When Richmond, Calif., builder Pete Kasten accepted a last-minute commission to renovate a third-floor bedroom and bath in a historic 8,000-square-foot home north of the Golden Gate Bridge, he knew that the impending late-winter rains had the potential to wreak all sorts of expensive havoc on the site. The job - part of a regional event to showcase the work of residential designers - called for tearing off an existing 15-by-36-foot roof, beefing up the framing, and installing a new membrane roof and floating ipe deck. The new deck was to be flush with the bedroom floor and separated from it by a bank of accordion-fold glass doors, creating what the designer described as an "indoor-outdoor retreat."

To reduce the risk of flooding, Kasten arranged to have a local abatement contractor enclose the space above the deck with heavy shrink-wrap film, a material typically used to weatherproof large objects like boats, RVs, and modular home components. This, he hoped, would protect both his work area and the rooms below, where other contractors were hard at work on projects of their own. "It took us a day to set up the support structure and temporary railings," he says. "The wrapping crew came in, spread the film, and shrank it tight with propane torches the next day, and we were ready to go."

As luck would have it, the installation marked the beginning of a week-long dry spell. But when the rains did come, they came long and hard. "I'd been worried about it for days," Kasten says, "so when it started pouring, I raced over there to look, but it hadn't leaked a drop."

Not that the six-week job didn't pose plenty of other challenges. The house was packed with contractors and visitors, all of them jostling for elbow room on the crowded site. For one two-week period, the third-floor work area was reachable only by way of an outdoor extension ladder. The work had to be done to a very high standard, and the profit margin - as is usually the case with showcase projects - was razor-thin. "It would have been a total nightmare without the shrink wrap," Kasten says. "If the client is willing to pay the bill, that lets you do things you'd never do otherwise." - Jon Vara