A wall-to-wall mirror can add perceived depth and width to a small room, while greatly increasing its light and airiness. Follow the procedure below to install a wall-to-wall mirror.
Step 1: Decide on the Number and Size of Mirrors
Measure the height and width of the wall where you will apply the mirrors. You may need more than one size and type to fill the wall. Make sure you have identical mirrors across the center of the wall from 3 feet above the floor to 6 feet above the floor, where most people's "eye level" is located.
Leave no more than 2 inches total per side between mirrors to create the illusion of filling the wall with the mirrored surface. Extend the mirrors up the wall to within 6 inches of the ceiling, and to 18 inches above the floor to prevent breakage from contact with furniture.
Step 2: Prepare the Wall
Remove all paintings, chair rails, hooks, screws and other fasteners from the wall. If the wall is wallpapered, consider removing the paper as well, as a wall-to-wall mirror works best on a plain surface. Wash the wall with an all purpose cleaner and very hot water, to remove old paint, wallpaper glue and drywall dust where fasteners were extracted.
Add a fresh coat of paint to any areas of the wall that will not be covered by mirrors. Let this new paint dry overnight. Draw a fine pencil grid on the wall for the mirror placement. Check that your pencil lines are level and at a 90 degree angle with a carpenter's level.
Step 3: Apply Mirror Mastic
Run the mirror mastic adhesive diagonally every 2 to 3 inches across the back of the mirror and dot it into the corners. Keep it at least 1 inch from each edge of the mirror. Spread it out with a putty knife so it makes a uniformly thick layer over the mirror back.
Step 4: Attach Each Mirror
Attach each mirror to the wall in its place as shown by the pencil grid. Press the mirror firmly and accurately. The mastic adheres quickly and the mirror cannot be removed after contact with the wall.
Step 5: Care and Maintenance
Avoid obstructing the mirror wall with furniture, lamps and shelving. Polish the mirrors a few times a year. Dust the mirrors regularly to enable them to keep reflecting natural light and indoor lighting all around the room.
Step 6: Precautions When Designing and Installing a Wall-to-Wall Mirror
Always choose a wall at a right angle to a window as your mirror wall, to avoid reflections that will travel out through the window and blind pedestrians, cyclists and motorists. Select a wall that is well-fortified internally by studs because the weight of several mirrors can pull down a hollow interior drywall panel.