A suspended or "dropped" ceiling, first common in office buildings and commercial spaces, is also popular in homes for certain types of rooms--notably basements, garage conversions, and recreation rooms. 
Made up of a grid work of metal channels that hold lightweight panels, a suspended ceiling hangs beneath the home's original ceiling or the underside of the floor above it, often concealing heating ductwork, pipes, other mechanical equipment, or a badly-damaged ceiling.
In a residence, the panels that fit into the grid are typically made from lightweight sound-absorbing mineral fibers and are sized 2-by-2 or 2-by-4 feet. Their sound-deadening qualities, especially when paired with sound-attenuation batts of insulation placed above them, can do a great job of controlling noise. Because the panels simply drop into the upside-down T-shaped channels of the grid work, they are easily removed for access to mechanical equipment in the area above or for replacement. Specialty panels and equipment such as fluorescent light fixtures and sound speakers are also designed to fit into the grid.
Leading manufacturers of suspended ceiling systems are Armstrong, Certainteed, and USG. Each make the panels in patterned, textured, and smooth designs. Some also produce metal-tile-like panels and wood-like panels.
A disadvantage of a suspended ceiling is loss of headroom. This type of ceiling literally "drops" the ceiling. So that panels can be pushed up through the grid and then set into place, a minimum clearance beneath the lowest objects (such as floor joists) is required--typically from 3 to 8 inches.
Installing a suspended ceiling is a fairly easy do-it-yourself project. Here’s how:
1. Start by calculating the height the ceiling will be. The minimum should be 7 feet, 6 inches, and it should also be 3 inches below any plumbing and 5 inches below any lighting. Once you have figured out the ceiling level, snap a chalk line to mark it. Then install the track supports so that they just cover the line.
2. Using tin snips or a hacksaw, cut the main tees to length. Place them on the track supports and hang them from the joists with #12 wire attached to eye screws inserted every 4 feet.
3. Insert the tabs of the 4-foot cross tees into the slots of the main tees and then snap them into place.
4. Lower the solid panels and any fluorescent lighting panels you are installing gently into place. Use a utility knife to cut border panels to fit. Before handling the panels, wash your hands well because smudges cannot be easily removed.
