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How to Replace a Window Sill Outside Your Home

Window Repair

How to Replace a Window Sill Outside Your Home

Is it time to replace your outside window sill? This can help with insulation as well as improve the curb appeal of your Hamilton area home. If you know how to replace a window sill, you might be able to do so without hiring a professional contractor.

If your window sill is severely damaged, it may be time to replace your Hamilton windows. But if there is only minor damage, you can use this guide for replacing your outside window sill.

Damage to outside window sills is common, as your windows age due to exposure to weather elements. It is simple to replace the window sill without removing the woodwork or interior window sash. Again, if there is severe damage to the window sill either inside or out, you will need to hire a professional to complete the job.

The Following Are the Steps for Window Sill Replacement

Tools needed:

  • Caulk
  • Chisel
  • Circular Saw
  • Hammer
  • Masking Tape
  • Miter Saw
  • Plastic Sheeting
  • Pry Bar
  • Reciprocating Saw
  • Safety Goggles/Glasses
  • Table Saw
  • Two-by-six Fir Lumber

*The thickness of your window sill may be different from the standard size, so be sure to measure before replacing.

*If your window sill extends beyond the trim, you should nail an additional piece of 1 ¼ inch fir lumber to the exterior edge.

Step 1: For exterior window sill replacement you have to after opening the window, to prevent sawdust from getting inside your home, tape plastic of the window’s interior. Once you have obtained the size and thickness of the window sill, you should set the blade on your circular saw to match that measurement.

Step 2: Placing the saw on one corner of the lumber, tilt it up to 30 degrees before turning it on. Carefully low it until the blade cuts into the sill, making sure that the base is flush to the sill. Pushing it forward, slowly guide it along the window sash’s edge. Stop sawing once it has reached the other side. Finish cutting loose the remainder of the sill with the reciprocating saw.

Step 3: Use the circular saw to cut the window sill across, in the middle, and perpendicular. Next, from the front of the sill underneath, insert the pry bar and pry out one piece at a time, going upward. 

Step 4: Using the chisel under the trim and in the corners, cut off any remaining pieces of broken wood. To get the edges square and clean, you can use a hammer to pound the chisel. Using a broom and wire brush, clean any remaining residue.

Step 5: Under the window trim, measure the distance between the sides.

Step 6: Cut the two-by-six fir lumber length to the measurement you obtained using the miter saw.

Step 7: Measure the width of the sill and cut off the lumber to the proper measurement, using the table saw.

Step 8: Using the hammer, pound the new sill into place. Place a wood block to protect the window sill from the strength of the hammer. 

Step 9: Apply caulking underneath and to the perimeter of the window sill. Paint or stain if needed.

Need more advice on how to replace a window sill? Contact Total Home Windows and Doors for expert consultation and a free estimate for window replacement tasks for your home today.

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