The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

How To Remodel Basements And Attics

Insulation

IT IS AN ESTABLISHED FACT that heat will flow through wood, brick, concrete, plaster and all other ordinary building materials. The flow of heat occurs whenever there is a difference in temperature between the two sides or surfaces of structural details such as walls, roofs and floors. In all cases, heat flows from high temperature to low temperature. That is, the direction of flow is always toward the lower temperature.

During cold weather the exterior surface of a wall, for example, has a much lower temperature than the interior surface. The exterior surface is chilled by the outdoor air whereas the interior surface is warmed by a heating system. Following the rule stated in the foregoing paragraph, the heat from the interior surface flows to the exterior surface and is lost to the great outdoors. When this happens, we say that heat loss has occurred.

During hot weather the exterior surface of a roof, for example, has a much higher temperature than the interior of the house. The roof is heated by the sun whereas the interior of the house is cooled by fans and other cooling devices. Following the rule stated previously, the heat from the roof flows into the house where it causes considerable discomfort. When this happens, we say that heat gain has occurred.

As explained in Chapter 6, insulation materials are made of substances that tend to prevent the flow of heat through them. If insulation is built into or installed in structural details such as walls, roofs and floors, the rate and amount of heat flow will be appreciably reduced.

It is safe to say that during cold weather up to 25 percent of the heat loss from an ordinary house occurs through the top-floor ceiling and the roof. It is also safe to say that during hot weather up to 35 percent of the heat gain occurs through the top-floor ceiling and the roof. Insulation is therefore a practical necessity in order to make attic spaces comfortable during both cold and hot weather.

WHERE INSULATION CAN BE USED

Fig. 1 shows a section view of a typical attic space that includes a shed dormer, a collar-beam ceiling, dormer walls, a knee wall and one portion of the ceiling directly under the rafters. The places where various kinds of insulation can be used are indicated.