A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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.
Rafter– Lumber used to support the roof sheeting and roof loads. The rafters of a flat roof are sometimes called roof joists.
Rafter (Fixing Roof Tiles) – A structural member, usually timber, establishing the slope of the roof to, which the battens, counter battens, boards or underlay are fixed.
Rafter, hip– A rafter that forms the intersection of an external roof angle.
Rafter, top chord (Timber Roof Construction) – A horizontal or inclined member that establishes the upper edge of a truss (top chord).
Rafter, valley– A rafter that forms the intersection of an internal roof angle. The valley rafter is normally made of double 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).
Rake– Slope or slanted.
Rake fascia– The vertical face of the sloping end of a roof eave.
Raked flashing (Fixing Roof Tiles) – Cover flashing used at an inclined intersection, with its upper edge secured into a chase cut parallel to the top surface of roofing.
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.
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. Freon is an example and is used in air conditioning systems.
Registered person (Timber Roof Structures) – person who is registered with the Engineering Council of South Africa (ECSA).
Reglaze– To replace a broken window.
Reinforced masonry (Masonry) – Masonry in which grouted or concreted cavities, cores, or pockets or bed joints are reinforced with steel reinforcement to strengthen the masonry.
Reinforcement bond (Masonry) – The adhesion between steel reinforcement and mortar or infill concrete.
Relief valve– A device designed to open if it detects excess temperature or pressure.
Renovation – To restore to a previous or better condition.
Responsible person (Timber Roof Structures) – competent person who takes responsibility for designing, erecting, manufacturing or inspecting a timber roof structure.
Retaining wall– A structure that holds back a slope and prevents erosion.
Retempering (Cement plaster) – The addition of water and the remixing of a plaster mix, which has begun to stiffen.
Rib (Fixing Roof Tiles) – A longitudinal upstand in profiled sheeting, produced by forming or folding.
Ridge– The horizontal line at the junction of the top edges of two sloping roof surfaces.
Ridge (Fixing Roof Tiles) – The junction at the end of two roof slopes.
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.
Riser– Each of the vertical boards closing the spaces between the treads of stairways.
Rod reinforcement (Masonry) – Bed joint reinforcement in masonry, comprising hard drawn wires having a diameter of not less than 4.0mm or greater than 6,0mm which are pre-straightened at the point of manufacture.
Rodding eye (Drainage) – A permanent access opening, to the interior of a drainage installation, that permits full-bore access to the interior of a drain for cleaning, but does not include an inspection eye or manhole.
Roof (Fixing Roof Tiles) – Construction enclosing a building from above.
Roof joist– The rafters of a flat roof. Lumber used to support the roof sheeting and roof loads.
Roof valley– The “V” created where two sloping roofs meet.
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.
Runner (Timber Roof Structures) – (binder)-continuous bracing member that runs the length of the roof to provide lateral stability for web members or the chords of trusses in conjunction with triangulated cross-bracing.
Runner/Binder (Timber Roof Construction) – A continuous bracing member that runs the length of the roof to provide lateral stability for web members or chords of trusses in conjunction with triangulated cross bracing or other stiffener.