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As a homeowner, there are roofing terms that you need to be conversant with to avoid the difficulties that you might have when communicating with your roofing contractors. Knowing these terms will also come in handy when you buying any roofing service for your home. Understanding the meaning of the roofing terms is particularly critical when you want to get an estimate for some roofing work.
In this post, we will list the roofing terms that you are most likely to encounter as a homeowner.
Roofing Glossary: Roofing Terms & Definitions You Need To Know
- Absorption – when it comes to roofing, absorption is how roofing material soaks up gases and liquids, like moisture
- Algae – these are a rooftop fungus that could leave dark stains on your roofing. In case you missed it, we have a great article about how to clean algae from your roof.
- Asphalt – this is a sticky, black substance, which is either a highly viscous liquid or a semi-solid form of petroleum. You can find it as a refined product or in natural deposits. Usually, it is classed as a pitch.
- ARMA – Asphalt Roofing Manufacturers Association. This is an organization of asphalt roofing manufacturers.
- Aluminum – a non-rusting metal, which is sometimes used for flashing and metal roofing. The most common is drip edge flashing which keeps the roofing eaves from being exposed to the weather.
- Aging – this is the effect on the roofing materials of being exposed to the environment over an extended period. Check out our article here on how long a roof will last due to aging.
- Air barrier – this is the assembly of materials that are used in building construction to minimize or slow down the passage of air into and out of your building.
- Alligatoring – undoubtedly, this is a new term to most new homeowners. But it should not scare you. It just describes the event when the surface bitumen cracks on a roof to create a pattern of cracks that resemble an alligator’s hide. The cracks produced could go through the bitumen, although they don’t in most cases.
- Aggregate – rock, crushed slag, crushed stone, stone, marble chips, or water-worn gravel used for ballasting and or surfacing a roofing system.
- Angled fasteners – these are roofing staples or nails that are driven into rood decks at an angle. They are not perpendicular to the deck’s surface and most commonly used on a sloping roof.
- Roof deck – the deck is a crucial structural component of the roof of a building. It should be capable of supporting the design of live and dead loads. Roof decks can either be combustible or non-combustible. The most common roof deck type for roofing is OSB (oriented strand board) due to it’s low cost. Read more about roof decks here.
- Live loads – these are temporary loads that a roof structure has to be able to support. They are defined as per the governing building codes. They can be environmental, moving, or dynamic and include such things as equipment, snow, wind, and people.
- Apron flashing – metal flashing used at chimneys of dormer fronts. Normally, you want to use the same material as the drip edge so there is no chance of corrosion. You can read more about roof flashing here.
- Cornice – the portion of the roof that projects out from the sidewalls of a house.
- Built-up roof – this is a low-slope roof that is covered by alternating layers of roofing felt and hot-mapped asphalt, and then topped off with a layer of gravel.
- Drip Edge– this is the string of metal that extends out beyond the eases or rakes to prevent rainwater from rolling around the shingles back onto the wooden portion of a house. To read more, check our our article on drip edge.
- Eaves – this is the lower edge of a roof – normally overhanging beyond the edge of a house. This area normally has flashing installed under the shingles to protect the fascia board.
- Rake – The rake is usually the slanting edge that is located at the end wall of your house.
- Ridge – this is the highest point on a roof. You can identify it as a horizontal line at the top edge of two roof planes that are sloping. This article is about ridge vents but it contains some pictures to identify the ridge.
- Ridge cap – this is a covering that is placed over your roof’s ridge. It is where two sloping parts of the roof meet and is covered by a special shingle made for the ridge.
- Shingle – this is a roof covering that comprises individual elements/units that are overlapping. These units feature rectangular shapes that are laid in courses starting from the bottom edge of your roof. Every successive course overlaps the joints below because they are flat. Shingles are usually made from different materials, including metal, wood, and asphalt.
- Counterflashing – the flashing that is embedded at its top in a wall or some vertical structure and it’s lapped down over shingle flashing.
- Flashing – these are components that are made of aluminum, galvanized steel, or aluminum. They can be rigid or flexible, and they are used to prevent rainwater from flowing close to roof openings. Basically, they seal your roof, and you can find them at perimeters, walls, valley, expansion joints, and drains, among other places.
- Flashing collar – this is an accessory of flashing that’s used to cover vents or other penetrations through your roof.
- Courses – Horizontal rows of tiles or shingles.
