Glossary

Metal roofing, defined

227 plain-English definitions of the terms you'll meet while planning your last roof — each with a Washington application note covering Puget Sound winter rain and moss, Salish Sea salt air, Cascade snow load, and the region's housing stock.

General Concept

Camber: Camber is a slight upward curve or arch built into a roof, beam, or structural member to counteract anticipated deflection and ensure proper load distribution.
Capillary Action: Capillary Action is a physical phenomenon where water moves upward or laterally through narrow gaps or porous materials in roofing systems due to adhesive and cohesive forces, potentially leading to unintended moisture intrusion.
Chalk: Chalk is a fine, powdery substance used in roofing to mark straight lines or reference points on surfaces, typically applied with a chalk line tool for accurate layout and alignment during installation.; In Washington: Layout chalk washes off — worth noting only because on dark premium finishes we use low-stain chalk so a new Interlock roof isn't striped after its first install week.
Convection: Convection is a heat transfer process in roofing where warm air rises and cooler air sinks, creating air movement that affects temperature distribution within roof assemblies and attic spaces.
Energy Efficiency Federal Tax Credit: Energy Efficiency Federal Tax Credit is a government incentive that allows homeowners to claim a tax credit for installing qualifying energy-efficient roofing materials or systems that meet specific federal performance standards.
Roof Pitch: Roof Pitch is a measurement of a roof’s steepness, expressed as the ratio of its vertical rise to its horizontal span, which determines the angle and overall slope of the roof structure.
The Federal Investment Tax Credit (ITC): The Federal Investment Tax Credit (ITC) is a federal tax incentive that allows property owners to deduct a specified percentage of the cost of qualifying solar roofing systems from their federal income taxes.; In Washington: The federal ITC covers qualifying solar installs — relevant when pairing PV with a new aluminum roof so the roof never interrupts the array's payback period.
Transitions: Transitions is a roofing term referring to the areas where different roof planes, materials, or slopes meet, requiring specialized detailing to maintain structural integrity and weatherproofing at these junctions.
Urban Heat Island Effect: Urban Heat Island Effect is a phenomenon where urban areas, due to dense buildings, dark roofing materials, and limited vegetation, experience significantly higher temperatures than surrounding rural regions.
Vapor: Vapor is the gaseous form of moisture that can migrate through roofing assemblies, potentially leading to condensation within building envelope components if not properly managed.

Installation Method

Brake: Brake is a mechanical tool used in roofing and sheet metal work to bend, fold, or shape metal panels and flashings to precise angles and dimensions.
Bridging: Bridging is a structural technique in roofing where short, horizontal braces are installed between rafters or joists to maintain spacing, distribute loads, and enhance overall stability of the roof framework.
Butt Joint: Butt Joint is a connection where two roofing materials or components are placed end-to-end or edge-to-edge without overlapping, forming a straight seam at their adjoining surfaces.
Button Punch: Button Punch is a mechanical process in standing seam metal roofing where a tool crimps or indents overlapping panel seams to securely interlock them without additional fasteners.; In Washington: A standing-seam locking method; on our interlock systems the panel geometry itself provides the lock, with no field crimping to vary in quality.
Chalk line: Chalk line is a construction tool consisting of a string coated with chalk powder, used to mark straight, temporary reference lines on roofing surfaces for accurate alignment and layout during installation.
Closed Cut Valley: Closed Cut Valley is a roofing method where shingles from one roof slope are cut along the valley centerline and laid over continuous shingles from the adjacent slope, creating a clean, watertight intersection between two roof planes.
Concealed nail method: Concealed nail method is a roofing installation technique where nails are driven through the upper portion of each shingle or roofing unit and then covered by the next overlapping course, leaving fasteners hidden from view.; In Washington: Concealed fastening is standard on everything we install: exposed fasteners are the first failure point in freeze-thaw climates as gaskets age and back out.
Double coverage: Double coverage is a roofing method where each course of roofing material overlaps the preceding course by at least half its width, ensuring two layers of protection over the entire roof surface.; In Washington: A redundancy principle from the slate era that our four-way interlock preserves mechanically — every panel edge is locked under its neighbor, with no exposed horizontal seam anywhere on the field.
End Laps: End Laps is a roofing term referring to the overlapping joint formed where the ends of two roofing panels or sheets meet along their length, ensuring continuous coverage and weatherproofing at the panel junction.; In Washington: Every exposed end lap is a potential capillary path during freeze-thaw; our four-way interlock eliminates exposed field laps entirely.
Exposed nail method: Exposed nail method is a roofing installation technique where fasteners are driven through the surface of shingles or panels, leaving nail heads visible and directly exposed to weather elements.; In Washington: Exposed fasteners fail early in freeze-thaw climates — gaskets age, screws back out, and February meltwater finds every one. Nothing we install uses exposed field fastening.
Fastening Pattern: Fastening Pattern is a specified arrangement and spacing of fasteners, such as nails or screws, used to secure roofing materials to the roof deck according to structural requirements and manufacturer guidelines.
Nail Pattern: Nail Pattern is a specified arrangement and spacing of nails used to fasten roofing materials to the roof deck, ensuring structural integrity and compliance with manufacturer or code requirements.
Open valley: Open valley is a roof valley construction method where shingles are cut along both sides of the valley, leaving the metal flashing exposed to channel water off the roof.
Overlay Roofing: Overlay Roofing is a roofing method where a new layer of shingles or roofing material is installed directly over an existing roof without removing the original layer, maintaining the roof’s existing structure and geometry.
Roof Deck Preparation: Roof Deck Preparation is a process involving the inspection, cleaning, repair, and leveling of the structural surface to ensure it is suitable for the installation of roofing materials.
Tear-off: Tear-off is a roofing process that involves completely removing all existing roof materials down to the structural deck before installing a new roofing system.
Woven valley: Woven valley is a roofing technique where shingles from both intersecting roof slopes are alternately laced together across the valley, creating a continuous, interwoven covering without exposed metal or cut shingle edges.

