Roofing Terms


Homeowners who understand the basics of how a roof is constructed are in a better position to discuss their roof with contractors and roofers. The roofing terms explained in general below are standard throughout the construction industry. Aurora roofing professionals can explain more about the specifics if necessary.

Roofs are constructed in a variety of types. Some of the most common types include gable, hip and gambrel. Houses with flat roofs have different needs than other types since water does not roll directly off of them.

Roofs are usually held up by wooden supports known as rafters. Some type of sheathing is attached to the rafters. The most common type of sheathing is made of plywood boards. Underlayment is used to cover the sheathing, and finally shingles or shakes or other materials are attached on the top of the roof.

The sheathing creates a flat surface known as the roof deck. The deck creates a surface for roofers to stand on as they work. The shingles, shakes or other materials are known as the roof surface. The roof surface is the front line of protection against the elements. If water is penetrating the roof surface, ultimately it will cause problems.

If the roof isn’t flat, then shingles and shakes are attached in straight lines called courses. They overlap each other slightly, and the areas that overlap are used to cover up nail heads from moisture.

The area of a course of shingles or shakes not covered by the course on top is known as the exposure since it is open to the elements. The part of a course that covers the shingles below is known as the butt.

Asphalt shingles are the most common material used to cover a roof surface. A course of asphalt shingles does not run the entire horizontal length of a roof unbroken. Rather, it is attached into sections known as tabs.

A roof’s pitch is a set of numbers that describe how steep the roof. The ratio is expressed as rise to run in inches. For example, a roof with a four in 12 pitch rises four inches for every foot horizontally.

Roofs are usually penetrated by objects from below such as pipes, chimneys and skylights. Wherever this occurs, there is an increased risk of water getting into the roof. Therefore, flashing, the flat material usually made of metal or plastic, is attached over exposed areas to add additional protection.

Gutters are attached to the edges of roofs. Their purpose is to carry water to downspouts and then away from the house. The water can’t simply be dumped by the downspouts or else it will leak into the foundation.

Terms a roofer may use:


This term is used to describe something as it relates to the immediate surroundings. When used in roofing, this term can refer to any variety of immediate factors in the air that can affect the roofing system, such as the temperature or the sound.

Angled Fasteners

Nails and staples that are used on the deck of a roof at an angle. This type of product is used on areas that are not parallel to the deck and help to secure the roofing materials.


This occurs when roofing materials begin to get bubbles or pimples. It is usually caused because of moisture. If asphalt shingles begin to blister, this may happen because moisture is either trapped under the material or inside the material.

Class A rating

This is the highest rating on a three step scale of roof material fire ratings. Class A rating implies the highest degree of resistance in case of a fire and is also categorized by a minimum spread of flame. In terms of fire safety, Class A is the best quality product that can be used.

Class A fire rating

This is the highest rating given to construction materials. It is designed to identify the relative combustibility of materials. A material that is rated as class A has a lower flame spread rate than a more combustible material that might be rated class C.

Clay Tiles

Clay roofing tiles are often made using natural pigments or colors; however, there are many styles available and some manufacturers are even offering a wider range of color choices. These tiles are available in several profiles, adding even more style choices for homeowners.

Design loads

This term refers to the amount in a load that a building can withstand as specified by the relevant federal, state or county bodies of government. If this load is exceeded, there may be resulting structural damage to the building.


The edges of any roofing system that extend beyond the walls of a building are referred to as eaves. Eaves serve a practical purpose, as this overhang ensures that water is thrown clear of the walls and foundation. Eaves are often decorated and are typically equipped with a gutter system to assist in directing water away from the roof.

Expansion joints

An expansion joint is a gap or joint that allows the roof to expand or contract with quick temperature changes. These joints safely absorb movement or vibrations as well as minimize the chances of structural damage occurring to the home.


Fascia is a band under a roof edge or a vertical frieze. Since it’s not exposed to weather like the rest of the roofing system, damage to the fascia usually indicates problems with the gutters.


This is a reinforced glass fiber. The glass fibers may be arranged together in a random pattern, or else flattened into a sheet, laid out in a holding pattern or woven into a fabric. Depending on what it is used for, various types of glass can be used to make fiberglass.


This construction term refers to the main supervisor at a job site. Also known as the on site supervisor, the foreman is the main manager who everyone reports to during a workday. Any project discrepancies are solved with a foreman’s perspective.

Galvanized steel

This is steel that has been put through a process designed to prevent it from corroding. The steel has a zinc oxide coating that makes it difficult to rust, harder to scratch and gives it a nice finish that most people find attractive.

Glass felt

This roofing material is a mixture of bitumen, resin and glass shards to form underlayment and other products. Glass remains a strong yet flexible material to add along rooftops. It can flex and return to its original shape during any season.

Gutter joints

Although they look like one long piece, gutters are often a collection of several pieces held together by clips. A gutter joint is the area where two pieces are clipped and covered with a sealant.


A roof or rain gutter is a narrow channel, or trough that is one of the important components of a roofing system. The gutters, also known as rain catchers, collect rainwater and divert it away from the edge of the roof.

High reflectivity films

High reflectivity films attach to a window or skylight by way of static electricity. They help to stop the flow of sunlight into the house, minimizing passive solar heat gain and fading due to ultraviolet radiation.


This roofing designation refers to a connection point where two sides meet on a structure. Most homes have more than one hip, giving the building architectural depth and structural support. Hips flank the home on the left and right sides in many cases.

Home performance evaluation

A home performance evaluation is a service provided by local roofing and home building experts. This evaluation includes a home inspection and a written report about inefficiencies that are in need of improvement.

