I found a little section discussing housing in Philadelphia at the turn of the century, and they describe the "bandbox house" of Philly, more commonly called a "trinity" today.
"Perhaps you may ask what we may learn from Philadelphia. It seems to me that the principal lesson to us of Chicago was that unworthy standards are perpetuated, generation after generation. For many years the people of Philadelphia have been in the habit of building narrow houses, and they deem it a mark of advancement when they prescribe, as they have recently done, that no house should have a less frontage than fourteen feet. They have houses fronting on very narrow spaces. I myself observed an alley, or street perhaps, running through the block eleven feet and five inches wide, and having on each side of it three-story dwellings. Of course, such standards seem to us out of the question. I am glad that we don't do it in that way in Chicago.
"We also saw an interesting type of house, which had never before been brought to my attention an individual house three stories high one room on a floor. They call this house the bandbox house because it is like a bandbox a yard high and a foot in diameter. I went to the upper story of such a house on a stairway the width of which was two feet and four inches, and it was not a straight stairway; it was winding. If it had been a little larger we might have called it a corkscrew.
"Chicago has 8,000 privy vaults, I am sorry to say. They are mainly in the outskirts of the city, in regions which are to a degree inaccessible by extensions of the sewer system. Philadelphia has 40,000 privy vaults, a great many of them in well built-up localities, where the main sewers are available, or where an extension of the sewer throughout the street will afford such facilities. We saw one region recently built up -- the houses were not older than one or two years -- in which there were 14,000 such privy vaults and surface drainage only for the houses. (p 411)