Maintenance / Repair

Caulking: Caulking is a flexible sealing material applied to joints, seams, or gaps in roofing systems to prevent water, air, and debris infiltration by creating a weather-resistant barrier.

Organization / Standard / Code

Aluminum Association (AA): Aluminum Association (AA) is a standards organization that establishes specifications and designations for aluminum materials used in roofing and construction, ensuring uniformity in alloy composition, mechanical properties, and product identification.
American National Standards Institute (ANSI): American National Standards Institute (ANSI) is a private, non-profit organization that oversees the development and accreditation of consensus standards for products, services, processes, and systems in the roofing and construction industries.
American Society for Testing and Materials (ASTM): American Society for Testing and Materials (ASTM) is a globally recognized organization that develops and publishes technical standards for materials, products, systems, and services used in construction, including roofing systems.
ASHRAE: ASHRAE is a professional organization that develops standards and guidelines for heating, ventilation, air conditioning, refrigeration, and building energy efficiency, including those affecting roofing system design and performance.
Authority Having Jurisdiction (AHJ): Authority Having Jurisdiction (AHJ) is the official organization, office, or individual responsible for enforcing building codes, standards, and regulations on roofing projects within a specific geographic area or project scope.
Baeumler Approved: Baeumler Approved is a certification program that verifies contractors and home service companies meet specific professional, safety, and quality standards established by the Baeumler Approved organization.
Building Code: Building Code is a set of legally enforced regulations that specify minimum standards for the design, construction, alteration, and maintenance of buildings, including roofing systems, to ensure safety and structural integrity.
California Building Climate Zone: California Building Climate Zone is a geographic classification system used in California’s building codes to designate regions with similar climate conditions, guiding energy efficiency and construction requirements for roofing and other building systems.
Canadian Construction Materials Centre (CCMC): Canadian Construction Materials Centre (CCMC) is a national evaluation service in Canada that assesses and certifies construction materials, products, and systems for compliance with building codes and technical standards.
Canadian Roofing Contractors Association (CRCA): Canadian Roofing Contractors Association (CRCA) is a national trade organization in Canada representing roofing and related sheet metal contractors, establishing industry standards, technical guidelines, and best practices for roofing construction and maintenance.
Cool Roof Rating Council (CRRC): Cool Roof Rating Council (CRRC) is a nonprofit organization that develops and maintains objective standards for measuring and certifying the radiative properties—solar reflectance and thermal emittance—of roofing products.
Copper Development Association (CDA): Copper Development Association (CDA) is a technical trade organization that sets standards, provides resources, and promotes the proper use of copper and copper alloys in roofing and construction applications.
energy-efficiency Roofing: Energy Star Roofing is a roofing system or material that meets specific reflectivity and emissivity standards set by the U.S. Environmental Protection Agency to reduce heat absorption and improve energy efficiency.; In Washington: Interlock finishes were listed under the former ENERGY STAR roof program with initial solar reflectance up to 0.67; today the same performance is documented through CRRC-rated finish data relevant to MA and CT efficiency programs.
Environmental Protection Agency (EPA): Environmental Protection Agency (EPA) is a United States federal agency responsible for developing and enforcing regulations that protect human health and the environment, including standards for roofing materials and construction practices.
GuildQuality: GuildQuality is a third-party customer satisfaction surveying platform used by roofing and construction companies to collect, measure, and analyze client feedback on completed projects for quality assurance and performance tracking.
International Code Council (ICC): International Code Council (ICC) is a nonprofit organization that develops and publishes model building codes and standards, including those governing roofing systems, to ensure safety, quality, and regulatory compliance in construction.
Kynar 500: Kynar 500 is a high-performance polyvinylidene fluoride (PVDF) resin-based coating used on metal roofing panels to provide durable, long-lasting color retention and protection against weathering and environmental exposure.
Metal Construction Association (MCA): Metal Construction Association (MCA) is a trade organization that develops technical standards, resources, and advocacy for the use of metal materials in building envelope systems, including roofing, wall, and cladding applications.
Metal Roofing Alliance (MRA): Metal Roofing Alliance (MRA) is a trade association representing manufacturers and suppliers of residential metal roofing systems, providing technical resources, industry standards, and educational materials for metal roofing in North America.; In Washington: The residential metal-roofing trade body — we're members — whose consumer research consistently shows metal's share growing fastest in snow-country regions like ours.
National Research Council Canada (NRC): National Research Council Canada (NRC) is a Canadian government organization that develops and maintains technical standards, codes, and research for building science, including roofing systems and construction practices.
National Roofing Contractors Association (NRCA): National Roofing Contractors Association (NRCA) is a leading U.S. trade association representing roofing professionals, providing technical standards, education, and advocacy for the roofing industry’s practices, materials, and installation methods.
Occupational Safety and Health Administration (OSHA): Occupational Safety and Health Administration (OSHA) is a federal agency within the United States Department of Labor that sets and enforces standards for workplace safety and health, including construction and roofing environments.
UL (Underwriters Laboratories): UL (Underwriters Laboratories) is a globally recognized safety certification organization that tests and certifies roofing materials and assemblies for compliance with specific fire, wind, and impact resistance standards in the construction industry.

