A measure of a material's resistance to heat loss, usually applied to insulation products. The higher the R-value, the slower the rate of heat loss. …
Radiant Heating
A form of home heating delivered by electric-resistance elements--either wall registers or cables or foils beneath the flooring or above the ceiling--or via hot water circulated through in-the-floor …
Radon
A ground-generated radioactive gas that seeps into some homes through sump pumps, cracks in the foundation and other inlets. A serious health hazard. …
Rafter
One of a series of beams that form the slope of a pitched roof and are analogous to floor joists. …
Rails
The horizontal structural members of a door. Most doors have a top rail, a bottom rail, and a center rail connected at both ends to vertical stiles. …
Rammed-Earth Construction
An alternative building process in which dirt is compacted into large structural frames to create walls. …