R Value -A measure of insulation, or more specifically, a measure of a material's resistance to the passage of heat; the higher the R value, the better it insulates (e.g., the walls of a typical new home are usually insulated with 4" of batt insulation with an R value of R-13, and a ceiling insulation of R-30).
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; also refers to electrically heated panels.
Radiation - Energy transmitted from a heat source to the air around it; radiators actually depend more on convection than radiation.
Radon - A naturally-occurring, heavier than air, radioactive gas common in many parts of the country; exposure is associated with lung cancer; mitigation measures may involve crawl space and basement venting and various forms of vapor barriers.
Radon System - 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.
Rafter - Lumber used to support the roof sheeting and roof loads; generally, 2 X 10's and 2 X 12's are used; rafters of a flat roof are sometimes called roof joists
Rafter, Hip - A rafter that forms the intersection of an external roof angle.
Rafter Tail - The portion of a rafter that extends past the building to form the eaves.
Rafter, Valley - A rafter that forms the intersection of an internal roof angle; the valley rafter is normally made of double 2- inch-thick members.
Rail - Cross members of panel doors or of a sash; 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).
Railroad Tie - 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.
Rake - Slope or Slanted. Rake Edge. The overhang of an inclined roof plane beyond the vertical wall below it.
Rake Fascia - The vertical face of the sloping end of a roof eave.
Rake Siding - The practice of installing lap siding diagonally.
Ranch - A single story, one level home.
Random-tab Shingles - Shingles on which tabs vary in size and exposure.
Ready Mixed Concrete - Concrete mixed at a plant or in trucks en route to a job and delivered ready for placement.
Rebar, Reinforcing Bar - Ribbed steel bars installed in foundation concrete walls, footers, and poured in place concrete structures designed to strengthen concrete; available in various thickness and strength grades.
Receptacle - An electrical outlet; the typical household will have many 120-volt receptacles for appliances, and 240-volt receptacles for the range, clothes dryer, air conditioners, etc.
Recording Fee - A charge for recording the transfer of a property, paid to a city, county, or other appropriate branch of government.
Redline, Red Lined Prints - Blueprints that reflect changes and that are marked with red pencil.
Reducer - A fitting with different size openings at either end and used to go from a larger to a smaller pipe
Reflective Insulation -Sheet material with one or both faces covered with aluminum foil
Refrigerant - A substance that remains a gas at low temperatures and pressure and can be used to transfer heat (e.g.,Freon, used in air conditioning systems).
Register - A grill placed over a heating duct or cold air return.
Reglaze - To replace a broken window.
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 the temperature.
Release Tape - TA plastic or paper strip that is applied to the back of self-sealing shingles; prevents the shingles from sticking together in the bundles, and need not be removed for application.
Relief Valve - A device designed to open if it detects excess temperature or pressure.
Remodeling Contractor - A general contractor who specializes in remodeling work.
Remote - Remote electrical, gas, or water meter digital readouts that are installed near the front of the home in order for utility companies to easily read the home owners usage of the service.
Resilient Flooring - A durable floor cover that has the ability to resume its original shape.
Resorcinol Glue - A glue that is high in both wet and dry strength and resistant to high temperatures; used for gluing lumber or assembly joints that must withstand severe service conditions.
Retaining Wall - A structure that holds back a slope and prevents erosion.
Retentions - Amounts withheld from progress billings until final and satisfactory project completion.
Ribbon (girt) - Normally a 1 X 4 board let into the studs horizontally to support the ceiling or second-floor joists.
Ridge -The horizontal line at the junction of the top edges of two sloping roof surfaces.
Ridge Board - The board placed on the ridge of the roof onto which the upper ends of other rafters are fastened.
Ridge Cut - The end cut on a rafter that fits to the ridge board.
Ridge Shingles - Shingles used to cover the ridge board.
Rim Joist - A joist that runs around the perimeter of the floor joists and home.
Rise - The vertical distance from the eaves line to the ridge. Also the vertical distance from stair tread to stair tread (and not to exceed 7 ½").
Rise and Run - The angle of inclination or slope of a member or structure, expressed as the ration of the vertical rise to the horizontal run.
Riser - Each of the vertical boards closing the spaces between the treads of stairways.
Riser and Panel - The exterior vertical pipe (riser) and metal electric box (panel) the electrician provides and installs at the "Rough Electric" stage.
Road Base - A aggregate mixture of sand and stone.
Rock 1, 2, 3 - When referring to drywall, this means to install drywall to the walls and ceilings (with nails and screws), and before taping is performed.
Roll, Rolling - To install the floor joists or trusses in their correct place; to "roll the floor" means to install the floor joists.
Roll Roofing - Asphalt roofing products manufactured in roll form; 36-inch wide rolls with and 108 square feet of material; weights are generally 45 to 90 pounds per roll
Romex - - A popular name brand of nonmetallic sheathed electrical cable used for indoor wiring.
Roof Jack - Sleeves that fit around the black plumbing waste vent pipes at, and are nailed to, the roof sheeting.
Roof Joist - The rafters of a flat roof. Lumber used to support the roof sheeting and roof loads; generally, 2 X 10's and 2 X 12's are used.
Roof Sheathing or Sheeting - The wood panels or sheet material fastened to the roof rafters or trusses on which the shingle or other roof covering is laid.
Roof Valley - The "V" created where two sloping roofs meet.
Roofing Tape - An asphalt-saturated tape used with asphalt cements for flashing and patching asphalt roofing.
Rough Flooring - Materials used to form an unfinished floor; floor sheathing.
Rough Opening - The horizontal and vertical measurement of a window or door opening before drywall or siding is installed.
Rough Sill - The framing member at the bottom of a rough opening for a window; attached to the cripple studs below the rough opening.
Roughing-in - The initial stage of a plumbing, electrical, heating, carpentry, and/or other project, when all components that won't be seen after the second finishing phase are assembled.
Run, Roof - The horizontal distance from the eaves to a point directly under the ridge; one half the span.
Run, Stair - The horizontal distance of a stair tread from the nose to the riser.