Windows see a lot of harsh weather during their lifetimes. If your home has wooden window frames, the sill can rot over time. Rather than having an expensive contractor replace the windowsill, do it yourself. Doing this for each of your windows as needed will result in major cost savings over using a professional.
You will need:
• 2” x 4” cedar material
• 1x cedar material
• Circular saw (type with dust collector)
• Table saw with dado blade
• Sliding compound miter saw
• Reciprocating saw featuring fine-tooth blade
• Pry bar
• Impulse nailer
• 16-gauge 2 ½-inch nails
• Wood filler
• Insulative paper
• Utility knife
• Safety glasses
Step 1: Use the utility knife to score the caulk located around the exterior of the window frame. Do the same thing inside the trim.
Step 2: Remove the exterior trim with the pry bar. Be careful not to damage it because this trim will be reused.
Step 3: Use the reciprocating saw to cut out the window. Have an assistant hold the window during this process to prevent it from falling and breaking. Use the saw to remove the framing member. It should cut through the nails.
Step 4: The wall cavity should be fine if only the top of the windowsill is rotted. If the sill is completed rotted, inspect the wall cavity for damage.
Step 5: Construct a new framing member, using the table saw and cedar material. Cut out a notch for the top. Secure the framing member into place, using some nails.
Step 6: Use the saw to cut a new sill featuring 2 x 6 notched corners, ensuring that the sill fits in the rough opening. Nail the sill in place.
Step 7: Using the dado blade on the table saw, make a kerf cut in the bottom of the sill. This enables water that drips off the edge of the sill to fall to the ground, rather than wicking to the rear of the sill and getting into the siding.
Step 8: If it is necessary, cut the siding with the circular saw to allow room for the new trim pieces. The saw blade should not be set to deeper than the siding.
Step 9: Use wood filler to fill the cracks or holes made by the pry bar or saw. Cover areas of exposed wood with the insulative paper.
Step 10: Fit the window in place, using the help of an assistant, if needed. Use the impulse nailer and nails to secure the window.
Step 11: Cut the trim to the proper size and nail it into place.
Step 12: Fill the nail holes with the wood filler. Allow the area to dry, sand it, and repeat the process, if needed.
Step 13: Prime and paint the new trim and windowsill.