- A measure of insulation. A measure of a materials resistance to the passage of heat. The higher the R value, the more insulating "power" it has. For example, typical new home's walls are usually insulated with 6" of batt insulation with an R value of R-21, and a ceiling insulation of R-49.

An enclosed channel designed to carry wires and cables.

The numerical value used to indicate the resistance to the flow of heat.

A method of heating, usually consisting of a forced hot water system with pipes placed in the floor, wall, or ceiling. Also electrically heated panels.

Heat transferred by radiation.

A rectangular longitudinal groove cut in the corner edge of a board or plank.

A measure of a materials resistance to the passage of heat. New home walls are usually insulated with 6" of batt insulation with an R value of R-21, and a ceiling insulation of R-49.

Forcing out of plumb of structural components, usually by wind, seismic stress or thermal expansion or contraction.

- Lumber used to support the roof sheeting and roof loads. Generally, 2 X 10's and 2 X 12's are used. The rafters of a flat roof are sometimes called roof joists. That member forming the slanting frame of a roof or top chord of a truss. Also known as hip, jack or valley rafter depending on its location and use.

A ventilation system beneath the floor of a basement and/or structural wood floor and designed to fan exhaust radon gas to the outside of the home

That part of a rafter that extends beyond the wall plate -- the overhang.

A naturally-occurring, heavier than air, radioactive gas common in many parts of the country. Radon gas exposure is associated with lung cancer. Mitigation measures may involve crawl space and basement venting and various forms of vapor barriers.

A rafter that forms the intersection of an internal roof angle. The valley rafter is normally made of double 2-inch-thick members.

A rafter that forms the intersection of an external roof angle.

- Black, tar and preservative impregnated, 6" X 8" and 6'-8' long wooden timber that was used to hold railroad track in place. Normally used as a member of a retaining wall.

Cross members of panel doors or of a sash. Also, a wall or open balustrade placed at the edge of a staircase, walkway bridge, or elevated surface to prevent people from falling off. Any relatively lightweight horizontal element, especially those found in fences (split rail).

Energy transmitted from a heat source to the air around it. Radiators actually depend more on convection than radiation. Transfer of heat energy through space by wave motion. Although the radiant energy of heat is transmitted through space, no heat is present until this energy strikes and is absorbed by an object. Not all of the radiant heat energy is absorbed; some is reflected to travel in a new direction until it strikes another object. The amount reflected depends on the nature of the surface that the energy strikes. This fact explains the principle of insulating foil and other similar products that depend on reflection of radiant heat for their insulating value. Radiant heat travels in straight lines in all directions at about the speed of light. In radiant heating systems, heat is often radiated down from the ceiling. As it strikes objects in the room, some is absorbed and some reflected to other objects. The heat that is absorbed warms the object, which, in turn, warms the surrounding air by conduction. This warmed air sets up gentle convection currents that circulate throughout the room.

The principle that states that wall cladding can be made watertight by placing wind-pressurized air chambers behind the joints, which reduces the air pressure differentials between the inside and outside that could cause water to move through the joints.

Concrete mixed at a plant or in trucks en route to a job and delivered ready for placement.

- A single story, one level home.