Courtesy PFC Auctions

A set of rumpled working blueprints for Fallingwater, Frank Lloyd Wright’s masterpiece in western Pennsylvania, that has been traveling across continents since 1938 is now for sale. Online bidding ends Sept. 27 for the package of 12 pages plus authentication material, which PFC Auctions in the Channel Islands has estimated will bring in at least $13,000.

The blueprints’ journey from the rocky Pennsylvania job site to Guernsey is complicated but somewhat traceable.

According to the accompanying paperwork, a sales representative from Hope’s Windows, the upstate New York manufacturer of Fallingwater’s steel ribbons and casements, gave the sheets to an architect in Waukegan, Ill., named Arthur Hennighausen, in 1938. He specialized in low-slung masonry school and religious buildings, often with Wrightian cantilevered overhangs and ribbon windows. A few of his works now appear on landmarks registries, such as St. Martin’s Episcopal Church in Des Plaines, Ill., with dalle de verre strips wedged between bricks.

The Fallingwater pages perhaps made Hennighausen design with more sympathy for his own roster of window contractors. The margins are littered with persnickety instructions about where to hinge joints, conceal bolts and add friction pivots.

Hennighausen, who died in 2007 at 94, apparently put the paperwork on the market before his death, and it has since gone through a series of memorabilia dealer middlemen. In 2006, the blueprints were offered at Heritage Auctions in Dallas, but they did not sell. According to the catalog, they were believed to be “the only ones in private hands.”

But in truth, other blueprint sheets are floating around. “We see them periodically coming up,” says Lynda Waggoner, the director of Fallingwater. Institutions including Columbia University’s Avery Library own sets, she added, and Fallingwater keeps copies on hand for researchers to pore over.

In June, a blueprint for the back wall of the house’s guest wing brought $27,970 at RR Auction in Amherst, N.H. That auction lot came with a ranting letter from Wright. The project’s hapless builder Walter J. Hall had given advice to the client, Edgar J. Kaufmann, behind Wright’s back and dared to express pity for the underpaid Wright apprentice, Bob Mosher. Wright’s note blistered Hall for “mischievous interferences” and accused the builder of having “never heard of ethics.” (The letter and blueprint had long belonged to Hall’s estate.)

PFC would not disclose details about the current consignor of the Hennighausen set.

There is one more unsolved mystery about the auction lot: When it came up at Heritage there were 13 pages, and now there are 12. Which suggests that yet another Fallingwater blueprint has been unmoored for further travels on the market.