On Google Maps, this landmark is called Holbrook Tower Windmill, though most locals call it the Hyannisport Lighthouse, or even the “Salt Shaker.” But it’s actually a former water tower, built in 1907 to supply water to the nearby Holbrook Cottage, a private home perched on the village waterfront. When the sunlight reflects off its new copper roof, it’s easy to understand why visitors to Cape Cod’s Hyannisport, Mass., might misidentify this structure.

We installed that roof last year as part of a major renovation of the tower itself. Once, the tower was equipped with a 14,000-gallon cypress water tank on the top level and an area for coal storage in the base, but it had been converted to an artist’s studio in the 1980s. When the current owners purchased the property in 2012, they had plans to renovate the tower along with the house and carriage barn, a project that picked up steam in 2020. I became involved after the general contractor—E.B. Norris—removed the tapered octagonal roof and trucked it off-site to rebuild the roof framing and install new sheathing.

The tapered octagonal roof is removed.
The tapered octagonal roof is removed.

We were fortunate to be able to do most of the copper work off-site too, starting by covering the new sheathing with Carlisle WIP 300HT, a high-temperature, self-adhering roofing underlayment suitable for use under metal roofs. Next, we installed a copper drip edge that we had fabricated around the perimeter of the roof, sealing the drip edge to the underlayment with Zip System flashing tape applied over the drip-edge flange.

We fabricated the drip edge from cold-rolled 20-ounce sheet copper from Revere Copper Products, the same material we used for the tapered roof panels. Following the project architect’s specifications, we joined the panels together and to the drip edge and hips with flat-lock seams, using as few soldered joints as possible.

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With the rebuilt roof propped up offsite on saw horses, workers installed copper drip edge around the perimeter of the roof, then the tapered panels (top left). The panels, drip edge, and hips are joined together with flat-lock seams and concealed copper clips so the panels can expand and contract (top right). The flat-lock seams are all malleted down (bottom left). Panel installation (as well as the sheathing) is run short of the roof peak to allow a lifting strap to be fastened to the framing of the upside-down-teacup-shaped structure so that it can be craned back into place on top of the tower (bottom right).
With the rebuilt roof propped up offsite on saw horses, workers installed copper drip edge around the perimeter of the roof, then the tapered panels (top left). The panels, drip edge, and hips are joined together with flat-lock seams and concealed copper clips so the panels can expand and contract (top right). The flat-lock seams are all malleted down (bottom left). Panel installation (as well as the sheathing) is run short of the roof peak to allow a lifting strap to be fastened to the framing of the upside-down-teacup-shaped structure so that it can be craned back into place on top of the tower (bottom right).

Because the octagonal roof needed to be lifted back into place on top of the tower with a crane, the carpenters omitted sheathing from the very top of the roof so that the riggers could attach the crane’s cable directly to the rafters. They also fabricated a separate bell-shaped finial to match the original out of solid pressure-treated lumber that we clad with soldered copper panels. The finial has a hole bored through the center for a solid copper lightning rod, which is attached to a braided copper wire that extends all the way down through the structure to a rod driven into the ground.

The bell-shaped finial (formed over a molded solid piece of PT wood), lightning rod, and braided copper wire prior to installation.
The bell-shaped finial (formed over a molded solid piece of PT wood), lightning rod, and braided copper wire prior to installation.

After the riggers lifted the roof into place and carpenters reattached it to the 60-foot tower, we installed the final course of sheathing, membrane, and copper roofing, working from an aerial lift.

Finally, we installed the finial, carefully soldering it in place so that the new roof would withstand another 100 years of getting hammered by coastal wind, rain, and sun.

After lifting the rebuilt roof into place (left), J Bennette Roofing crew members put the finishing touches on the “Salt Shaker’s” roof overlooking the Hyannisport harbor (right).
After lifting the rebuilt roof into place (left), J Bennette Roofing crew members put the finishing touches on the “Salt Shaker’s” roof overlooking the Hyannisport harbor (right).
After sheathing and installing ice-and-water shield, workers installed the final copper apron pieces needed to enclosed the roof.
After sheathing and installing ice-and-water shield, workers installed the final copper apron pieces needed to enclosed the roof.
With the copper panels capped with an octagon-shaped apron and soldered finial, the roof of the "Salt Shaker" is ready for another 100 years of duty.
With the copper panels capped with an octagon-shaped apron and soldered finial, the roof of the "Salt Shaker" is ready for another 100 years of duty.

Photos by Jim Bennette and Tim O’Neill