If a house has a fireplace, it is most often located in the living room or family room, although you might find a fireplace in a bedroom or kitchen. When inspecting the fireplace, look at the front face just above the firebox. If this area has a blackish tint or color, it is usually an indication of a smoky fireplace and is the result of a buildup over the years of layers of soot and creosote. This problem can usually be corrected.
A smoky fireplace might be the result of too small a flue for the size of the firebox opening. If this is the case, reducing the size of the opening by raising the hearth or installing a canopy on the top portion of the opening very often corrects the problem. However, determining the amount to raise the hearth or the size and shape of canopy to use requires experimentation. Sometimes the soot buildup is caused by backsmoking as a result of downdrafts. This is the result of wind currents bouncing off the side of the building or tall trees and then down the chimney. If the smoking is caused by downdrafts, the problem can usually be corrected by installing a concrete, stone, or metal cap on top of the chimney.
Backsmoking can also be caused by a negative pressure condition within the house. This is a fairly common phenomenon in newer houses. To conserve energy, newer homes are better caulked, weatherstripped, and tighter than older homes. The negative pressure results when more air in the house exhausts to the outside from fans, heating-system chimney, and so on than flows in from infiltration. Because of the negative pressure, when a fire is first lit in the fireplace and the damper is opened, there is an onrush of incoming air down the flue. This condition can be eliminated by slightly opening a window or in newer fireplaces opening the fresh-air vent associated with the fireplace.
Look inside the firebox for a damper. The damper is used to close the flue when the fireplace is not in use. It prevents heat loss through the flue in the winter and also prevents small animals such as squirrels and racoons from entering the room through the flue. Check the operation of the damper. On many older fireplaces, dampers were omitted. If the fireplace does not have a damper, or if the damper is defective, record that fact on your worksheet. A damper or equivalent is considered necessary, and one should be installed. If there is a chimney-top damper, check its operation. See chapter 3, page 22.
The bricks or stones lining the firebox should be checked for cracked, chipped, bro-ken, and disintegrating sections. Are the mortar joints intact, or are they in need of repointing? Cracked or open sections inside the firebox are a potential fire hazard and must be repaired.
Look up at the flue from inside the firebox. Normally this area will be coated with a layer of soot and creosote. If the layer is thick, have the chimney cleaned to minimize the possibility of a chimney fire. If the creosote layer is powdery, the flue can be cleaned by a chimney sweep with a brush. However, if the creosote buildup is of a tar consistency or a hard glaze, it cannot be brushed out by conventional means. It must be removed by chemical or mechanical means. Is there an obstruction in the flue, such as a bird’s nest? If the flue has a slight offset and you can see daylight, there is no obstruction. When the flue is offset so that you cannot see straight up, determining whether there is an obstruction is difficult without lighting a fire. One trick is to blow up at the flue to dislodge fine particles of soot. If the flue is not obstructed, they will float up the chimney.
In some homes you might find a prefabricated fireplace. These units are usually available with chimneys and have a specially insulated firebox shell. They are light in weight, do not require a special foundation, and can be wall-mounted or freestanding. The fireplace can be located in practically any part of a house, depending on local codes. If you find such a fireplace, check to see if it has been approved by Underwriters Laboratories, or some other nationally recognized testing agency.