With all the attention given these days to architects, it should be little surprise that there’s a burgeoning market for their work.

No, not that work. Not shining riverfront condominiums or big-budget museums, but far-more-affordable architectural drawings. Everything from a rough idea sketched on a napkin to the meticulously crafted final illustrations used to present concepts to clients are being purchased by people who admire the buildings, appreciate the historical value of the depictions, or simply think they are beautiful in their own right.

“We can’t collect buildings,” says Chrysanthe Broikos, a curator at the National Building Museum in Washington. “So these are the next best thing. They’re works on paper that breathe life into what the architect was trying to say, what he saw as the inherent possibilities of what he wanted built.”

Architecture critics may scoff at the notion of architects selling their early drafts, but such original drawings have long been in and out of favor as collectibles. New York art dealer Max Protetch has been selling original plans and drawings by iconic designers Frank Lloyd Wright and R. Buckminster Fuller for years. And in the late ’80s and early ’90s, Christie’s and Sotheby’s got into the act, auctioning off original plans by Wright and others for tens of thousands of dollars. (Drawings by little-known architects can be found for as little as $1,000.)

Those plans and drawings, of course, weren’t meant to be sold and, for the most part, neither is the work of contemporary architects. However more and more living architects are becoming savvy about the commercial value of their workaday renderings (the material created for actual buildings) and have begun offering particular pieces in partnership with art dealers.

It helps that architects are excellent and distinctive illustrators, and typically their drawing styles nicely echo their design styles. Michael Graves’ renderings, for example, are awash in the signature pastels that define his postmodernism, while Zaha Hadid’s boldly abstract acrylics promise striking additions to an oeuvre that has already won her recognition as the first (and only) woman recipient of the prestigious Pritzker Prize. Daniel Libeskind brings his trademark anxious angles even to the gentle medium of watercolor, and minimalist Tadao Ando’s pencil sketches mark his Japanese paper with delicate lines.

Today, “classics” remain popular, with Wright drawings still available for less than $10,000 but with the potential to skyrocket, according to David Jameson of Chicago’s ArchiTech Gallery. In a fall show, he hopes to include a colored-pencil drawing by Wright of a prairie house from 1907—with supporting documents, such as vintage magazine articles—priced at around $125,000. That’s an extraordinarily large sum, Jameson says, but this is a “presentation drawing” (a carefully finished work made as a gift to an important patron or created as a marketing tool) that depicts the very essence of Wright’s style. Such pieces are found mainly in museums or Wright’s archives. So far, most Wright drawings, even those sold at auction, have been purchased for less than $50,000.

But, adds Jameson, even much smaller pieces by the masters can fetch tidy sums. “I’ve sold a beautiful 4-by-5-inch Louis Sullivan sketch of some foliage for a façade for $50,000,” he says. “And to him, it was originally just a pencil doodle.”