Other details that help rough-date a house include nails, paint colors, and molding and muntin profiles. Before the 20th century, all of these had styles particular to certain eras. (The manufacture of building materials became fairly standardized by the late 19th century.) The type of nails in the frame, for example—wrought, cut, or wire—direct the fastener-educated to a particular period. Professionals can help date elements of a house by examining a cross section of a paint chip, says Brian Powell, an architectural conservator with Building Conservation Associates. If Powell finds that a room had 10 layers of paint, for example, but a door casing only had the last eight, he would then know that the casing probably appeared around the same time as the third layer of paint on the walls. Chemical qualities of that layer might link it to a period of manufacture.

Hardware also tells a story—albeit a difficult one to decipher because sophisticated hinges and bolts were available from Europe at the same time that early local hardware remained relatively crude. But if a hinge design, for example, matches the estimated date of a door, and that hinge shows no sign of having been changed (paint irregularities and superfluous screw holes are big clues), then it may confirm the estimate. On the other hand, if the hardware is from the days of mass production—from the Victorian era on—old catalogs, available in many university libraries or historical societies, become a great resource. When all the available clues are taken into consideration, the possible construction date of a house ideally falls into a 10- or 20-year window: "That's about as good as most of us can do," says Gilmore. After looking over the Schondorf house, John Milnes Baker, a Katonah, N. Y., architect and the author of American House Styles: A Concise Guide, agreed that the authentic Greek Revival style meant a post-1820 construction. Noting the wood gutters built into the eaves—which didn't show up till 1840 or later—and the materials used in the frame, Baker deduces that the house went up around 1850.
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