Parts of the sills restored, 2003. Photo: TH
Sills

Rotting Sills
The formidable job of replacing the sills of the main building began in April, 2002. It was essential to repair them since they were rotted in places and beginning to roll, causing stress to the building’s walls. The sills of the towers were replaced in the mid-1990s (by Americorps). They had decomposed to such a degree that the towers were sinking four inches in places causing substantial stress to the structure.

Replacing the Sills
The first step in replacing the sills of the main building was to remove the remaining clapboards and sheathing lumber from the northwest and southeast sides of the building. The building was then jacked from inside the basement using a crib work of hemlock beams and ten 20-ton hydraulic bottle jacks (minimal jacking was the best way to prevent stress damage). The building was jacked a 1/4 inch higher than the new sills dimensions. The beams were pounded in place at 1/8 of an inch at a time. Workers struck on knots in the wood wherever possible in order to minimize damage to the beam. Several sixteen-foot, 8" by 8" hemlock beams were used for the new sills (from NC Hunt Lumber Co. in Jefferson, Maine). The new sills far exceed the strength and durability requirements for the building. They were set in place and then pounded in with a sledgehammer.

Nails holding the old sills to the floor joists and wall studs of the building were removed. The old sills were then cut into manageable sections for easy transport. They had to be removed in small sections (sometimes two or eight-foot sections). Immediately upon removal, a new sill was put in place. It was impractical and dangerous to jack the entire building at one time, and so only those sections worked on were jacked. Extensive rot had been filled in with concrete in 1989 when a new foundation wall was made. In some places, this concrete was four-inches high and four-inches deep. The excess had to be sawn out to ensure a level foundation. About a one-inch bevel of the concrete was also trimmed off along the entire foundation outside the original sills.

Other Considerations
Overall, the sill replacement for the museum went well, with only minor challenges. For instance, an electrical conduit was discovered running through the old sills at the entrance to the cellar on the northwest side of the building. To avoid damage to the conduit, twelve feet was cleared on the south side of the cellar entrance. The sill was inserted, then pounded and pried lengthwise along the foundation using blocking until in position. This task took an hour for four men, taking turns, to pound the sill into position. To reduce future problems, the new pieces were notched and joined where the conduit went through. The beams were ship-lapped to fit each other tightly to block wind and moisture from entering the basement. During installation, all seams were sealed with caulking and insulation to ensure long-term stability.

Final Steps
Once the new sills were firmly in place, bats of insulation were added in between the floor joists above the sills. Two layers of plywood and a 1-inch layer of rigid foam insulation were screwed to the outside wall studs to replace rotted wood. All seams were staggered to further block the weather. Exterior trim was attached using pressure treated lumber and hemlock planks. A six-inch bevel was added to divert water away from the sills and over the foundation.

Trim was installed using four and six-inch brass plated screws set into the sills and studs (screws will not pull out over time as nails are apt to do). Final steps included coating the trim with rubber caulking and epoxy and applying an oil base primer to shed water and protect the new woodwork. Two coats of water- based paint followed the primer. Repair and replacement of the sills was completed by fall, 2002.

Funders and Supporters

  • Private donors
  • Maine Historic Preservation Commission
  • Maine Acadian Heritage Council
  • John Dionne

Team

  • Terry Helms (sill replacement and trim work)
  • Bill Parent (sill replacement)
  • Marc Garcia (assistance and trim work)
  • Aurelle Collin, Don Cyr (assistance)