Welcome to Four Seasons Metal Roofing’s comprehensive glossary of metal roofing terms. Whether you’re a homeowner considering a transition to metal roofing, an architect looking to specify the right materials, or simply someone keen to expand their knowledge, this glossary is designed to be your go-to reference.

We recognize the vast array of terms and jargon in the roofing industry can sometimes be daunting. With this glossary, our aim is to simplify and clarify, providing concise explanations for industry-specific terms. Dive in to better understand the nuances of metal roofing, and remember, a well-informed decision is always the best decision.


Loose mineral granules or crushed stones embedded in the surface of some roof materials to add color, reflect sunlight, and increase durability.

Aluminized Steel

A steel coated on both sides with an aluminum-silicon alloy, providing corrosion resistance and heat reflectivity.


A mixture of two or more metals combined to achieve improved properties like strength or corrosion resistance. Common roofing alloys often include zinc, copper, and aluminum.

Ambient Temperature

The temperature of the surrounding environment. In roofing, it’s essential to know when applying certain materials that have temperature-sensitive application ranges.

Anodic Coating

A protective layer formed by the application of an electrolytic process that thickens the natural oxide layer of metal surfaces.


A material, often stones or pavers, used to hold roofing materials in place. It’s commonly used with single-ply membranes.

Bare Metal

Metal that does not have a protective coating, making it susceptible to rust and corrosion.


Wooden or metal strips laid vertically on the roof deck on which the roofing panels are attached.


Bubbles that may appear on the surface of asphalt roofing after installation.

Box Gutter

A rectangular rain gutter, typically set between parallel surfaces in a roof, as between the vertical wall of a dormer and its roof.

Cant Strip

A beveled or triangular-shaped strip of wood, wood fiber, or other material used to taper the layers of roofing in the area of transition.


A device that holds two panels together, allowing for the metal’s natural expansion and contraction with temperature changes.

Clip-locked Roofing

A design in metal roofing where panels are mechanically attached to the structure by using clips.


A layer applied on metal roofing materials to protect from elements and provide color. Common coatings include PVDF and SMP.

Cool Roof

Roofing materials that reflect more sunlight and absorb less heat than standard roofing products, reducing cooling costs in warm climates.


The ridges and grooves on a metal panel which give it added strength and allow for water runoff.


The piece of metal used to prevent water from penetrating the joint where a roof meets a wall.


A method of joining panels together by folding or bending one edge over another edge, securing the two panels together.


A term used to describe a flat roof or a roof with no slope.


A structure projecting from a sloping roof, usually with a window. It has its own roof, which may be flat, arched, or pointed.

Drip Edge

A metal flashing or other overhanging component with an outward projecting lower edge, intended to control the direction of dripping water and help protect underlying building components.

Expansion Joint

A joint allowing for the expansion or contraction of roofing materials due to temperature changes.


The lower edge of the roof that overhangs the building’s side.

Eave Flashing

Metal sheets or strips applied to the overhanging edges of the roof to prevent water from seeping under the roofing material.


Another term for gutter, which collects rainwater from the roof and channels it away from the building’s foundation.


The ability of a roofing material to stretch or elongate without breaking.


The portion of the roofing exposed to the elements, especially regarding shingles or tiles.


A flat board, band, or face located at a cornice’s outer edge. In roofing, it’s often where gutters are attached.


The screws or nails used to secure roofing materials to the structure. For metal roofing, these often come with specialized washers to prevent leaks.

Fastener Flange Roofing

A metal roofing system where the roofing is secured using fasteners at the overlap flange.

Felt Course

A continuous roll of felt laid out on the roof, often before the final roofing material is applied.


A decorative piece at the apex of a roof; typically pointy and ornamental.


Pieces of metal used to prevent water seepage into a building around any intersection or projection, such as vent pipes, chimneys, valleys, and joints at vertical walls.

Flash Point

The temperature at which a particular substance ignites. In roofing, it refers to the safety of the materials in case of fire.


Refers to the thickness of the metal. In roofing, lower gauge numbers mean thicker metal.


The triangular portion of the endwall of a building directly under the sloping roof and above the main eave line.

Gable End

The triangular portion of the wall beneath the end of a gabled roof.

Gable Vent

A vent placed in the gable end of a house, near the peak of the roof, allowing hot, moist attic air to escape.

Galvanic Corrosion

A type of corrosion that occurs when two different metals are in contact in the presence of an electrolyte, like water.


A trademarked steel sheet product coated with an alloy of about 55% aluminum, 43.5% zinc, and 1.5% silicon. Offers improved corrosion resistance compared to traditional galvanized steel.

Gutter Apron

A type of flashing that directs water into the gutter system from the roof.


The distance of overlap where one roofing material covers another.


The fold created when the edge of a metal panel is bent back on itself, usually to add rigidity or join pieces.


The process of folding back the edge of a metal panel to give it added rigidity and ensure a clean edge.


The external angle or fold where two sloping roof sides meet.

Hip Roof

A roof that has four sloping sides. It’s more stable than a gable roof and provides more space, but it’s also more expensive.

