Remodeling Terminology & Definitions · R

The following is a list of industry related terminology which we at The Remod Squad® thought might be helpful to both homeowners and professionals alike. Definitions will be continually added to this list.

r value

A measure of insulation, it's the thermal resistance to heat flow across a sample material of a unit area and known thickness caused by a temperature difference across it. This is often used to give a comparative value of the effect of different insulating materials. For example, typical new home's walls are usually insulated with 6" of batt insulation with an R value of R-19, and a ceiling insulation of R-28.

rabbet

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

radiant heating

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

rafter

One of a series of structural members of a roof designed to support roof loads. The rafters of a flat roof are sometimes called roof joists.

rail

Cross members of panel doors or of a sash. Also the upper and lower members of a balustrade or staircase extending from one vertical support, such as a post, to another.

rake

Trim members that run parallel to the roof slope and form the finish between the wall and a gable roof extension.

raw linseed oil

The crude product processed from flaxseed and usually without much subsequent treatment.

reflective insulation

Sheet material with one or both surfaces of comparatively low heat emissivity, such as aluminum foil. When used in building construction the surfaces face air spaces, reducing the radiation across the air space.

reinforcing

Steel rods or metal fabric placed in concrete slabs, beams, or columns to increase their strength.

relative humidity

The amount of water vapor in the atmosphere, expressed as a percentage of the maximum quantity that could be present at a given temperature. (The actual amount of water vapor that can be held in space increases with temperature.)

resorcinol glue

A glue that is high in both wet and dry strength and resistant to high temperatures. It is used for gluing lumber or assembly joints that must withstand severe service conditions.

ribbon (girt)

Normally a 1- by 4-inch board let into the studs horizontally to support ceiling or second-floor joists.

ridge

The horizontal line at the junction of the top edges of two sloping surfaces.

ridge board

The board placed on edge at the ridge of the roof into which the upper ends of the rafters are fastened.

rigid insulation board

A structural building board made of coarse wood or cane fiber in 1/2- and 25/32-inch thicknesses. It can be obtained in various size sheets, in various densities, and with several treatments.

rise

In stairs, the vertical height of a step or a flight of stairs.

riser

Each of the vertical boards closing the spaces between the treads of stairways.

roll roofing

Roofing material, composed of fiber and saturated with asphalt that is supplied in 36-inch wide rolls with 108 square feet of material. Weights are generally 45 to 90 pounds per roll.

roof sheathing

The boards or sheet material fastened to the roof rafters on which the shingle or other roof covering is laid.

rubber-emulsion paint

Paint, the vehicle of which consists of rubber or synthetic rubber dispersed in fine droplets in water.

run

In stairs, the net width of a step or the horizontal distance covered by a flight of stairs.