Every year when the weather cools in Bend, the puffy jackets come out of storage, pumpkin beers find a spot on tap lists, and the roof over the outdoor pool at Juniper Swim & Fitness Center is hoisted back into place.

Bend Park & Recreation District employees and temp workers got started putting the roof on Monday, and expect to have the transition complete sometime this weekend.

Sue Glenn, recreation services manger for the district, said the roof goes back on in early October most years, regardless of weather conditions. Even in years when summer-like conditions persist through fall, colder weather is just around the corner, she said.

Once the roof is in place, the 50-meter pool will remain open through the winter. The smaller, indoor pool is not affected by the transition.

The pool stays partially open during the transition period. With swimmers still swimming in one 25-meter half blocked off from the rest of the pool with a bulkhead, crews worked to put the roof up over the other half. Once half the roof was up, swimmers were moved beneath the recently installed roof while the crew shifted to the other half.

The roof consists of 28 separate panels, each 100 feet long by just under 141⁄2 feet wide, and weighs somewhere between 400 and 600 pounds. Each of the panels is secured to the series of steel, rib-like supports that stand above the water.

This winter will be only the second year of service for the current roof. Where the old roof had only a single layer of rubberized cloth, the current model has both inside panels and outside panels, creating a roughly foot-thick pocket of air between the two for insulation purposes.

Glenn said the double-layered roof helps reduce the cost of keeping the pool area warm in winter. She said the district tries to maintain water and air temperatures of 80 degrees through the winter months.

The roof assembly is a laborious, hands-on process requiring a crew of eight for nearly a week of work.

A length of nylon rope threaded through channels in the supports is used to pull the roof into place — one end of the rope secured to a hook on the edge of the panel, the other looped through a series of pulleys on the opposite side of the pool and secured to the bumper of a park district truck. Backing the truck up 50 feet or so pulls the panel halfway into place, after which the ropes are tied off and the truck returns to its original position for a second pull.

Glenn said pulling the roof into place can be like fussing with a troublesome zipper. If one edge of a panel is pulled too fast, it will jam in the channel, forcing the installation crew to back it out and start over.

To keep it all moving smoothly, the channel is continuously lubricated with silicone spray.

Glenn said as of Tuesday morning, all of the exterior panels were in place, and the crew was preparing to install the interior panels. She said the walls at the far ends of the pool should go up this weekend, completing the transformation from outdoor pool to indoor pool.

— Reporter: 541-383-0387, shammers@bendbulletin.com