Preservation groups are placing ever greater emphasis on preserving modernist buildings. Two early modernist town houses a block apart in Turtle Bay can help you decide what you think of this emphasis. One of the houses is already a designated landmark; the other is a prospective landmark.

At 211 E. 48th St., between Second and Third avenues, the Swiss-born architect William Lescaze remodeled an old town house into what may have been, when it was completed in 1934, the first truly modernist building in New York City. From around 1910 or so, architects had been busy remodeling 19th-century town houses, discovering that the old 20-footwide redbricks and brownstones were marvelously adaptable structures. They began removing high stoops, supplanting brick façades with stucco, and installing window boxes of cascading flowers. A city row house could be rearranged to suit one family, or two families, or six families, or 20 boarders — or, as Lescaze and others showed, family quarters plus an architect’s office. While earlier town-house renovators such as Frederick Sterner made over 19th-century houses into Tudor or Mediterranean fantasies, Lescaze dispensed altogether with picturesque allusions to the past or to other places.

Lescaze had, with George Howe, recently designed the Philadelphia Saving Fund Society Building (1929–32), at Market and 12th streets in Philadelphia. (It is now the Loews Philadelphia Hotel.) This is arguably the most celebrated early-modernist skyscraper in the world. With its cool curves, rhythmically banded windows, stylized lettering, and polished surfaces, the PSFS Building (as it is called) appeals even to people who don’t generally enjoy modernist high-rises. Hot off his PSFS success, Lescaze adapted its basic form to Manhattan rowhouse dimensions.

Just as the Philadelphia skyscraper has a dramatic curving base, with a curving-glass ribbon window, and a recessed entryway, so too, albeit at a much smaller scale, does the house. While the skyscraper’s tower is set back from its base, Lescaze, unable to do just that with a row house, evoked the setback by projecting a curving canopy over the doorway on the left side of the house. Up above, for the two floors of the “tower” portion of the house, Lescaze used full-height, full-width windows of glass block. This was one of the really hip materials of the 1930s, and Lescaze was a pioneer of its use here in New York. (Its first use here was probably the ornamental front window of the RCA Building at Rockefeller Center, only slightly before this house.) Glass block allowed in light while retaining privacy. It makes for an interesting contrast with today, when expansive windows are all the rage in new apartment buildings, though seemingly with the very purpose of letting people see in, as architects collude in the culture’s devaluing of privacy.

A block away, at 219 E. 49th St., the architect and industrial designer Morris Sanders created a self-consciously futuristic town house in 1935. At the time, he received a great deal of publicity. The Landmarks Preservation Commission held a hearing on the house last fall, but did not rule on it. The house will come up again, and preservation groups generally support its designation.

As with the Lescaze house, we can see that the architect was concerned with bringing as much light inside as possible. On the first, third, and fifth floors he used glass block, though with five-paned conventional windows set into the great glass-block expanses. At the second and fourth floors, Sanders created loggias, with deeply recessed full-height, full-width windows. The second and third floors formed one apartment, the fourth and fifth another, so that each duplex had its loggia. The ground floor was where Sanders put his office, just as did Lescaze.

Sanders cantilevered the two apartments over the ground floor, and propped them up on a slender pier, similar to the pilotis, or stilt-like piers, Le Corbusier had recently used in his enormously influential Villa Savoye (1929) in the Paris suburb of Poissy. Sanders bows again to Le Corbusier with the sleekly curving, white-stucco flower-box set before the glass-block wall. Up above, though, Sanders turned from Corbusian whitewash to a startling glazed blue brick, meant to resist the city’s grime. Inside, Sanders created an early sealed interior, air conditioned both for quiet (the elevated railways on Second and Third avenues were still operating when this house was built) and to keep out dirt. A hygienic impulse underlay a good bit of early modernism, which was at times bound up with the cults of exercise, healthy eating, and nudism.

I must say the Sanders house is not to my taste. But I am fascinated by architectural outliers, which this house was in 1935 and continued to be, as Manhattan modernism evolved in a different direction from this.