Performance Property

Abrasion resistance: Abrasion resistance is a material property that measures a roofing surface’s ability to withstand wear, scraping, or erosion caused by mechanical action, such as foot traffic, wind-blown debris, or equipment movement.
Absorption: Absorption is a process in roofing where a material takes in and retains moisture or liquid, typically measured as the percentage increase in weight after exposure to water under controlled conditions.
Accelerated weathering: Accelerated weathering is a laboratory testing process that simulates the long-term effects of environmental conditions such as sunlight, moisture, and temperature on roofing materials to evaluate their durability and performance.
Adhesion: Adhesion is the molecular attraction that causes roofing materials, such as membranes or coatings, to bond and remain attached to substrates or other surfaces within a roofing system.
Aged R-value: Aged R-value is a measurement of the long-term thermal resistance of roofing insulation, representing its insulating effectiveness after exposure to real-world aging factors such as heat, moisture, and time.
Aging: Aging is a process in which roofing materials deteriorate over time due to exposure to environmental factors such as sunlight, moisture, temperature fluctuations, and pollutants, leading to changes in physical and chemical properties.
Albedo: Albedo is a measure of a roofing material’s ability to reflect solar radiation from its surface, expressed as a ratio from 0 (no reflection) to 1 (total reflection).
Blow-Off Resistance: Blow-Off Resistance is a measure of a roofing system’s ability to withstand uplift forces from wind without components or materials being detached or displaced from the roof structure.; In Washington: Rated wind performance matters from the Cape to the Green Mountains: our interlocked panels are engineered for 120-mph wind warranty coverage, versus tab shingles that begin failing at highway speeds.
Class 4 impact resistance: Class 4 impact resistance is a roofing material rating indicating the highest level of durability against hail and debris impact, as tested under UL 2218 standards for structural integrity and surface protection.
Class A Fire Resistance: Class A Fire Resistance is a roofing classification indicating the highest level of fire protection, where the roof assembly can withstand severe fire exposure and resist flame spread according to standardized testing protocols.
Class B fire resistance: Class B fire resistance is a roofing classification indicating that the roof assembly can withstand moderate fire exposure and resist the spread of flames, as tested under standardized laboratory conditions.
Class C fire resistance: Class C fire resistance is a roofing classification indicating that the material can withstand light exposure to fire and slow flame spread, as tested under standardized laboratory conditions according to building codes.
Conduction: Conduction is a heat transfer process in roofing where thermal energy moves directly through solid materials, such as roof decking and insulation, from warmer to cooler areas without the movement of air or liquid.
Cool Roof: Cool Roof is a roofing system designed with materials or coatings that reflect more sunlight and absorb less heat than standard roofs, thereby reducing the roof surface temperature and thermal load on the building.
Cool-colored: Cool-colored is a roofing material or coating formulated with pigments that reflect more sunlight and absorb less heat than standard colors, regardless of the material’s visible shade.
Coverage: Coverage is a measurement in roofing that indicates the area a specific quantity of roofing material will effectively protect, typically expressed in square feet or squares, accounting for overlaps and waste.
Cross ventilation: Cross ventilation is a method of air movement in a building or roof structure achieved by strategically placing intake and exhaust openings on opposite sides to allow natural airflow across the space.
Exposure: Exposure is the portion of a roofing material, such as a shingle or tile, that is left uncovered and visible to the weather after installation, measured from the bottom edge to the exposed edge.; In Washington: Panel exposure is fixed by the interlock geometry, so a roof in Stowe reads as evenly coursed as one in Stonington — no installer-to-installer drift.
Heat Gain: Heat Gain is the increase in temperature within a building or roofing system caused by the absorption of solar radiation, conduction, and other external heat sources through the roof’s materials and structure.
Initial Solar Reflectance: Initial Solar Reflectance is a measurement of the fraction of solar energy that a new roofing surface reflects away from itself, expressed as a value between 0 and 1 under standardized testing conditions.
Initial Thermal Emittance: Initial Thermal Emittance is a measure of a roofing material’s ability to release absorbed heat as infrared radiation immediately after installation, expressed as a value between 0 and 1.
PVDF Coating: PVDF Coating is a high-performance fluoropolymer finish applied to metal roofing panels, consisting of polyvinylidene fluoride resin that provides a durable, chemically bonded protective layer against environmental exposure.
Solar Reflectance Index (SRI): Solar Reflectance Index (SRI) is a numerical measure that combines a roofing material’s solar reflectance and thermal emittance to indicate its ability to stay cool in sunlight.; In Washington: The combined reflectance-emittance score used by MA and CT efficiency programs; rated Interlock finishes provide documented SRI values for compliance paperwork.
Thermal Bridging: Thermal Bridging is a phenomenon where heat transfers through a roof or building envelope via materials with higher thermal conductivity, such as metal fasteners or framing, bypassing insulation and reducing overall energy efficiency.
Zero net energy: Zero net energy is a building design standard in which the total annual energy consumed by the structure, including its roofing system, is offset by on-site renewable energy generation, resulting in net zero energy use.

Problem / Defect

Algae discoloration: Algae discoloration is a staining or dark streaking on roofing surfaces caused by the growth of airborne algae, typically Gloeocapsa magma, which thrives in moist environments and feeds on roofing materials.
Alligatoring: Alligatoring is a roofing condition where the surface of asphalt-based materials develops a pattern of cracking that resembles alligator skin, caused by aging, UV exposure, and loss of flexibility in the material.
Blisters: Blisters is a roofing defect characterized by raised bubbles or pockets formed between roof membrane layers or between the membrane and substrate, caused by trapped air, moisture, or improper adhesion.
Blow-Offs: Blow-Offs is a roofing term referring to sections of roofing material, such as shingles or membranes, that are forcibly detached and removed from the roof structure by strong winds or severe weather conditions.
Buckling: Buckling is a structural deformation in roofing materials where the surface bends or warps out of plane, typically due to moisture, thermal movement, or improper installation, compromising the roof’s integrity.
Chalking: Chalking is a powdery residue that forms on the surface of roofing materials, such as coatings or membranes, due to the degradation of binders from prolonged exposure to ultraviolet (UV) radiation and weathering.
Condensation: Condensation is a process where water vapor in the air changes into liquid water upon contacting cooler surfaces within a roofing system, potentially leading to moisture accumulation and related structural issues.
Granule Loss: Granule Loss is a condition where the protective mineral granules on the surface of asphalt shingles detach and erode, exposing the underlying bitumen layer to weathering and potential damage.
Ice Dam: Ice Dam is a ridge of ice that forms along the edge of a roof when melting snow refreezes, preventing proper drainage and causing water to back up under roofing materials.
Oil canning: Oil canning is a visible waviness or distortion in the flat surfaces of metal roofing or wall panels, caused by stress, improper installation, or thermal expansion affecting the panel’s geometry.
Tented: Tented is a roofing condition where the roofing membrane or material is raised or lifted away from the substrate, forming a tent-like shape due to trapped moisture, air, or improper installation.

