Ceiling

A ceiling is an overhead interior roof that covers the upper limits of a room. It serves as a finished surface for indoor spaces. Most ceilings are not considered structural elements of a building. Instead, they conceal the underside of a roof or the floor of the story above. In some cases, a ceiling can also be the upper limit of a tunnel.

One common method of construction is the dropped ceiling. This type is built anywhere from a few centimeters to several meters below the main structure. This gap creates a useful space for many different things. Builders can run mechanical and electrical pipework or ducts through this area. They can also place insulation or fireproofing material in the gap. A dropped ceiling may be used for aesthetic reasons to reach a specific height. It is also used for acoustic damping to control sound. This concept is the inverse of a raised floor.

There are several ways to build these surfaces. One method uses panels of drywall fastened to ceiling joists. Sometimes, builders attach drywall to moisture-proof plywood first. Other builders may choose to spray paint the area instead. This method leaves the pipes and ducts exposed but painted. They might also use spray foam for this purpose. A specific type of dropped ceiling is the suspended ceiling. This system uses a network of aluminum struts attached to the joists. These struts form rectangular spaces. Individual pieces of cardboard are then placed into the bottom of these spaces. This makes repairs very easy for workers. They can simply lift off the cardboard to reach the pipes. They do not have to dig through drywall and replace it.

Ceilings come in many distinct shapes and styles. A cathedral ceiling is a very tall area similar to those found in churches. A concave or barrel-shaped ceiling is curved or rounded upward. This shape is often used for visual or acoustical value. A coffered ceiling is divided into a grid of recessed panels. These panels can be square or octagonal. They are also known as a lacunar ceiling. Another type is the stretched ceiling, which uses panels of material like PVC. These panels are fixed to a perimeter rail. Finally, a cove ceiling uses a curved plaster transition between the walls and the ceiling. This transition is often called coving and uses concave cove molding.

Decoration has been a major part of ceiling history. Many historic buildings feature celebrated ceilings. For example, Michelangelo painted the famous Sistine Chapel ceiling. Artists often use fresco painting, which is a type of mural, to decorate these surfaces. They may also use mosaic tiles or other surface treatments. Decorated ceilings have a special advantage. They are largely protected from damage by dust or fingers. However, in the past, smoke from fireplaces or candles caused significant damage. The height of a ceiling can also have psychological impacts on the people in a room. This is especially true for low ceilings.

Ceilings also play a vital role in fire safety. The dropped ceiling is the most common type used for fire-resistance ratings. This rating is achieved by the entire system. It includes the structure above, such as a timber or concrete floor. It also includes the suspension mechanism and the lowest membrane. There is often room between the structure and the membrane for wiring and ducting. Some ceilings are built as independent systems. These must have a stand-alone fire-resistance rating. They must be tested without being suspended from a slab. This proves the system can hold itself up. These systems are installed to protect items located above the ceiling from fire.

Understanding ceilings helps us see how buildings function. They connect the structural needs of a building with human comfort. They manage sound, light, and temperature through insulation and height. They also manage safety through fire-resistance ratings. Whether they are simple drywall or complex coffered grids, they complete our indoor environments.