How — To Repair Rotted Window Sills ((free))

He brushed the hardener into every pore of the cavity. It soaked in, sizzling faintly as it bonded with the remaining cellulose. After an hour, the soft edges turned rock-hard.

He brushed on an exterior oil-based primer, then two topcoats of satin latex. But the real secret came last: he did not caulk the bottom edge of the sill where it met the brick. Many people make that mistake. Caulk there traps water. Instead, he left a ⅛-inch gap—a “weep path”—so any future moisture could escape. how to repair rotted window sills

The next morning, he brought out two small cans from his workshop: a wood hardener (thin, like watery varnish) and an epoxy wood filler (thick, like modeling clay). He brushed the hardener into every pore of the cavity

Crucially, he checked beneath. Rot that goes all the way through the sill’s thickness and into the wall framing is a different beast. This was surface rot—deep, but not structural. Repairable. He brushed on an exterior oil-based primer, then

Old man Hendricks had lived in the gable-ended cottage for forty-seven years. He’d painted the clapboards, rehung the shutters, and swept the chimney every autumn. But there was one thing he’d ignored: the slow, silent drip from a cracked glazing bead on the east bedroom window. Every rainstorm, a teaspoon of water would sneak past the paint, lodge itself in the end grain of the sill, and begin its quiet work.

When you think you’ve removed enough rot, remove another half-inch into the healthy wood. Rot is like an iceberg; what you see is less than what’s there. Chapter Three: The Hardener and the Filler Hendricks vacuumed out the cavity and let it sit for a day with a small fan aimed at it. Wood must be bone-dry before repair.

By the time he noticed the problem, it wasn’t a drip anymore. It was a soft, crumbly patch of wood near the outer edge—dark brown, spongy to the touch, and flecked with the fine orange dust of dry rot.