"The house upon completion shall become the narrowest house in Warsaw, measuring...

Tiktaalik · on July 27, 2011

For "in the world" it may be between Vancouver's Sam Kee building http://en.wikipedia.org/wiki/Sam_Kee_Building and Pittsburgh's Skinny Building. http://www.post-gazette.com/pg/04151/322795.stm

Vancouver's building is thinner at the first floor, but has overhangs on the second which increases its width.

Edit: Hmm this is for "commercial" properties so there may be thinner houses.

Tiktaalik · on July 27, 2011

Vancouver Chinatown buildings are pretty interesting. There's also a number of buildings with 1/2 floors. http://scoutmagazine.ca/2011/07/21/secret-city-on-buildings-...

LiveTheDream · on July 27, 2011

Apparently the world's current official narrowest house is narrower at the front (47 inches) but expands to 22 feet. This one will be a bit under 60 inches the whole way through. By average width, this will be the narrowest in the world, not just Warsaw.

biot · on July 28, 2011

Other key phrase: "upon completion" -- the project date is listed as December 2011 and often these artist concepts don't see the light of day.