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 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. Radon gas 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. The rafters of a flat roof are sometimes called roof joists.
Rafter, Hip - A rafter that forms the intersection of an external roof angle.
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. 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).
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.
Raised Heel Roof Trusses - A raised heel truss adds an extension to the top of the exterior wall, allowing for the full depth of insulation to be applied.
Rake - Slope or slanted.
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 storey, one level home.
Range - Means a cooking appliance equipped with a cooking surface and 1 or more ovens.
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. Comes in various thickness' and strength grade.
Receptacle - An electrical outlet. A typical household will have many 120 volt receptacles for plugging in lams and 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.
Reducer Strip - Molding that finishes the space between wood or laminate flooring and other flooring surfaces, like vinyl or carpet.
Reflected Ceiling Plan - A reflected ceiling plan shows the ceiling as if you were lying on your back looking up, rather than the usual plan view.
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. Freon is an example and is used in air conditioning systems.
Register - A grill placed over a heating duct or cold air return.
Reglaze - To replace a broken window.
Relative Humidity - The amount of water vapour present in the air as a percentage of the amount, which would saturate it at the same temperature. For example, air containing one half the amount of moisture it is capable of holding has a relative humidity of 50%.
Relief Valve - A device designed to open if it detects excess temperature or pressure.
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.
Rendering - The art of shading or coloring a drawing.
Retaining Wall - A structure that holds back a slope and prevents erosion.
Retentions - Amounts withheld from progress billings until final and satisfactory project completion.
Return - The continuation of a molding or finish of any kind in a different direction.
Reveal - The distance measured from the trim surface of the jamb to the leading face of the door on the stop side when closed.
Ribbon - 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 Shingles - Shingles used to cover the ridge board.
Ridge Vent - A ventilator located at the ridge that allows the escape of warm and/or moist air from the attic area or rafter cavity.
Right Hand (Door) - Pertaining to an inward swinging door with hinges on the right side, using the outside of the door as reference.
Right Hand (Tub) - When you stand at the side of the tub, the drain is on the right.
Rim Joist - A joist that runs around the perimeter of the floor joists and home.
Ripping - Cutting of timber parallel to the grain
Rise - The vertical distance from the eaves line to the ridge. Also the vertical distance from stair tread to stair tread.
Riser (Carpentry) - Each of the vertical boards closing the spaces between the treads of stairways.
Riser (Plumbing) - A water distributing pipe that extends through at least one full storey. (as defined in Part 7 of the Ontario Building Code)
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.
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.
Roof Decking - The layer of wood or plywood applied directly to the rafters under the shingles.
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.
Rose - A trim plate attached to the door hardware behind the knob.
Rosette - A painted, carved, or sculptured ornament having a circular arrangement of parts radiating out from the center and suggesting the petals of a rose.
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. It is 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. See also Heat Rough, Plumbing Rough, and Electrical Rough.
Rough-In Dimensions - The distance from a finished wall or floor to the center of the waste or supply opening or mounting holes on a plumbing fixture.
ROXUL - ROXUL® products are mineral wool fibre insulations made from basalt rock and slag. This combination results in a noncombustible product with a melting point of approximately 2150°F (1177°C), which gives it excellent fire resistance properties. ROXUL mineral wool is a water repellent yet vapour permeable material.
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.
R Value - A measure of insulation. A measure of a materials resistance to the passage of heat. The higher the R-value, the better the building insulation's effectiveness.