Roof Component

Apron Flashing: Apron Flashing is a flat or angled strip of metal installed at the intersection where a roof meets a vertical surface, such as a wall or chimney, to direct water away from the joint.
Attic: Attic is a space or room located directly below the pitched roof of a building, enclosed by the roof structure and exterior walls, often used for storage or housing mechanical systems.
Attic vent: Attic vent is a roof or gable-mounted opening or device designed to allow air to flow into or out of an attic space, facilitating passive ventilation of the building envelope.
Barge board: Barge board is a board or trim fixed to the projecting gable end of a pitched roof, covering and protecting the roof timbers and providing a finished edge along the roofline.
Base flashing: Base flashing is a strip of waterproof material installed at the joint where a roof surface meets a vertical wall or projection, directing water away from the intersection to prevent leaks.
Batten: Batten is a thin, narrow strip of wood, metal, or plastic installed horizontally or vertically on a roof structure to provide a fixing point for roofing materials such as tiles, slates, or shingles.
Bird stop: Bird stop is a metal or plastic barrier installed at the eaves or ridges of tile roofs to block gaps and prevent birds or debris from entering beneath the roofing tiles.
Boot: Boot is a pre-formed, waterproof flashing component designed to seal around roof penetrations such as vent pipes, preventing water intrusion at the point where the pipe passes through the roofing material.
Butt edge: Butt edge is the lower, exposed edge of a roofing shingle that is visible once installed and forms the bottom line of each shingle course on a roof.
Canopy: Canopy is a projecting roof structure, typically attached to a building’s exterior, designed to provide shelter or shade over entrances, walkways, or loading areas without enclosing the space beneath.
Cant: Cant is a beveled or angled strip of material installed at the junction of a flat roof and a vertical surface to create a smooth transition and reduce sharp angles.
Cap Flashing: Cap Flashing is a protective metal covering installed over the top edge of base flashing or masonry walls to prevent water infiltration at roof and wall intersections.
Cavity wall: Cavity wall is a type of wall construction consisting of two parallel masonry walls separated by an air space or cavity, designed to improve insulation and prevent moisture penetration in buildings.
Chimney: Chimney is a vertical masonry or metal structure that extends above the roofline to safely vent smoke, gases, and combustion byproducts from fireplaces, stoves, or furnaces to the outside atmosphere.
Chimney collar: Chimney collar is a sheet metal flashing installed around the base of a chimney where it penetrates the roof, forming a waterproof seal between the chimney and roofing materials to prevent water intrusion.
Cladding: Cladding is a protective external layer or covering applied to a building’s roof or walls to shield the underlying structure from weather and environmental elements.
Cleat: Cleat is a strip of metal or wood fastened to a roof structure to secure, support, or connect roofing components such as flashings, panels, or tiles in place.
Collar: Collar is a horizontal timber or metal member fixed between opposing rafters in a pitched roof, typically in the upper third of the roof span, to provide structural stability and resist rafter spread.
Counter Flashing: Counter Flashing is a secondary layer of metal or other waterproof material installed over base flashing at roof joints, chimneys, or walls to prevent water infiltration by directing runoff away from vulnerable seams.
Course: Course is a continuous horizontal row of roofing materials, such as shingles, tiles, or slates, installed parallel to the eaves or ridge to form a uniform layer across the roof surface.
Cover board: Cover board is a rigid, thin material layer installed between the roof insulation and membrane in low-slope roofing systems to provide a stable, smooth substrate and enhance the roof assembly’s structural integrity.; In Washington: Flat-roof component for the region's low-slope sections; steep-slope aluminum needs only sound sheathing and underlayment.
Crickets: Crickets is a small, peaked or sloped structure installed on the high side of a roof feature, such as a chimney or skylight, to divert water around the obstruction and prevent ponding.
Cupola: Cupola is a small, dome-like or polygonal structure mounted on a roof or dome, often featuring windows or louvers, that provides ventilation, natural light, or architectural accent to a building.
Cutout: Cutout is a slot or open section in a strip shingle, typically rectangular, that separates individual tabs and creates the appearance of multiple smaller shingles on a roof.
Deck: Deck is a structural surface, typically made of wood, metal, or concrete, that forms the base layer of a roof system and supports the roofing materials above.
Dormer: Dormer is a roofed structure that projects vertically from a sloping roof, typically containing a window, and is integrated into the roof’s plane to provide additional headroom and natural light.
Downspout: Downspout is a vertical pipe attached to the exterior of a building that channels rainwater from the roof gutter system down to the ground or designated drainage area.
