Upper Lantern, before. Photo by author

The East Derry crew has been hard at work completely rebuilding the belfry, lantern and upper lantern. The framing is complicated, and heavy. Each lantern is a separate, eight-sided tier, connected by a sweeping skirt roof. Below the lanterns, the belfry may only have four sides, but the bell itself is supported on a hip-roof floor made out of woven grid of 12″ x 12″ oak. The entire frame needed to be rebuilt. We used white oak, the same species as the original; it clocks in at about 83 pounds per cubic foot.

Stacked sweep. Photo by author

PTF specializes in traditional, in-kind repairs, which means we replicate the original design in the original species. While we believe in preservation, we make our decisions based on evidence. It is hard to argue with a design that has lasted 200 years. The sweep roof between the upper and lower lantern is one exception. Originally built out of stacked 2″ thick dimensional lumber, it certainly wasn’t constructed 200 years ago. The flashing failed, resulting in the catastrophic destruction of the framing below (next week on PTF blog – a whole host of hollow posts).

Dave applies the original torus trim to the sweep. Photo by Brian Cox

We carefully documented the sweep’s dimensions and radius, and constructed a new roof using radiused rafters. The resulting roof is precisely the same shape, but lighter, stronger and less susceptible to moisture infiltration. Above, Dave returns the original torus molding to the newly framed roof. It is hard enough getting miter joints to close on a four-sided building, and much harder at eight. The torus joints came together like they were going home, evidence that the crew achieved an exact replica.

Have you ever seen such gorgeous sheathing? Photo by Brian Cox

The upper lantern was completely assembled at our shop in Nottingham. It will be clad in wide Eastern White Pine, sourced locally, and trimmed in African Mahogany, which was a concession to the species’ superior consistency in milling, and comparable weather resistance. The sides were preassembled in panels and then removed so that the siding can be applied over the copper flashing at the connection with the sweeping roof.

Wedding topper. Photo by Brian Cox

The lantern is roofed with an octagonal wedding cake, which is penetrated by a mast that extends through the center of the frame and lands on the lower lantern’s bed timbers. The mast was originally scarfed together from three timbers. We reproduced that design, which will ease the assembly process and transport to the copper shop. The original lapped scarf is visible in the photo of the stacked roof.

Soldering the skirt. Photo by Brian Cox

In his report, Arron noted, “The sweeping roof is perhaps the most important roof on the entire tower. It is here that poor roofing allowed water to penetrate into the center of the tower and rot both the upper and lower lantern frames.” At the Heritage Company, in Waterboro, ME, Victor Wright and his crew redesigned the flashing details to ensure that they will be impervious to weather.

Up next week: the consequences of poor flashing, and reproducing the lower lantern frame.