Hydrostatic Pressure

The pressure exerted by a fluid due to its weight, crucial in understanding certain aspects of flat or low-sloped roofs.

Ice Dams

A ridge of ice that forms at the edge of a roof, preventing the melting snow from draining off. This can cause water to leak into the home if precautions aren’t taken.


The angle or slope of a roof, often referred to as the pitch.

Infrared Thermography

A technology used to detect water or moisture trapped in roofing systems by identifying temperature variations.


Metal or wood brackets used to support toe-boards on steep-slope roofs.


A metal trim shaped like the letter “J” used around windows, doors, and at the roofline to finish off the siding’s raw edges.

Joist Hanger

A metal piece that supports the horizontal joist, which in turn supports either the building itself or decking on a flat roof.

Kick-out Flashing

A piece of flashing that diverts water away from a wall and into a gutter.

Knee Cap

The cover trim that joins a wall to a sloping roof, typically at the point where an upper roof slope meets a lower section.

K-Style Gutter

A type of gutter system shaped like the letter “K”, known for its decorative appearance and high water-carrying capacity.

Kynar Coating

A type of highly durable, premium paint finish that resists fading, chalking, and corrosion, commonly used in metal roofing.

Live Load

The weight added to the roof by snow, rain, workers, equipment, and other temporary conditions.


A slatted device installed in a gable or soffit (the underside of eaves) to ventilate the space below a roof deck and equalize air temperature and moisture.

Low-E Coating

Stands for “low emissivity.” A thin coating applied to roofing materials to reduce heat transfer and reflect more light than dark colors.

Mansard Roof

A type of roof with two slopes, with the lower slope being steeper than the upper, almost flat slope.


A thick adhesive material used to seal roofing components.


A thin layer or sheeting used under the metal roofing to prevent water infiltration.


The joint made by beveling the adjacent edges of two pieces of roofing material to fit together.


A vertical bar or divider in the frame between windows, doors, or other openings.


A piece of lumber secured to non-nailable decks and walls by bolts or screws, and it provides a suitable backing onto which roofing materials can be nailed.


When a nail is not fully driven, it sits up off the roof deck.

Neoprene Washer

A type of washer made from a synthetic rubber compound, often used with roofing screws to ensure a watertight seal.

No-cutout Shingles

Shingles that are solid and don’t have cutouts or slots.

Non-woven Fabric

A type of fabric used in certain roofing applications, often for reinforcement.


A process that removes part of a metal panel, allowing it to fit around obstacles or for design purposes.


A double curve, resembling the letter ‘S’, used in moldings.

Open Valley

A method of valley treatment in which the two sides of the valley overlap, but leave the valley center exposed, usually lined with metal or rolled roofing.

Organic Felt

A type of felt paper that is made from wood pulp and used in built-up roofing and as an underlayment for asphalt shingles.


The mistake of applying too much force when installing screws or nails, potentially damaging the roofing material.


Where two pieces of roofing material cover each other to prevent leakage.


The portion of the roof structure that extends beyond the exterior walls of a building.

Panel Profile

The design and dimension characteristics of a metal roofing panel type.


A wall-like barrier at the edge of a roof, terrace, balcony, or other structure.

Parapet Wall

The part of any wall entirely above the roof line.


The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet.


A process where metal is cooled rapidly, often used in the making of metal roofing materials to achieve certain properties.

Quick-setting Cement

An asphalt-based cement used to adhere tabs of strip shingles to the course below.


Decorative rectangular blocks that are used to highlight the corners of a building, often seen on more traditional architectural styles.


The inclined edge of a sloped roof over a wall from the eave to the ridge.


The supporting framing to which a roof deck is attached.

Ribbed Panel

A metal roofing panel design that has raised sections, increasing its structural strength.


The top edge of two intersecting sloping roof surfaces.

Ridge Cap

A material or covering applied over the ridge of a roof.

Roof Assembly

A term referring to the various layers that make up the roof.


A structure located behind the higher side of a chimney (or similar projections from the roof) to divert rainwater around it.


The joint or overlap between roofing panels.


The process of joining two adjacent metal panels together using a specialized machine. This ensures a tight and waterproof seal.


The underside of a building element or structure, like a roof overhang or archway.

Standing Seam

A prominent vertical seam in which adjoining steel panels are joined.


The layer beneath the metal roofing, often sheathing or existing roofing material.

Termination Bar

A bar, usually metal, used to secure and seal the top edge of a base flashing membrane.

Terne Coating

An alloy coating of lead and tin used on some steel and copper roofing.

Terne Metal

A soft metal alloy, mainly lead and tin, used in some historic metal roofing applications.

Thermal Bridging

Occurs when a more conductive material allows an easy pathway for heat transfer across a thermal barrier.

TPO (Thermoplastic Olefin)

A type of single-ply roofing membrane known for its heat-reflective properties.


An assembly of beams or other elements that creates a rigid structure.


A drain positioned to carry away underground water.


A barrier material laid over the substrate and below the metal roofing, providing additional insulation and protection against water and ice damming.


A roofing term for the upward force exerted on roofing materials by wind.


