How to Install Window Sill Molding


Window sills have the functional purpose of framing in the window, but they are also decorative. A nice piece of molding under the bottom sill of the window can dress it up immensely, and it's easy to install, whether in new construction or remodeling. When choosing the molding, either match the other molding in the room or find something that will complement it. Since molding isn't structural, you don't have to find studs to hang it, but adding glue is always a good idea.

Things You'll Need

  • Tape measure Pencil A piece of molding a little longer than the window sill Drill with pilot bit Carpenter's glue Trim nails Hammer Nail set Paintable caulk Painter's tape Paint or stain and varnish Brushes Miter box

The Steps

  • Measure the length of your windowsill from underneath.

  • Mark your molding at that length, and then take off one inch. Mark that measurement on your molding, set the molding on your miter box and cut to the mark.

  • Lay the molding piece on your work bench. With your drill and pilot bit, drill holes every six inches along the face, at an angle that will go from a half inch from the top of the molding and angle upward into the bottom of the sill. If your molding is more than two inches wide, drill additional holes a half-inch from the bottom of face, going straight through the wood.

  • Spread carpenter's glue along the back of the molding. Press it into place under the sill, leaving a half inch space at either end. Hammer trim nails into the top row of pilot holes, at an upward angle, into the bottom of the sill. Stop hammering just before the nail head gets to the surface of the wood, then use your nail set to punch it just under the wood surface. Repeat for the bottom row of nails, if there is one, hammering straight into the wall.

  • Caulk all seams between the molding and the wall, and the molding and the sill. Give the caulk a day to dry.

  • Tape off the sill and molding from the wall, and paint the whole sill, molding and frame assembly.

Tips & Warnings

  • Medium- or high-gloss paints are generally best for window frames and sills. If your molding is going to be stained and varnished rather than painted, stain it after cutting the piece but before hanging it, and apply one coat of varnish, then apply the second coat of varnish after the molding is hung.
  • When using drills, power miters or other power tools, wear eye protection.

Related Searches


  • Photo Credit
Promoted By Zergnet


You May Also Like

  • How to Install a Casement Window

    Casement windows are windows that swing out using a window crank, or, sometimes, just a manual push. They are not anymore difficult...

  • How to Trim a Marble Window Sill

    Marble window sills offer higher durability than wood or drywall finished sills. Cutting marble requires a blade capable of removing material without...

Related Searches

Check It Out

22 DIY Ways to Update Your Home on a Small Budget

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!