Implied warranty

An implied warranty is understood, often backed by local, state or federal law and provided to the consumer automatically without the need to be expressly defined in a legal document. An express warranty usually cannot supersede an implied warranty.

Insulation baffles

Insulation baffles prevent loose fill insulation from blocking vents in attics that permit cooler outside air to enter attics through the eaves and warmer air to exit through ridge or roof vents. Plastic, extruded foam and even cardboard represent typical materials used to build these baffles.

Load bearing walls

Load bearing walls are the ones that actually provide support for a home and roof, and they are what keeps a home standing. These structural walls transfer the weight placed upon them to the foundation.

Net metering

The term net metering describes how customers with excess solar energy generating systems receive compensation for the electrical energy returned to the power grid. Full retail net metering means that customers receive the same rate per kilowatt that they pay for electricity from the utility company.


“Pitch” is another word for a roof’s angle or slope. The pitch of a roof can be expressed as a slope ratio, such as 3 units of rise for every 12 units of length. Pitches and slopes can also be expressed in degree units, which are used to describe angles.

Polymeric sealant

Polymer sealants are made to coat a variety of metal panels, including roofs. They’re generally UV resistant, function in both extreme heat and cold and can be painted with a water based paint.

PV panels

PV panels consist of an array of photovoltaic elements that retrieves solar energy from the sun, and transforms that energy into electricity. A photovoltaic system includes a panel, solar modules, an inverter, a battery or solar tracker, and interconnection wiring.

R value

It is a measure of thermal resistance of a material. The R value depends on the thickness of the material, as well as the material itself. A product with a higher R value will prove to be more effective as an insulator. Installation of insulation material in multiple layers compounds the R value.


The rafters are the pieces of wood that form the “skeleton” of the roof. On top of this structure lies the sheathing or decking, which forms the large flat area for the shingles. Since the rafters hold up the roof, it’s essential that they are in good condition.


This term refers to the internal beams and support system upon which the foundation of the roof rests. Rafters are susceptible to weakening due to moisture, mold and rot. Protection and upkeep of rafters and supporting joists is one of the most important aspects of roofing maintenance.

Replacement value

Actual value is the estimated value of a roof factoring in depreciation. Replacement value is the estimated cost of replacing a roof regardless of the value of the existing roof. RV is usually greater than AV.

Roof Deck

Most homes have a roofing system that has multiple components. The roof deck is the part of the roof that provides the flat surface or base. It is installed over the support structure. Shingles or other roofing materials will be attached to the deck.

Roofing membrane

A roofing membrane is installed underneath roofing materials to help prevent water from rain or melted snow from soaking into an attic. However, a roofing membrane will not stop ice dams from forming. It will simply limit the damage caused by ice dams.


This term refers to any variety of compounds that can be applied to a primary material to improve its qualities. Usually, sealants are applied to porous surfaces to help them resist moisture and rot damage.


Wood shakes are split from a log usually by hand giving them a rougher texture than wood shingles which are sawn from blocks of hardwood. Shakes can be split on one or both sides and are valued for their natural appearance rustic feel.

Shingle square

A shingle square is a measurement of convenience, and it makes purchasing shingles easier because every square is specific to the particular shingle. A square provides enough material to cover 100 square feet of roof.


Is a smooth sedimentary rock derived from shale formations. It is valued for its fine grain and coloration. Slate ranges in color from grey to black sometimes with a blue tint. The high pressure that forms ash and clay into slate gives it its striated layers.

Slate hammer

This is a type of hammer that has been especially designed to be used to work with slate roofing. It is able to punch holes in slate shingles as well as cut, trim and shape the slate being used on a roof.

Spike and ferrule

This gutter term is an old fashioned fastener that connects directly through channels and into fascia. A spike pierces the channel’s upper edge while attaching to fascia with ferrule support. Many homes still have this reliable fastener at the roof’s edge.

Slope correction

An inherent assumption in a load limit calculation is that pressure is equal across the roof, but this is often not the case on a steep roof. A slope correction lowers the psf limit to account for this difference.

Snow guards

These rooftop components are physical barriers added to homes in areas prone to snow. As snow falls, it’s held back by guards. Anyone walking below roof eaves is safe from any unexpected snow volumes falling from the roof.


In architectural terms, the word soffit describes the underside of a construction element. For example, the underside of an arch, the underside of a flight of stairs, the underside of the chimney, the underside of kitchen cabinets or the underside of a roof can be referred to as the soffit.

Solar reflectance

This is the amount of incident solar energy that gets reflected from a surface. Some manufacturers will measure the visible reflectance of a roofing material. This is measured by looking at the part of the solar spectrum that has wavelengths between 400 and 700 nanometers.

Spanish Tile

Spanish tile has been a traditional roofing material throughout the world for many centuries. These clay tiles are made with natural materials and offer a long lasting and very durable roofing option. They are generally formed into an S shape, which gives them a very distinctive look.

Stone coated steel

Stone coated steel roof panels are pre formed metal roof panels designed to look like asphalt shingles, cement tiles, cedar shakes or slate tiles. For extra durability, noise protection and visual appeal, the metal is coated in crushed stone particles.


Paper like material which is attached between the roof deck and surface. Underlayment is generally self adhesive. It is waterproof so that water does not get into the attic but is also porous so that moisture can escape the roof.

Vapor retarder

This roofing term describes a thin film that’s installed on a surface to prevent moisture accumulation. Roof decks and metal panels can easily trap moisture between their layers. Vapor retarders simply impede water from remaining in the space and reducing damage.

Wood Shakes

Wood shingles that are installed on roofs to protect the interior of a building from the weather and environmental elements. They are often constructed out of cedar trees and have a long lifespan if they are maintained well.