had gotten so high in DC that even individual lots could be redeveloped at a profit.

Enter the pop-up. There were two varieties - the mansion and the duplex. Mansionization added a floor or two with additional bedrooms, and sometimes a roof deck, turning a small 1,500 square foot two-bedrooom home into a 2,000+ square foot home with 3 or more bedrooms.  Duplexization turned the added space into an additional unit.  

Extreme examples popped up all the way to 5 stories (the limit of wood frame construction) and had three units, stacking a pair of rowhouses above a small first-floor flat.  Built on 1,200 square foot lots, these buildings achieved a density similar to conventional midrise apartments, and were equally controversial. On a block where other houses were only 2 stories, a 5-story popup stuck out like a sore thumb - or sometimes a sore middle finger if it was in the middle of a block.  They also popped out in the back, as an extra stair had to be inserted in the middle to access the upper units, pushing the back rooms into the backyard.

Different types of popups, compared to an original 2-story rowhouse

Pushback against popups led to a change to the zoning laws.  R-4 zoning, which used to be common in wide stretches of the city just outside the downtown core, was heavily downzoned.

The new rules reduced the maximum size and density of buildings:
- No more than 40 feet tall and 3 floors.
- No more than 2 units on a typical lot.
- Building cannot cover more than 60% of the lot. (no more rear extensions)

Today this land is zoned RF.   


Floorplan of a 5-story popup with 3 homes.

Data
- Typical Lot Size: 1,200 square feet (12'x100')- Density: 50-100 units/acre
- Typical Zoning: R-4 midrise multifamily (former), RF-1, RF-2, and RF-3 single family and duplex attached (current)
- Construction Type: V (Wood frame)
- Resident Type: Homeowners with some rentals.

Where to Build
- High-demand areas near downtown where small lots make land assembly for a larger building difficult.
- Taller popups aren't allowed in DC anymore, but may be legal in Philly or Baltimore.

Further Reading

Example of a popup turning a two story rowhouse into a 5-story triplex. Note six-story apartment building on same block. https://dcist.com/story/13/03/29/v-street-pop-up-is-a-big-middle-fin/

DC votes to put strict limits on popups in 2015 https://ggwash.org/view/38421/rowhouse-pop-up-restrictions-get-much-stricter-at-the-eleventh-hour

Summary of 2015 changes https://dc.urbanturf.com/articles/blog/pop-up_proposal_brings_heated_debate_to_zoning_commission/9413

Background info on popups https://wamu.org/story/15/01/26/whats_up_with_pop_ups_heres_a_primer/

Different types of DC zoning https://ggwash.org/view/62811/game-of-zones-other-side-of-the-bracket



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