Downspout Diverter: Downspout Diverter is a plumbing device installed in a roof drainage system that redirects water flow from a downspout to an alternate location, such as a rain barrel or garden, instead of directly to the ground or sewer.; In Washington: Popular with rain-barrel users in eco-minded VT and MA towns; clean aluminum-roof runoff (no granules, no algae treatment) is well suited to garden collection.
Drip Edge: Drip Edge is a metal flashing installed along the edges of a roof to direct water away from the fascia and underlying roofing components, protecting the roof’s structure from moisture intrusion.
Eave: Eave is the lower edge of a roof that projects beyond the exterior wall, forming an overhang that directs water away from the building’s walls and foundation.
Eave Flashing: Eave Flashing is a strip of waterproof material installed along the lower edge of a roof at the eaves to direct water away from the roof deck and prevent moisture intrusion at this vulnerable junction.
Fascia: Fascia is a horizontal board mounted at the edge of a roof, typically attached to the ends of rafters or trusses, serving as a finishing trim and supporting the lower edge of the roof covering.
Fasteners: Fasteners is a category of mechanical devices, such as nails, screws, or bolts, used to securely attach roofing materials to the structural deck or framework of a roof system.; In Washington: Every fastener we drive is concealed and corrosion-matched to aluminum — mixed metals plus coastal salt air is a galvanic failure waiting to happen.
Field of Roof: Field of Roof is the main, continuous expanse of a roof surface located between the perimeter edges, ridges, hips, and valleys, excluding any penetrations, flashings, or special detailing areas.; In Washington: On our systems the field is a continuous interlocked membrane — the reason wide-open Cape and ranch roof planes survive gusts that strip tab shingles.
Flashing: Flashing is a thin, impervious material installed at roof joints, edges, or penetrations to direct water away from seams and prevent moisture intrusion into the building envelope.
Gutter Guard: Gutter Guard is a protective covering or insert made from mesh, foam, or solid materials that is installed over or inside roof gutters to physically block debris while allowing water to flow through the drainage system.
Hip: Hip is a sloped external angle formed by the intersection of two roof planes, running from the eaves to the ridge, which creates a prominent diagonal seam on a hip roof structure.; In Washington: Hips take the brunt of coastal gusts; our hip caps lock mechanically to the panel field rather than relying on exposed fasteners that wind works loose.
Hip Legs: Hip Legs is a term referring to the sloping external edges or rafters that run from the ridge to the eaves at the corners of a hip roof, forming the intersection between adjacent roof slopes.
Ice and Water Shield: Ice and Water Shield is a self-adhering, waterproof membrane installed on roof decks to create a continuous barrier that prevents water infiltration from ice dams and wind-driven rain.
L Flashing: L Flashing is a metal flashing shaped like an "L" that is installed at roof-to-wall intersections to direct water away from the joint and prevent moisture intrusion.
Mokoshi: Mokoshi is a decorative pent roof or skirt roof in traditional Japanese architecture, built around the exterior of a building below the main roof to create the appearance of an additional story.; In Washington: Japanese architectural term kept for reference.
Outshot: Outshot is a roof extension projecting from the main roof slope, typically covering an addition such as a lean-to or rear wing, with its own lower roofline integrated into the primary structure.
Perimeter Zone: Perimeter Zone is a designated area along the outer edges of a roof where wind pressures are typically higher, requiring specific design and attachment methods to ensure structural integrity and code compliance.
Pipe Boot Flashing: Pipe Boot Flashing is a pre-formed, waterproof roofing component designed to seal around pipes or vents that penetrate the roof surface, preventing water intrusion at these vulnerable junctions.
Radiant Barrier: Radiant Barrier is a reflective material installed in roofing assemblies to reduce heat transfer by reflecting radiant energy, typically consisting of a thin layer of aluminum foil applied to one or both sides of a substrate.
Rainwater Harvesting System: Rainwater Harvesting System is a roof-integrated assembly of gutters, downspouts, filters, and storage tanks designed to collect, convey, and store rainwater runoff from building surfaces for non-potable use or controlled discharge.
Rake edge: Rake edge is the sloped edge of a roof that runs from the eave to the ridge along the gable end, forming the outer perimeter of a pitched roof’s inclined sides.
Ridge Vent: Ridge Vent is a continuous, low-profile ventilation component installed along the peak of a sloped roof, designed to allow warm, humid air to escape from the attic or roof cavity.
Roof Curb: Roof Curb is a raised, framed structure installed on a roof surface to provide a level mounting platform and weatherproof support for equipment such as HVAC units, skylights, or exhaust fans.
Roof Drain: Roof Drain is a plumbing fixture installed on flat or low-slope roofs to collect and channel rainwater or melted snow from the roof surface into the building’s internal drainage system.
