Frames rot from the bottom up. Water condenses on the foundation and rots the sill from below, or enters at the eaves and runs down the wall framing, rotting the sill from above. Some sills are sunk by splash back. In the dead of night, sill rot can haunt you; it seems catastrophic. But rotten sills are so common that their repair is our most standardized process, and can be buttoned up in a little over two weeks. We’ve repaired two church sills already this year. The jobs in Troy and Benton Falls ran smoothly and efficiently in the background, while we tossed and turned over pilaster this and custom-trim that. These sill jobs aren’t flashy, they’re basic (in the best way). They are also amongst the highest repair priorities, and essential to a building’s longevity.
We repaired Troy’s sill first, in January. A short section of sill was completely rotten. The building still has some of its original sill, but the rotted section had been replaced before, maybe 25 years ago, in hemlock. It had been damaged by splash-back off the propane tank and condensation resulting from drilling through the sill for the propane line. The sill was fairly low to the ground and drainage was poor (typical). There was no gutter, which is probably best for the building, but the ten inch overhang didn’t protect the sill from its fate. We connected the posts and studs with a tripled 2×10 ledger. On each post, we hung a stout metal L-bracket. We used hydraulic jacks, resting on short, angled dead men and cribbing, to take the weight of the wall off of the existing sill. The 20th century replacement was installed with a nice stop-splayed scarf, which we matched with our repair. The job took a little over two weeks.
Benton Falls Congregational Church
The north eave sill at Benton Falls succumbed to years of organic matter built up along the eave wall, which made the sill nearly earth bound. Poor drainage and splash back didn’t help its cause. This building was different from Troy in that the sills were resting upon original granite capstones that had sunk and shifted over time. Using a laser level up in the attic and measuring the height of the plate at each post, we determined that the rear wall of the building had dropped three inches. During the repair, the crew gently lifted the rear of the building so that it was returned to within a half inch of level. The crew then replaced the entire 8″ x 8″ x 42′ sill. It was in three pieces connected by stop splayed scarfs, like those used at Troy. The building committee has contracted with a company to improve the drainage around the building, and, while they’re at it, pick up the rear cap-stones and install solid stone shims beneath them.
You’d be forgiven for thinking I made a mistake and inserted the same lifting photo for Troy and Benton. Not so! The repair process was nearly identical. Don’t be afeared of sill rot. Just fix it, and sleep soundly.
