Start by determining the size of the existing mirror as well as the new frame. In this case, the mirror was 84” x 36”. With this size, I knew I wanted to frame it with 1x4 for good proportions. Because of the overall style of the bathroom, squared cedar was selected as the frame material. However, this method can be used with any wood type of at least 3/4” thickness, including ornate trims. Since this frame is “floating” on (not attached to) an existing mirror already mounted to the wall, a margin of overlap is left to conceal the edge of the mirror. Be sure to leave at least 2” of material to the outside of the frame, so it can be properly joined in the corners.
Cut the Frame
Once your frame dimensions are known, cut the four sides 1” longer than that final size. In order for
the frame to mount flush against the wall, a notch must be cut into the backside of the frame pieces.
Measure the thickness of the mirror and the bottom track (if any). The deeper of the two will be the
depth of the notch. Using a table saw, set the rip fence to remove that width. Since 2” will be left to join
the corners, the height of the cut will be 1-1/2" (for a total of 3-1/2" for 1x4).
Next, reverse the saw settings. Make the blade height the rip width and the width the height. This will
remove the remaining portion of the notch.
Miter the Corners
Using a miter saw, cut each end at a 45 degree angle. The total length of each piece will be measured
from tip to tip (the long end of the miters), in this case two at 88” and two at 40”.
Joining the Pieces
Using a pocket-hole jig, drill a screw hole in each end of the short (or side) pieces. Make sure to drill
through the center of the full-depth portion.
Layout the frame, face down, onto a flat surface. Make sure each corner fits clean and tight. Spread a
small amount of wood glue on each face, and join with a coarse thread pocket screw. If any corner is
slightly twisted, an 18-gauge finish nail through the corner can be used to pin it until the glue dries. Allow
to dry for at least two hours.
Finishing the Frame
Once the glue has dried, finish the front with your choice of treatment. In this case, I wanted a white
wash to show the beauty of the cedar grain while toning down the reddish color. To white wash, apply
any white paint with a brush, and then wipe back with a wet rag. Wipe until you achieve the desired
Mount the Frame
Test fit the completed frame over the mirror, and make sure it fits flush to the wall. Most frameless
mirrors that are not fully adhered will have some sort of retainer at the top. The plastic retainers on this
mirror were too deep to notch into the back of the new frame. An old sink drain strap was cut into two
small pieces to replace the plastic retainers. Dab a small amount of caulk between the mirror and the
wall, the mirror and the strap, and lightly tighten the screw.
Lastly, using a studfinder, mark all stud locations on the wall in the area of the frame. Dab caulk on the
backside of the frame corners and in the middle of the long horizontals. Shoot one 2” 15-gauge finish nail
into the top and bottom horizontals of the frame at each stud location.