Roof Hatch: Roof Hatch is a horizontal, hinged access door installed in a roof structure, allowing safe entry and exit between the building interior and the rooftop for maintenance or emergency purposes.
Roof Louvers: Roof Louvers is a type of fixed, slatted vent installed on the roof surface that allows for passive ventilation of attic spaces by permitting air flow while preventing water and debris intrusion.; In Washington: Box vents work, but in snow country they can be buried by drift; ridge-and-soffit systems ventilate below the snow line instead.
Roof Penetration: Roof Penetration is an opening or projection through a roof surface, such as for vents, pipes, skylights, or HVAC units, that interrupts the roof’s continuous structure and requires specialized flashing or sealing.; In Washington: Every stack, skylight, and solar standoff is a hole in the region's freeze-thaw armor; our penetration details pair membrane with formed metal — no caulk-dependent shortcuts.
Roof Plane: Roof Plane is a flat or sloped surface of a roof, defined by its boundaries and pitch, that extends between the roof’s edges, ridges, hips, or valleys to form the overall roof structure.
Scupper: Scupper is a drainage opening in the edge of a flat or low-slope roof or parapet wall that allows water to flow off the roof surface and away from the building structure.
Sealant Strip: Sealant Strip is a narrow adhesive band applied to roofing components, such as shingle undersides or laps, designed to create a watertight seal and prevent moisture or wind infiltration at joints or overlaps.
Side walls: Side walls is a term in roofing that refers to the vertical exterior walls of a building where the sloped roof surface meets or intersects the wall, typically requiring flashing to prevent water intrusion.; In Washington: Where dormers and second stories meet roof planes — prime ice-dam leak territory. Step flashing woven into the panel field, plus membrane, protects these junctions.
Skylight Flashing Kit: Skylight Flashing Kit is a prefabricated set of metal or composite components designed to seal the intersection between a skylight and the roof surface, preventing water infiltration at the skylight opening.; In Washington: Manufacturer kits assume asphalt; on our installs skylights get custom-formed aluminum flashing integrated with the interlock field — built for drifted snow and ponding meltwater.
Snow guards: Snow guards is a type of rooftop device, typically made of metal or polycarbonate, installed on sloped roofs to mechanically hold and control the movement of snow and ice.
Snow rails: Snow rails is a type of rooftop barrier system consisting of horizontal metal bars or rails installed near the eaves to retain and control the movement of accumulated snow on sloped roofs.
Snow Retention System: Snow Retention System is a roof-mounted assembly of devices or barriers designed to control the movement of snow and ice on sloped roofs, preventing sudden sliding or shedding.
Soffit ventilation: Soffit ventilation is a system of intake vents installed in the underside of a roof’s overhang (soffit) that allows outside air to enter the attic or roof cavity for proper airflow.
Soffits: Soffits is the horizontal or sloped underside of a roof overhang or eave, enclosing the space between the roof edge and the exterior wall to protect rafters and provide ventilation.
Solar Tube: Solar Tube is a tubular daylighting device installed through a roof that channels natural sunlight from the exterior into interior spaces using a reflective, sealed tube and a rooftop dome.
Starter strip: Starter strip is a pre-cut or roll roofing material installed along the eaves or rakes of a roof to provide a secure, straight edge and proper shingle alignment for the first course of shingles.
Step flashing: Step flashing is a series of overlapping, L-shaped metal pieces installed at roof-to-wall intersections to direct water away from seams and prevent leaks where the roof meets vertical surfaces.
Substrate: Substrate is the underlying structural surface or layer of a roof, such as decking or sheathing, to which roofing materials are applied and secured during installation.
Tubular Skylight: Tubular Skylight is a cylindrical daylighting device installed through a roof, consisting of a reflective tube that channels natural light from a rooftop dome to an interior ceiling diffuser.; In Washington: See solar tube — a favorite daylighting retrofit in the region's center-hall Colonials.
Underlayment: Underlayments is a layer of material installed directly onto a roof deck beneath the primary roofing covering, serving as a secondary barrier to protect the structure from water infiltration and environmental elements.
Valley: Valley is a linear, internal angle formed where two sloping roof planes intersect, channeling water runoff along its trough to the roof’s drainage system.
Vapor retarder: Vapor retarder is a material or membrane installed within a roofing system to limit the passage of water vapor through the roof assembly, thereby controlling moisture migration into building components.
Vent sleeve: Vent sleeve is a cylindrical or conical flashing component installed around roof penetrations, such as vent pipes, to provide a watertight seal and protect the roof assembly from moisture intrusion.
Warm wall: Warm wall is a wall construction method where all insulation is placed on the exterior side of the structural wall, keeping the wall structure within the building’s thermal envelope and above the dew point temperature.