The angle formed by the intersection of two sloping roof surfaces, typically collecting a lot of water and requiring special treatment to prevent leaks.

Valley Metal

A V-shaped metal channel used in the valleys of a roof to guide water off the roof.

Vapor Retarder

Any material used to prevent the passage of water vapor.

Vent Stack

A pipe that allows air to circulate among roofing components and the outside, ensuring that pressure is equalized.


A lower interior wall surface (contrasting with the wall above) that is often made of paneling.


The capability of a roof or material to prevent the passage of water, even in adverse conditions.


The changes in color, texture, and material properties a metal roof undergoes when exposed to environmental conditions.

Weep Holes

Small holes in metal window sills or other architectural components that allow for water to drain, preventing water buildup and damage.

Wind Load

The force exerted by wind on structures.

W valley

A type of valley where the middle part forms a ‘W’ shape, designed to improve water runoff.


Cross-bracing using two diagonal members crossing each other.


The coverage rate of a particular roofing material or substance.

Yield Strength

The amount of stress a metal roofing material can withstand without undergoing permanent deformation.


The horizontal bar that holds the panes of a window together.

Z-bar Flashing

Bent, galvanized metal flashing that’s installed above windows, doors, and other openings to prevent water infiltration.


A process where steel is coated with a layer of zinc to protect it from rusting.


A patented coating made of aluminum, zinc, and silicon that offers protection for steel roofing and enhanced corrosion resistance.

Zoning Regulations

Laws established by local municipalities that affect various aspects of roofing, such as height, design, and materials.

We hope this glossary helps clarify some of the terms you may come across when considering or working with metal roofing solutions. If you have any questions or need further clarification on any roofing matter, the Four Seasons Metal Roofing team in Toronto is always ready to assist. We’re passionate about providing our community with quality roofing solutions that last a lifetime!

Our Customers Love Their Metal Roofs!

Check out some of our recent Google reviews from customers
Tony PhamTony Pham
19:01 31 Mar 24
The salesman George explain to us everything in details. The crew was amazing they did the job on time and with no hassle. Highly recommend!
Richard CattonRichard Catton
18:12 31 Jan 24
I needed a single piece of custom flashing bent up. I contacted Dave at Four Seasons Metal Roofing, 78 Mearns CRT. Bowmanville. Dave was so helpful. He made up the required flashing in about 10 minutes. Excellent customer service and great attention to detail. I will definitely bring all future business here.Thanks Dave
MR RaptorMR Raptor
13:43 13 Nov 23
Great experience with Dave picking up a metal snow stopper piece! Professional, friendly service!
czar Hagorilesczar Hagoriles
20:25 08 Nov 23
Simon and Dave were very helpful, kind and professional. I had my roof done last summer from this company and they did a very good job. Albert James the sales rep is also very friendly and true to his words. Their installer is very experienced and had good manners as well.
Jenn DoumaJenn Douma
17:23 06 Nov 23
Great product. Dave and Simon have been very helpful with getting us exactly what we were looking for.
kevin campbellkevin campbell
21:54 23 Oct 23
We couldn't be happier with our roof thank you Four seasons. We were greeted as friends what an amazing experience.
Jenn BondJenn Bond
17:44 13 Oct 23
Great experience! Dave was very helpful and informative. He was able to solve my problem and get me exactly what I needed at such a reasonable price! Thank you Dave! Would recommend!
Eric RowlandsEric Rowlands
18:28 31 Aug 23
Dave helped me out huge, took the time to explain my options and had everything finished up for me within an hour. Very professional, will come back.
Mie Tha LahMie Tha Lah
21:33 21 Aug 23
My family is very happy with the crew of Sir Milos with the metal roof installation of our home. They did outstanding job!!!!
carol johnstonecarol johnstone
15:43 07 Jun 23
Was very pleased with the workmanship , and installation . Our roof looks great , best looking house in the court . Would recommend. this company .
Shofiqul IslamShofiqul Islam
15:37 20 May 23
Excellent service. Necessary work completed within a short timeframe and with high quality. I would strongly recommend Four Season Metal Roofing for your future project.
Don DrysdaleDon Drysdale
22:10 09 May 23
Blown away! Confident sales manager and straight forward. True to his word, work was commenced sooner than expected and installation was completed in 1 day. Great hard working crew and very pleased with the clean up and final product. 5 stars plus!
Gbenga AdejuyigbeGbenga Adejuyigbe
02:03 01 May 23
The metal roof installation crew was professional, courteous and friendly. The metal roof is beautiful and very well installed. We are very pleased we selected Four Seasons Metal Roofing.
Angie PatelAngie Patel
18:42 29 Apr 23
Very courteous, quick response for any questions asked. Dave was the one we dealt with. Dave also gave us tour of the plant in Bowmanville. Everything was cleaned up end of each day. Workers came on time. Job was done in 2 days.
Deb HudsonDeb Hudson
10:47 08 Mar 23
Extremely pleased with my new roof. The materials arrived at 9am and the crew of roofers arrived at 10. The best thing was next to no garbage usually you see a dumpster full. Four Seasons Metal Roofing is definitely the way to go

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