In most places, greenhouses are structures used to grow plants. In New York City, they’re used to grow apartments.
From around the late ’60s through the early ’90s, many apartment dwellers fortunate enough to have a balcony or terrace put it under glass to make their patch of outdoor space habitable all year long.
They called the enclosed area a “temporary structure” (though dismantling it really wasn’t part of the plan) to exploit a building code loophole, closed several years ago, that didn’t count such an addition when calculating floor area ratio, a figure that helps determine how big a building can be. And code enforcement is about to get more rigorous.
The label “greenhouse” was as misleading as the label “temporary structure.”
“People may have put their pot plants there or a potted plant there, but the point was really to create more indoor space,” said Howard L. Zimmerman, an architect who specializes in exterior facade restoration. He estimates that there are thousands of these greenhouses or, as the Department of Buildings calls them, sunrooms, in New York City. […]