Roof Type

A-frame: A-frame is a roof structure characterized by steeply angled sides that meet at the top in the shape of the letter "A," forming a triangular silhouette that extends to the building’s foundation.
Barrel roof: Barrel roof is a curved roofing structure with a semi-cylindrical shape resembling a barrel cut lengthwise, typically spanning large spaces without internal supports and often constructed from materials like metal, concrete, or wood.
Bonnet roof: Bonnet roof is a dual-pitched roof design featuring two slopes on each side, with the lower slope set at a gentler angle and extending outward beyond the walls to form overhanging eaves.
Butterfly roof: Butterfly roof is a V-shaped roof structure formed by two roof surfaces sloping inward toward a central valley, creating an inverted gable that resembles the wings of a butterfly.
Clerestory roof: Clerestory roof is a roof design featuring a raised section with vertical windows or openings above adjoining lower rooflines, allowing natural light to enter the interior space below.
Cross gabled: Cross gabled is a roof design where two or more gable roof sections intersect at right angles, creating a structure with multiple ridges and distinct, perpendicular rooflines.
Cross hipped: Cross hipped is a roof design where two or more hipped roof sections intersect at right angles, forming an L- or T-shaped structure with hips running along the junctions.; In Washington: Cross-hipped roofs on the region's four-squares and newer builds spread snow well but multiply hip and valley lines — a strength of panel-by-panel metal installation.
Dormer roof: Dormer roof is a roof structure that projects vertically from a sloping main roof, typically containing a window, to create additional headroom and usable space within the roof area.; In Washington: Shed and gable dormer roofs collect drifting snow against the main roof plane; their junctions get ice-and-water membrane plus formed metal flashing on our installs.
Dutch gable roof: Dutch gable roof is a hybrid roof structure that combines a traditional gable roof with a hip roof, featuring a small gable at the peak of a hipped end for added attic space and architectural detail.
East Asian hip-and-gable roof: East Asian hip-and-gable roof is a traditional roof structure featuring a central gabled section flanked by hipped slopes on all sides, commonly seen in Chinese, Japanese, and Korean architecture.
Flat roof: Flat roof is a roof structure characterized by a nearly horizontal or low-slope surface, typically with a pitch of 10 degrees or less, designed to efficiently shed water and support roofing membranes.
Gable roof: Gable roof is a roof structure featuring two sloping sides that meet at a central ridge, forming a triangular end wall known as a gable at each end of the building.
Gambrel roof: Gambrel roof is a two-sided roof design featuring two slopes on each side, with the lower slope steeper than the upper, creating a profile often seen on barns and colonial-style buildings.; In Washington: The Yankee barn profile, common on Dutch Colonials across MA and CT; the pitch break demands a transition detail that panel systems handle crisply — and the steep lower slope shows off premium finishes.
Half-hipped: Half-hipped is a roof type where the end of a gable roof is partially sloped down, creating a truncated hip at the top while retaining a short vertical section below.; In Washington: The jerkinhead's cousin, seen across the region's older housing; clipped-gable transitions are formed metal territory.
Hidden roof: Hidden roof is a roof structure where the main roof slopes are concealed behind parapet walls or facade elements, making the roofline invisible from the exterior and creating a flat or uniform building profile.
Hip and valley roof: Hip and valley roof is a complex roof structure featuring intersecting hips and valleys formed where two roof sections meet at different angles, creating multiple slopes that direct water away from the roof’s intersections.
Hip Roof: Hip Roof is a roof type where all sides slope downward to the walls, typically with a gentle pitch, forming a consistent eave around the structure and lacking vertical gable ends.
Jerkinhead roof: Jerkinhead roof is a hybrid roof style where the gable ends are clipped or truncated with a short hip, creating a roof that combines elements of both gable and hip roof structures.
Karahafu: Karahafu is a distinctive Japanese roof gable featuring an undulating, curved bargeboard profile, typically used in traditional architecture to create an elegant, wave-like outline above entrances or important structures.
Low Slopes: Low Slopes is a roofing term describing roof surfaces with a pitch between 2:12 and 4:12, where the vertical rise is minimal relative to the horizontal run, requiring specialized waterproofing systems.
Mansard roof: Mansard roof is a four-sided, dual-pitched roof characterized by two slopes on each side, with the lower slope being steeper and often punctuated by dormer windows, creating additional attic or living space.
Monitor roof: Monitor roof is a roof structure featuring a raised central section with its own roof and vertical sides, typically containing windows or louvers, running along the ridge of a larger roof for added light or ventilation.
Mono-pitched roof: Mono-pitched roof is a single-sloped roof structure consisting of one flat surface set at an angle, typically spanning from one wall to another, without any intersecting or opposing roof planes.
Pyatthat: Pyatthat is a tiered, multi-roofed structure in Burmese architecture, characterized by a series of progressively smaller, stacked roofs with ornate spires, typically crowning temples, palaces, or significant religious buildings.; In Washington: Burmese architectural term kept for reference.
Pyramid roof: Pyramid roof is a type of hipped roof with four identical triangular sides that slope upward from each building corner to meet at a single point at the top, forming a pyramid-like structure.
Saltbox roof: Saltbox roof is a pitched roof design featuring two asymmetrical slopes, with one long, low slope and one short, steep slope, creating an uneven profile typically used in traditional colonial architecture.
Saw-tooth roof: Saw-tooth roof is a roof design featuring a series of parallel, vertical or near-vertical surfaces alternating with sloped surfaces, resembling the teeth of a saw, typically used to maximize natural light in industrial buildings.
Shed roof: Shed roof is a single-sloped roof structure with one flat surface that slopes in one direction, typically attached to a taller wall, commonly used for additions, porches, or simple buildings.
Skillion roof: Skillion roof is a single-sloped roof structure featuring one flat surface set at an angle, without ridges or peaks, typically used for modern residential, commercial, or outbuilding designs.; In Washington: The contemporary single-slope profile appearing in VT and coastal builds; one plane, fast shedding, clean panel lines.
Steep-slope roofing: Steep-slope roofing is a roofing system installed on structures with a roof pitch greater than 3:12, characterized by sharply angled surfaces that facilitate rapid water runoff.
Terrace: Terrace is a flat, horizontal roof or platform, often constructed above a building or part of a building, designed to provide an accessible outdoor space for various uses.