- Fascia – This is the trim board behind the gutter and eaves.
- Gutter – a gutter is a plastic or metal channel fixed to the lower edge of the roof of a building, which rainwater drains into.
- Rafter – a slanted, structural member to which sheathing is nailed.
- Sheathing – this is the rigid material (usually, 1-inch by 6-inch or 1-inch by 12-inch sheets or board of plywood) that is nailed to the rafters and to which shingles or other outside roofing materials are secured.
- Slope/pitch – this is the number of inches of vertical rise in a roof for every 12-inches of horizontal distance.
- Dormer – this is the small structure projecting from a sloped roof, normally has a window.
- Drip edge – the L-shaped strip that is installed along roof edges to let the water runoff to drip clear of the eaves, deck, and siding.
- Snow guard – these are the series of devices that are laid on the roof. They are set in a specific pattern that allows them to hold the snow into place. They are meant to prevent sudden ice or snow slides from a roof.
- Soffit – the soffit is an interior or exterior feature that is situated under the fascia board. In fact, it is the board that you see the largest part of when you’re at street level.
- Felt or underlayment – this is a sheet of asphalt-saturated material that serves as a second layer of protection for the roof deck. 30# and synthetic are the most popular types of felt.
- Exposure – this is the part of a shingle that is exposed to the weather. It is normally less than half its length.
- Valley – this is the angle that is formed where two sloping roof surfaces intersect. The feature is usually protected by metal valley flashing because it collects the water run-off from two roofing planes.
- Square – this is 100 square feet of roof or rather, the amount of roofing material that is required to cover 100 square feet when it’s properly applied. There are three bundles in a square of asphalt shingles.
- Skylight – this is a roof accessory designed to look like an opening in your roof. Its purpose? To admit light into the house or attic. The skylight is usually transparent to make sure enough light gets into a house.
- Blind-nailing or back-nailing – this is the act of nailing the back part of a steep roofing unit or roofing ply to make sure that the fasteners are well-covered by the next overlying ply or course. This action also makes sure that the fasteners are protected from harsh weather elements on your roofing system.
- Base ply – this is the lower-most ply in your roofing system and or membrane.
- Base sheet – this is the saturated, impregnated, or coated felt that the roofing experts place as the first ply where there are multiple plies. It is also the first sheet on modified bitumen roofs.
- British Thermal Unit (BTU) – this is the amount of heat that is needed to increase the temperature of 1lb of water by 1 degree F.
- Button punch – this is the act where roofing professionals will indent two or more thicknesses of your roof’s metal. This process is undertaken to avoid slippage between the metals.
- Fire rating – this is a system for classifying the fire resistance of different materials. Normally, roofing materials are rated Class A, B, or C. Class A roofing materials are the ones that have the highest resistance to fire emanating from outside the building.
- Louvers – these are devices that have slatted apertures, which are normally installed in a soffit or gable to allow ventilation of the space below the deck. They also help to equalize the moisture and air temperature.
- Penetrations – this is anything that penetrates the roof deck, including stacks, pipes, vents, and chimneys.
- Truss – now, these are the engineered components whose purpose is to supplement rafters in many newer homes and commercial buildings. Trusses are usually built for a particular application, which means that they cannot be cut or altered.
- Vapor retarder – this is a material or system that’s designed to efficiently retard the transmission of water vapor under certain conditions. It acts as a barrier.
- Canopy – this is a projecting or overhanging roof structure. It is constructed over an entrance or a door. The end of some canopies is left unsupported but is still stable.
- Cap sheet – basically, this is a coated sheet that’s placed at the top of some modified (could also be built-up) bitumen membranes or flashing.
- Chalk – this is a residue, normally appearing powdery, which you see on the surface of your roof’s material.
- Chalking – this is usually the degradation of an ingredient, coating, paints, or other materials.
- Asphalt primer – this is an asphalt-based primer that’s used to prepare the surface of metal, concrete, or other materials in order to make sure that they have adhered. It meets ASTM D41.
- ASTM – ASTM international. It is an organization that usually develops and publishes voluntary consensus standards, specifications, and test methods for a wide range of materials, including roofing.
- Cladding – this is the material that’s used as the enclosure of your building. Particularly, at your exterior wall.
- Coating – this is a layer of material that a roofing professional will apply on a surface for either decoration or protection, including on roofs. Coatings for SPF are usually semi-liquids, liquids, spray, mastics, roller, or brush applied.
