Pacific Rainier Roofing Inc. - Roofing | Bothell, WA

Serving the Pacific Northwest | 425-771-4300

Benninger residence 2007 35 ton crane

Accelerated Weathering Testing - a method of exposing material to weathering elements in a controlled environment

Aggregate - small stone or rock used for roofing ballast

Alligatoring - cracks in the bitumen caused by UV rays and the loss of a protective coating. If left alone, the cracks can extend into the next layer.

Asbestos - was used in to reinforce roofing materials up until the 1980s

Asphalt (Bitumen) - a natural product used in road construction and roofing

Asphalt, Air Blown - asphalt produced by blowing air through molten asphalt to raise its softening point and modify other properties

Asphalt Emulsion - a mixture of asphalt particles and emulsifying agent such as bentonite clay and water

Back-Nailing - nailing and securing roofing layers in a way that they will be covered up by the next layer of roofing material

Ballast - loose gravel or stone used to hold a roofing membrane in place

Base Ply - the bottom layer of roofing

Bird Bath - a place where water pools on the roof

Bitumen - also called asphalt; it's a sticky and solid form of petroleum

Blackberry - a small bubble in the flood coating of a built-up roof membrane

Batt (Blanket) Insulation - fiberglass insulation that comes in a roll

Blocking - section of wood built into the roof to strengthen the deck or to provide a nailer for attaching a membrane or flashing

Boot - a flexible covering that protects against dirt and water

Bridging - an area of roofing that is unsupported by the deck

Brooming - the method of smoothing out a roofing ply into hot asphalt using a broom or squeegee

Buckle - a wrinkle in shingles or membrane

Built-Up Roof Membrane - multi-layered roofing with layers of bitumen and topped with aggregate

Butt Joint - a joint formed by two pieces of material placed end to end without overlapping

Butyl Tape - a putty-like adhesive used to make water tight seals especially with sheet metal joints

Canopy - a roofing hangover, usually over a door

Cant - a supporting strip placed under the roofing where it meets a right angle

Cap Flashing - usually metal that covers the upper edges of the roofing membrane

Capillary Action - the drawing of a liquid, often against gravity, into or up narrow interstices due to surface tension

Catalyst - a substance that increases the rate of a chemical reaction without being consumed in the process

Caulking - the process of making a water-tight seal with a filler

Cavity Wall - a space purposely built between two masonry walls for moisture control

Chalking - describes the appearance of paint that has deteriorated

Chlorinated Polyethylene (CPE) - a flexible, thermoplastic material used for single-ply roof membrane

Cladding - a weatherproof exterior covering of a building

Cleat or Clip - a metal strip used to secure roofing components

Closure Strip - a strip used mostly on corrugated metal to close up the ends to prevent water and animals from entering

Coal Tar Felt - felt that is saturated with coal tar

Coated Fabric - fabric impregnated or coated with plastic to be waterproof

Cold Process Built-up Roof - a roof membrane made up of layers of felts that are laminated with layers of roof adhesives or asphalt

Composition Shingle - asphalt shingle

Conditioning - the process of exposing material to the conditions they will be in once used for construction of the roof

Coping - the horizontal top surface that exposed to weather – often metal or masonry

Counterflashing - a strip of sheet metal in the form of an inverted L built into a vertical wall of masonry and bent down over the flashing to make it watertight

Course - the term for a row of shingles

Cove - an architectural member with a concave cross section

Cricket - an elevated structure meant to divert water around a chimney

Crystalline Waterproofing - a compound of chemicals, quartz sand and cement. It can enter the pores of concrete when wet and create a waterproof seal

Curb - a structure to support fans or ventilators

Cure - a finishing process caused by exposure to chemical, heat, or weather

Dead Level (Zero slope) - a flat roof area with no slope

Deck - the substrate that the roofing material is applied to

Degradation - decomposition due to exposure to harmful conditions

Delamination - separation of laminated layers

Drip Edge - an overhang meant to direct dripping water away from building components

Edge Stripping - the transition piece to seal the edges of the roofing material

Efflorescence - crystalline deposits formed on cement or masonry caused by moisture evaporation

Elastomeric Coating - a coating that enables the material to stretch to at least twice its length but allows it to return to its original size

Envelope (Bitumen-Stop) - a seal for preventing bitumen from leaking down into or off a building. Is constructed by extending the base sheet or other non-porous ply of felt beyond the edge of the field plies. It is then turned back onto the top of the system and adhered.

