How to Replace Old Windows With New Vinyl With Fins

Score along the seams of the interior window trim surrounding the old window using a utility knife. This will break the paint seal so that you can easily remove the window trim.

Slide the blade of the small flat bar underneath each length of window trim and pry up each piece of trim. Carefully remove each trim board from the window opening. Remove any stray nails that were left in the window opening using a nail puller. Carefully remove the top and bottom window sash and set them aside.

Saw along each side of the old window between the window frame and the rough opening from top to bottom using a reciprocating saw. Saw through the center of the window sill to cut it in half with the reciprocating saw. Pull in on the sides of the window frame and carefully remove it from the rough opening.

Remove any nails that may have been left in the rough opening with a nail puller. Brush out the rough opening with a shop brush.

Cut off the caulk tube tip using the built-in cutter on the caulk gun. Puncture the seal with the puncture tool on the caulk gun. Insert the caulk tube into the caulk gun tip first. Apply a bead of caulk along the sill of the rough opening with the caulk gun.

Lay shims across the sill every 6 to 8 inches. Pivot the replacement window into the rough opening, resting the sill against the sill of the rough opening. Place a level across the top of the replacement window sill.

Adjust the shims until the window rests level. Drive the installation screws that were provided with the window through the holes in the sill with a screw gun. Drive the installation screws through the holes in the fins on the exterior of the window into the exterior of the house using a screw gun.

Saw the shim boards flush with the edge of the window using a flush trim handsaw. Spray insulation into any gaps between the window and the rough opening. Allow the foam to cure overnight. Trim the foam flush with the window using a utility knife.