Roofing Material

3-tab shingle: 3-tab shingle is a type of asphalt roofing material featuring a flat, rectangular design with three evenly spaced cutouts along the lower edge, creating the appearance of three separate shingles per strip.
Acrylic resin: Acrylic resin is a synthetic polymer material used in roofing systems as a base for coatings and sealants, providing a durable, flexible, and UV-resistant protective layer on various roof surfaces.
Adhesive: Adhesive is a bonding agent used in roofing systems to securely attach membranes, insulation, or other materials to substrates, ensuring structural integrity and weather resistance without mechanical fasteners.
Aluminum: Aluminum is a lightweight, corrosion-resistant metal used in roofing systems as panels, shingles, or flashing to provide durable, weatherproof coverage and structural protection for buildings.
Architectural Shingles: Architectural Shingles is a type of asphalt roofing material composed of multiple laminated layers, designed to create a dimensional, contoured appearance that mimics the look of traditional wood or slate shingles.
Asphalt: Asphalt is a black, sticky, semi-solid form of petroleum used as a waterproofing and binding agent in roofing systems, typically applied as shingles or built-up roofing membranes.
Asphalt Primer: Asphalt Primer is a liquid bituminous coating applied to prepared surfaces such as concrete, metal, or wood to promote adhesion of asphalt-based roofing materials and ensure proper bonding during roof system installation.
Asphalt roof cement: Asphalt roof cement is a thick, bituminous compound used to seal, bond, and waterproof joints, flashings, and repairs on asphalt-based roofing systems.
Asphalt Shingles: Asphalt Shingles is a type of overlapping, rectangular roofing material composed of a fiberglass or organic mat coated with asphalt and mineral granules, designed to form a watertight, weather-resistant roof covering.
Back surfacing: Back surfacing is a layer of fine mineral material applied to the underside of asphalt roofing shingles or rolls to prevent sticking during storage and handling.
Ballast: Ballast is a layer of heavy material, such as gravel or concrete pavers, placed on flat or low-slope roofing membranes to hold them in place and protect against wind uplift.
Base sheet: Base sheet is a foundational layer of roofing material, typically made of asphalt-impregnated felt or fiberglass, installed directly over the roof deck to provide a substrate for additional membrane layers in built-up or modified bitumen roofing systems.
Base-ply sheet: Base-ply sheet is a foundational layer of roofing membrane, typically made from asphalt-saturated or modified bitumen material, installed directly over the roof deck to provide structural support in multi-ply roof systems.
Bitumen roofing: Bitumen roofing is a flat or low-slope roofing system composed of layers of asphalt-based bitumen, reinforced with materials like fiberglass or polyester, and applied as built-up roofing (BUR) or modified bitumen membranes.
Bundle: Bundle is a packaged unit of roofing materials, such as shingles or shakes, that is wrapped and bound together for transport and installation, typically containing a specific quantity to cover a defined roof area.
Cap sheet: Cap sheet is a flexible, reinforced membrane layer installed as the top surface of a multi-ply low-slope or flat roofing system, typically composed of bitumen and embedded mineral granules for weather protection.
Clay Roof Tiles: Clay Roof Tiles is a type of roofing material made from molded and kiln-fired natural clay, designed in interlocking or overlapping shapes to form a durable, water-shedding covering for pitched roofs.
Coated base sheet: Coated base sheet is a roofing membrane consisting of a fiberglass or organic mat saturated and coated with asphalt or modified bitumen, serving as a foundational ply in built-up or modified bitumen roof systems.
Concrete Roof Tiles: Concrete Roof Tiles is a type of roofing material made from molded Portland cement, sand, and water, formed into interlocking or overlapping units designed to shed water and protect building structures.
Cool roof shingle: Cool roof shingle is a type of roofing shingle engineered with highly reflective materials or coatings to reduce heat absorption by reflecting more sunlight than standard shingles.
DuraPON 70: DuraPON 70 is a high-performance, two-component polyurethane roof coating system designed to provide a seamless, waterproof, and UV-resistant protective membrane for various commercial and industrial roofing substrates.
EPDM rubber: EPDM rubber is a synthetic, single-ply roofing membrane made from ethylene propylene diene monomer, designed for waterproofing flat or low-slope roofs in commercial and residential construction.
Granules: Granules is a layer of small, mineral-coated particles embedded on the surface of asphalt shingles to provide physical protection and color to the roofing material.
Modified bitumen: Modified bitumen is a type of multi-layered, asphalt-based roofing membrane reinforced with polymers and installed in sheets, designed for low-slope or flat roof assemblies to provide waterproofing and structural protection.
Oriented Strand Board (OSB): Oriented Strand Board (OSB) is a structural engineered wood panel made by compressing layers of wood strands arranged in specific orientations and bonded with adhesives, commonly used as roof decking and sheathing.
PVC roofing: PVC roofing is a single-ply roofing membrane made from polyvinyl chloride, designed for flat or low-slope roofs, and installed in sheets that are heat-welded to form a continuous, waterproof barrier.
Solar Shingles: Solar Shingles is a type of roofing material composed of photovoltaic cells integrated into shingle-shaped modules designed to function as both a weatherproof roof covering and a solar energy generator.; In Washington: Integrated PV is emerging in solar-friendly MA and VT; the pragmatic path today is rated rooftop PV mounted on a permanent aluminum roof that outlives the array.
Stone coated steel roofing: Stone coated steel roofing is a type of roofing system composed of formed steel panels coated with a layer of stone granules, designed to mimic traditional roofing materials while providing structural durability and weather resistance.; In Washington: Steel with a granule coat — but steel rusts at scratches and cut edges, a real liability in coastal salt air, and the granules that make it look like asphalt also age like asphalt. Aluminum needs neither galvanizing nor granules.
Synthetic roofing: Synthetic roofing is a type of roofing system composed of engineered materials such as polymers, rubber, or plastic composites designed to replicate the appearance and function of traditional roofing materials like slate, wood, or tile.
Synthetic Underlayment: Synthetic Underlayment is a manufactured roofing membrane made from engineered polymers, installed beneath the primary roof covering to provide a water-resistant barrier and protect the roof deck from moisture intrusion.
TPO Roofing: TPO Roofing is a single-ply roofing membrane system made from thermoplastic polyolefin, installed in sheets and heat-welded at the seams to form a continuous, waterproof barrier on flat or low-slope roofs.
Wood shakes: Wood shakes is a type of roofing material made from split logs, typically cedar, cut into irregular, thick, and textured pieces that are installed in overlapping rows to form a weather-resistant roof covering.
Wood shingles: Wood shingles is a roofing material consisting of thin, tapered pieces of natural wood that are laid in overlapping rows to form a weather-resistant, sloped roof covering.

Roofing System / Assembly

BIPV: BIPV is a roofing system where photovoltaic materials are integrated directly into the building envelope, such as roof tiles or shingles, to serve as both a weather barrier and a source of solar power.; In Washington: Building-integrated PV is growing in MA and VT thanks to strong state solar incentives; a permanent aluminum roof is the logical substrate, since it will outlast the panels rather than needing replacement mid-array.
Built-up roofing (BUR): Built-up roofing (BUR) is a flat or low-slope roofing system composed of multiple alternating layers of bitumen and reinforcing fabrics, finished with a protective surfacing such as gravel or mineral cap sheets.
Standing Seam System: Standing Seam System is a type of metal roofing assembly featuring continuous panels joined by raised, interlocking seams that run vertically from the roof’s ridge to the eaves, creating a watertight barrier.