- Concealed-nail method – this is the process where all nails on an asphalt roof are driven into the underlying course and then covered by an overlapping course that must be adhered.
- Cut-off – this is a feature that is designed to distinguish the sections of a roofing system. It usually has a permanent detail.
- Attic – The attic is the space under your roof. You will notice that it is ventilated to make sure there’s proper air circulation in it when there’s excessive heat.
- Dead level – this is a horizontal rooftop or deck that does not have a slope leading to the drains on your roof. It’s essentially flat.
- Deflection – this term in roofing has quite a different meaning from the norm. It is the downward displacement of a roofing structure when it is under a load.
- Dome – like the name suggests, this is a roof that looks like a half-circle facing downwards.
- Drain – this is an outlet on the roof area that’s designed to make sure runoff water gets off your roof seamlessly.
- Caulk – the process of using asphalt or mastic cement to fill a joint so as to prevent leaks.
- Bundle – this is a package of shingles. Normally, you’ll find 3, 4, or 5 bundles in each square.
- Collar or vent sleeve – this is a preformed flange that is placed over a vent pipe to seal the roof around the vent pipe opening.
- Oriented Strand Board (OSB) – These are roof deck panels that are made of narrow bits of wood. They are usually installed as a substitute for plywood sheets.
- Plywood – these are roof deck sheets that are strong, durable, and have a lightweight design. Plywood has several grades, ranging from A to D. Only exterior grade plywood is used for decking a sloped roof.
- Granules – this is a ceramic-coated, color-crushed rock that is applied to the exposed surface of asphalt roofing products.
- Hip Roof – This type of roof has an inclined external angle that runs from the ridge to the eaves. You will find it where two sloping planes meet.
- Overhang – this is the portion of the roof structure that extends beyond the exterior walls of a building.
- Open valley – this is a method of construction where the shingles on every side of the valley are trimmed to ensure that the valley flashing is exposed. Moreover, it makes sure that the shingles don’t go beyond the valley.
- Expansion joint – this is the joint that separates two building elements. It promotes free movement while also preventing damage to your roofing system.
- Fasteners – these are a wide range of mechanical devices that are used for assembling and securing roofing material. They include bolts, cleats, nails, clips, and screws. Click here to read more about roofing nails.
- Ferrule – this is a small metal sleeve that is put in your gutters. Particularly, at the top. Usually, it helps to hold your gutter in place, plus, it also makes sure that they keep their original shape; hence, also acting as a spacer.
- Slate – generally, slate is a type of roofing that is exceptionally durable. The best part, this roofing material is resistant to fire and does not support the growth of mold or fungus. Besides, it is waterproof and can last for more than 100 years. These features make it ideal for areas with a wet climate. It is slowly being phased out by synthetic slate.
- Saddle – you might have seen a structure on the higher side of chimneys. Well, that’s the saddle, and it helps to divert water around it when it rains.
- Roll Roofing – This is a cheap (often short term) solution to repair your roof. We have a whole article dedicated to roll roofing if you want to read more.
- Gable Roof – Check out this YouTube video below for a video explanation on Gable Roofs.
- TPO Roofing – Thermoplastic Polyolefin roofing, better known as TPO roofing, is a popular and common design to many industrial and commercial roofing today. It’s a single-ply roofing system that’s gained popularity because of its bright design and durability.
- Wood Shingles – Historic properties are well known for having wood shake or wood shingle roofs. They are beautiful (although expensive) and can last a really long time if installed correctly.
- Ice & Water Shield – This is a protective membrane that is installed on your entire roof perimeter as well as the valleys. It is probably one of the best roofing materials invented in the last 100 years.
- Starter Shingles – Starter shingles is a roofing term most of you know. It is the first shingle that is laid down. It is typically a little thicker and stronger as this gets the most punishment from wind.
- Roof Warranty – As the name suggests, this roofing term is about the insurance policy you have on your roof with the roofing manufacture and the roofing installation company.
- Frieze Board – It is a kind of trim that is usually installed between the soffit and the top of a house’s siding.
What other roofing terms did we leave out? There are so many roofing terms it is hard to remember all the parts of a rooftop so we would love if you would comment in the section below and let us know what roofing vocabulary we left out. If you are reading and learning about how to roof your house, we suggest just speaking to a professional to save you from needing to learn all these roofing terms.
