Window Sill Replacement

When it's time to replace, not patch

A patch holds when the damage is small and the rest of the sill is sound. Once you've got rot spreading along the full length, decay reaching back to where the sill meets the casing, or active leaks below the window, replacement saves you time and money over a string of repairs.

How we approach a sill replacement

1. Remove the failed sill

We carefully remove the existing sill without damaging the surrounding casing. If the casing has rot at the joint with the sill, we address that at the same time so the replacement isn't compromised on day one.

2. Inspect the substrate

What's behind the sill matters as much as the sill itself. We check the sheathing, the WRB, and the framing for moisture damage. If any of those need attention, we handle them before the new sill goes in.

3. Correct the slope and flashing

A sill should pitch outward so water can't sit on it. We re-establish the correct slope and install or correct sill-pan flashing where required so the new sill doesn't end up failing the same way.

4. Install the new sill

We prime all six sides of the new sill before installation, fasten it correctly for the material, and seal the right joints. Wrong joints sealed will trap water inside the wall — we leave intentional weeps where they belong.

5. Finish to match

The replacement is caulked, primed, and painted to match the rest of your trim. From the curb, it should be invisible.

Material choices

Cellular PVC

Our default for replacement sills on most Nashville homes. PVC will not rot, doesn't feed insects, and stays dimensionally stable. It costs more up front and pays off over decades of weather.

Fiber-cement or composite

Strong performance in humid climates, closer-to-wood appearance, and fewer movement concerns than PVC. Cut ends and fastener holes must be sealed during install.

Cedar or matched wood

For historic homes where authenticity drives the choice, cedar is a defensible option. We mill profiles to match originals so replacements blend with the home's character.

What's included

• Removal and disposal of the failed sill
• Substrate inspection and repair as needed
• Sill-pan flashing correction
• New sill installation in your chosen material
• Priming, caulking, and finish paint to match
• Cleanup and haul-away

If you're not sure whether your sill needs a targeted repair or a full replacement, that's exactly the kind of thing worth a free professional look.