How to Build a Refracturing Sill

In older homes, and newer ones still “settling” into place, window sills tend to fracture over time. Repairs must be done periodically, to prevent heat loss, block areas where insects get in, and help the window look well-maintained. Foundation flaws are one of the most common reasons why window sills fracture. And if left unaddressed, the sills may refracture year after year -- as the house continues shifting, sinking or settling. When you notice your window sills fracturing, get your foundation inspected as soon as possible. The earlier you resolve the foundation problem, instead of just fixing the fractured sills, the easier and cheaper it will be to repair.

Wood piece -- large enough to hold up the window
Crowbar
Wood putty
Saw
2-by-10 lumber
Hammer and nails, or wood glue
Caulk
Wood for top plate

Instructions

- 1
  Remove all coverings from the window.
- 2
  Brace the window up with a piece of wood, so it does not drop on you.
- 3
  Remove the top plate from the window frame.
- 4
  Remove the wooden window sill, using a crowbar.
- 5
  Check if there are any pieces of fractured wood below the sill. If so, remove them, and replace them with the same sized piece of wood in whatever material you have chosen.
- 6
  Fill any small nail holes or minor imperfections with wood putty.
- 7
  Cut a piece of wood to the size of the window sill. Ensure it will be a tight fit when installed.
- 8
  Slide the piece of wood into place, by placing the left side in place and sliding the wood toward the edge of the window frame, while pushing down on the right-hand side.
- 9
  If the wood gets stuck, remove it. Cut a small amount off the end, and place the wood in the window frame again.
- 10
  Once the wood is in place, nail it to the window frame, if possible. If this is not an option, use a strong wood glue to secure it in place.
- 11
  Caulk around the edges of the new window sill, to ensure moisture does not get into the wood.
- 12
  Replace the top plate with a new piece of wood, if needed, and secure it to the window sill.

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