Installing a two-way glass mirror is as easy as installing an indoor window, but care should be taken so the right side of the mirror is facing the way you want it to. A two way mirror is actually two panes of glass pressed together. Before they are pressed together, one pane of glass is created exactly like a mirror in a process which is called silvering. On the other side of the same pane of glass, a reflective metal like nickel, silver, or tin is applied. Then the other pane of glass is fused on top of the painted metal side. This allows light to be reflected forward, so that somebody standing on the silvered side cannot see anything, while someone on the other side can see straight through.
Step 1 - Get Your Two Way Mirror
The two way mirror you should purchase or construct should already have a frame so that it is ready to be placed into the wall.
Step 2 - Mark and Make a Hole in the Wall
Measure the two way mirror you have, making sure that you are also measuring the frame as well, and mark on the wall you will be cutting into. Also remember that you will be constructing a frame inside the wall as well, so add another two inches on the top and bottom to account for it. Refer to your house blueprints or consult a professional to make sure the wall you will be cutting into is not a load-bearing wall. Also refer to your local codes and make sure you are not in violation of any restrictions set by the state. Once you have marked where you are making the hole, use the hammer and saw to cut into the drywall and saw the frame inside the wall. Do not cut more than you need to out of the wall.
Step 3 - Construct a Frame inside the Wall
Measure out and build a frame for the two way mirror by cutting your 2x4 to be placed on the bottom and the top where you have cut on the frame inside the wall. Use screws and the drill to firmly put them in place.
Step 4 - Put in Your Two Way Mirror
Put in the framed two way mirror making sure that the correct side is facing the right direction. If you put the mirror in the wrong way it will take a lot of time and effort to take it back out and turn it around. Hammer in finishing nails to firmly put the two way mirror in place. Make sure that you hammer the finishing nail all the way into the frame of the two way mirror, otherwise, you will have a piece of metal protruding that is unsafe. Use the plaster trowel to spread plaster over the area where you placed the finishing nail. Once the plaster dries use the sandpaper to sand it down smooth. Plaster any areas around the frame in the wall, let it dry, and sand it down.