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Must-Know Roofing Terms Every Homeowner Needs to Know Before Hiring a Contractor!

Roofing Terminology

Before you can accurately understand a roof assessment or a roofing estimate, you should be familiar with roofing terminology. Below are some commonly used terms that identify parts of a roof and types of roofing.



Rooftop fungus that can leave dark stains on roofing.

Angled Fasteners:

Roofing nails driven into decks at angles not parallel to the deck.

Apron Flashing:

Metal flashing used at chimney fronts.


A bituminous waterproofing agent used in various types of roofing materials.

Asphalt Plastic Cement (Tar):

Asphalt based sealant material, meeting ASTM D4586 Type I or II. Used to seal and adhere roofing materials. Also called mastic, blackjack, roof tar, bull.



Bubbles or pimples in roofing materials. Usually moisture related. In shingles blisters are caused by either moisture under the material or moisture trapped inside the material.


When shingles are subjected to high winds and are forced off a roof deck.


When a wrinkle or ripple affect shingles or their underlayment’s perception.


Counter Flashing:

The metal or siding material that is installed over roof-top base flashing systems.


A peaked water diverter installed behind chimneys and other large roof projections. Effectively diverts water around projections.


When shingles are improperly installed over an existing roof or are over-exposed, they may form a curl or cup. May also be due to a manufacturing defect.



A raised roof extending out of a larger roof plane.

Drip Edge:

An installed lip that keeps shingles up off the deck at edges and extends shingles out over eaves and gutters.

Down Spout:

A pipe for carrying rainwater from a rain gutter.



The roof edge from the fascia to the structure’s outside wall. In general terms, the first three feet across a roof is termed the eave.

End Laps:

When installing rolled products in roofing, the area where a roll ends on a roof, and is overlapped by the next section of rolled material.


The area on any roofing material that is left exposed to the elements.



Nails or Screws used to secure roofing to the decks.

Fiberglass Mat:

Fibers condensed into strong, resilient mats for use in roofing materials.


Metal pan extending up or down a roof slope around flashing pieces. Usually at chimneys and plumbing vents.


Materials used to waterproof a roof around any projections.


Gable Roof:

Traditional roof style; two peaked roof planes meeting at a ridge line of equal size.


Crushed rock that is coated with a ceramic coating and fired, used as top surface on shingles.



The method to assure sealing of shingles on very steep slopes, in high wind areas, and when installing in cold weather.

Head Wall:

Continuous metal flashing consisting of several feet of metal. Used at horizontal walls, bent to resemble an “L”.

High Nailing:

When shingles are nailed or fastened above the manufacturer’s specified nail location.

Hip Legs:

The down-slope ridges on hip roofs.

Hip Roof:

A roof with four roof planes coming together at a peak and four separate hip legs.


Laminated Shingles:

Shingles made from two separate pieces that are laminated together. Also called dimensional shingles and architectural shingles.

Low Slopes:

Roof pitches less than 4:12 are considered low sloped roofs. Special installation practices must be used on roofs sloped 2:12-4:12. Shingles cannot be installed at slopes less than 2/12.


Mansard Roof:

A roof design with a nearly vertical roof plane that ties into a roof plane of less slope at its peak.


The general term for the base material of shingles and certain rolled products.


Mixture of sand, mortar, limestone and water used in bonding a chimney’s bricks together.


Nail Guide Line:

Painted line on laminated shingles, to aid in the proper placement of fasteners.


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


Open Valley:

Valley installation using metal down the valley center.


Oriented Strand Board. A decking made from wood chips and lamination glues.


The term used for fasteners driven through roofing material with too much force, breaking the material.


Installing shingle courses higher than their intended exposure.


Parapet Wall:

A barrier which is an extension of the wall at the edge of a roof.


Rake Edge:

The vertical edge of gable style roof planes.

Rigid Vent:

Hard plastic ridge vent material.

Roof Louvers:

Rooftop rectangular shaped roof vents. Also called box vents, mushroom vents, airhawks, soldier vents.



Sealant installed on shingles. After installation, heat and sun will activate sealant to seal the shingles to each other.

Shed Roof:

Roof design of a single roof plane. Area does not tie into any other roofs.

Side Walls:

Where a vertical roof plane meets a vertical wall. The sides of dormers etc.

Soffit Ventilation:

Intake ventilation installed under the eaves, or at the roof edge.

Starter Strip:

The first course of roofing installed. Usually trimmed from main roof material.

Step flashing:

Metal flashing pieces installed at sidewalls and chimneys for weatherproofing.



Removal of existing roofing materials down to the roof deck.


When shingles reflect the uneven surface beneath them.

Ex: Shingles installed over buckled shingles may show some buckles.


When a roof plane ties into another roof plane that has a different pitch or slope.



Term used to describe a fastener not fully driven flush to the shingles surface.


Asphalt-based rolled materials designed to be installed under main roofing material to serve as added protection.



Area where two adjoining sloped roof planes intersect on a roof creating a “V” shaped depression.


Waterproof Underlayment:

Modified bitumen-based roofing underlayment. Designed to seal to wood decks and waterproof critical leak areas.

Woven Valleys:

The method of installing valleys by laying one shingle over the other up the valley center.

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