Having a mirror hanging over your fireplace mantlepiece helps to create the illusion of a more spacious room. A mirror also adds more light to the room if it reflects a window or a lamp. How you hang your mirror can also add something special to the look of your fireplace and room. If your mirror is rectangular, decide if you want the mirror to hang in a landscape (horizontal) style or in a portrait (vertical) style. If you decide not to hang your mirror, consider leaning your mirror on the mantlepiece -- another creative way to bring focus to your mantlepiece.
Measure how the distance above the mantlepiece you want your mirror to hang. Measure from the mantlepiece up rather than from the ceiling down. This will make your mirror appear much straighter and allow for irregularities in the evenness of your mantlepiece. Make certain you do not hang your mirror too high. This creates a disconnected look.
Lift your mirror into the desired position above the mantlepiece. For large, heavy mirrors always have another person help you lift it into place. Lightly mark the wall at the top of the mirror on each side with your pencil.
Lightly mark the wall at the top of the mirror on each side with your pencil. Set the mirror down. Draw an even, straight line across the pencil marks.
Use your stud finder to locate studs in the wall behind the mantlepiece. With your pencil, lightly mark the edge of each of the studs you find.
Place a piece of clear tape on the wall to indicate the centre of the studs. Draw a line 10 to 12.5 cm (4 to 5 inches) from the centre of the studs to the top line you made for the top of your mirror.
Use a pair of triple-nail picture hangers. These are easily found at home improvement centres, hardware stores or picture framing stores and are made to hold mirrors that weigh up to 45.4kg (100 lb). Space the hangers 30 cm (12 inches) apart along the studs, marking the locations with your pencil. Picture hangers keep your wall free from unsightly holes, should you decide one day to remove the mirror. Using a pair allows the mirror to hang evenly and with extra security.
Hammer in the nails -- at an angle -- into the studs to attach the picture hangers. These nails are found in the packaging with the picture hangers.
Locate the mirror's centre and secure the two sets of hanger hardware to the back of your mirror, following the manufacturer's instructions.
Hang your mirror over the fireplace mantle, slipping the wires securely in the picture hangers.