Ceilings

This is the interior portion of the roof and separated usually from the exterior roof by a crawl space. However, ceilings come in many different forms. There are flat ceilings with attic areas above, cathedral ceilings with attic areas above, cathedral roof-ceiling combination, or a flat roof ceiling.

Cellar

A story in a building whose floor line is below ground level at any entrance or exit, the ceiling of which is not more than 5ft above ground level whose primary function can be accommodation or storage.

Celsius

The metric temperature scale in which water freezes at zero degrees and boils at 100 degrees, designated by the symbol "C". To convert to Fahrenheit, multiply a Celsius temperature by 9, divide by 5 and add 32 (25 x 9 equals 225, divided by 5 equals 45, plus 32 equals 77 degrees Fahrenheit).

Cement

A substance made of powdered lime and clay mixed with water and used to fasten stones and sand together to form concrete.

Cement Blocks

Blocks composed principally of cement and gravel formed into shape under pressure typically used for walls.

Central Air Conditioning

A system which uses ducts to distribute cooled and/or dehumidified air to more than one room or uses pipes to distribute chilled water to heat exchangers in more than one room, and which is not plugged into an electric convenience outlet.

Centrifugal Fan

A fan in which the air is turned from parallel to the axis of rotation on entry to a direction tangential to the arc described by the tips of the rotating blades or vanes.

CFC

Acronym for Chlorofluorocarbon, which is a family of refrigerants that if released into the atmosphere are associated with the destruction of the Earth's ozone layer. A typical example is Freon (trade name) or R12.

CFM

Stands for Cubic Feet per Minute. A measurement of airflow that indicates how many cubic feet of air pass by a stationary point in one minute. The higher the number, the more air is being forced through the system.

Chalk Line

A line made by snapping a taut string or cord dusted with chalk. Used for alignment purposes.

Charge

To add refrigerant to a system. This is refrigerant contained in a sealed system or in the sensing bulb to a thermostatic expansion valve.

Chase

A groove in a masonry wall or through a floor to accommodate pipes or ducts.

Check Rail

The horizontal members or rails, that form the top of the lower sash and the bottom of the upper sash into a double-hung window two rails in combination. The bottom horizontal member of the upper sash and the top horizontal member of the lower sash which meet at the middle of a double-hung window.

Check Valve

A plumbing valve that closes automatically, preventing the backflow of water or other liquids. See Back Flow Preventer.

Childproof

An item designed to hinder entry by a child normally surrounding dangerous areas such as swimming pools.

Chiller

A heat exchanger using air, refrigerant, water and evaporation to transfer heat (btus) to produce air conditioning (measured in tons). A chiller is comprised of an evaporator, condenser and compressor system.

Chimney

A stack that extends above the surface of the roof and carries smoke outside.

Chimney Back

The rear wall of a furnace or fireplace.

Chimney Cap

Ornamental stone, concrete or metal edging at the top of the chimney stack that protects the masonry form the elements and improves the draft in the chimney.  Concrete capping around the top of chimney bricks and around the floors to protect the masonry from the elements.

Chimney Flashing

A strip of material, usually metal, placed where the chimney meets the roof to make the joint watertight used wherever the slop is interrupted by a vertical structure.

Chimney Pot

A fire clay or terra-cotta pipe projecting from the top of the chimney stack is decorative and increases the draft of the chimney.

Cinder Block

A concrete block made using cinders as the coarse aggregate to achieve a lighter weight.

Circlehead Window

A small half-oval window used for decorative purposes, usually over a door. It is shaped like an open fan, the ribs of which are simulated by the sash bars.

Circuit

Two or more wires that provide a path for electrical current from a source through some device using electric (such as a light) and back to the source.

Circuit Breaker

Automatic safety switch installed in a circuit to break the flow of electricity when the current exceeds a predetermined safe amount.  A safety device which opens (breaks) an electric circuit automatically when it becomes overloaded.

Clapboard

Exterior wood siding having one edge thicker than the other and laid so that the thick butt overlaps the edge of the board below.

Class A

The highest fire-resistance rating issued by Underwriters Laboratories (UL) for roofing. Indicates roofing is able to withstand severe exposure to fire originating from sources outside the building.

Class B

UL fire-resistance rating that indicates roofing material is able to withstand moderate exposure to fire originating from sources outside the building.

Class C

UL fire-resistance rating that indicates roofing material is able to withstand light exposure to fire originating from sources outside the building.