Expansion Joint - a built-in separation between building sections to allow for free movement between the sections without damaging the buildings structural components

Factory Seam - a seam made by the manufacturer using the assembly of the product

Fascia - a vertical band along the edge of the roof

Field of the Roof - the main part of the roof

Fishmouth - a term used to describe the end of a wrinkle in a seam

Flash Point - the lowest temperature at which material can vaporize to form an ignitable mixture in air

Flashing - material that seals the roof around protruding structures like chimneys

Glass Mat - a thin, reinforcing layer of a mat composed of glass fibers

Glaze Coat - the top layer of asphalt on a built-up roof membrane

Heat Welding - using hot air or open flame and pressure to seal and fuse roofing membranes

Hip Roof - roof that slopes upward from all sides of a structure having no vertical ends

Holiday - an area that is missing liquid-applied material

Infrared Thermography - a test that shows temperature of a roof to detect areas beneath the surface that may be wet

Kesternich Test - a simulation of acid rain conditions by subjecting test objects to a sulfur dioxide atmosphere as well as condensing moisture for the purpose of evaluating rust or corrosion characteristics

Knee Cap - a metal cover trim that fits over a panel rib after it has been cut and bent

Lap Seam - where overlapping materials are sealed or bonded

Loose-Laid Membranes - membranes that loose-laid, only attached at the edge of the roof and held down by ballast

Mansard Roof - a roof having two slopes on each side, the lower one having a steeper pitch than the upper; this increases the volume of the enclosed space

Mechanically Fastened Membranes - a roofing system with metal fasteners that penetrate the membrane and insulation to attach to the deck of the building

Membrane - a cover for flat or nearly flat roofs mainly for commercial use

Metal Flashing - sheet metal used to minimize water penetration around chimneys or other structures that penetrate the roof line

Moisture Relief Vent - a vent installed through the roofing membrane to relieve moisture vapor pressure that has been trapped within the roofing system

Moisture Scan - a survey to determine the amount of moisture in the roofing system

Mole Run - a meandering ridge in a roof membrane not associated with insulation or deck joints

Mopping - an application of molten asphalt to a roof

Mud Cracking - surface cracking resembling a dried mud flat

Ozone Resistance - the ability of a product to withstand deterioration by ozone

Permeability - the ability to allow liquid or gas to pass through a membrane

Picture Framing - a square or rectangular pattern of ridges in a roof membrane or covering over insulation or deck joints

Pipe Boot - a rubber seal where pipes protrude through the roof

Pitch-Pocket - a sheet metal sleeve flashed into the roofing membrane

Ponding - the unwanted pooling of water, typically on a flat roof

Positive Drainage - drainage within 48 hours following rainfall during conditions conducive to drying

Protected Membrane Roof - an insulated and ballasted roofing assembly in which the insulation and ballast are applied on top of the membrane

Rake - the sloped edge of a roof at or adjacent to the first or last rafter

Ridge - the highest point on a roof represented by a horizontal line where two roof areas intersect

Ridging - pattern of ridges

Rosin Paper - sometimes part of built-up roofs, the heavy-duty paper reduces air and moisture flow

Spalling - occurs when a substance sheds tiny particles of corrosion products

Substrate - surface upon which the roofing or waterproofing membrane is applied

Sump - roof sumps help the roof shed water more effectively and help eliminate the water pond size of flat roofs

Termination Bar - aluminum bar used to secure and seal the membrane on vertical or horizontal termination details

Thermal Shock - a sudden change in temperature can cause material to expand or contract rapidly and be damaged

Underlayment - a water-resistant or waterproof layer used beneath many types of roofing material

Wind Lift - occurs because of air pressure underneath the membrane and roof edges where it can cause the membrane to balloon and pull away from the deck

Woven Valley - shingle installation where the shingles from both sides of the roof valley extend over the valley and weave together overlapping courses alternately

Glossary Of Roofing Terms

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Roofing Terms Defined In Layman's Language