Roofing Component Terminologies

It is vital to understand different terminology when it comes to roofing. This will help you to select the right products or warranties for your project. Here are some definitions to help you understand important terms about roofing.


A protective layer installed on a roof to protect the sheathing, waterproofing, or other layers.


Protective barrier designed to stop water from damaging roofs or walls.

Drip Edge

Section of flashing to direct water dripping from roof edges down to another surface, or away from walls.

Cripple Flashing

This is a fitting that’s used below the rafters’ top edges, or along the eaves. It prevents moisture intrusion in foundation walls when rainwater penetrates roof decking.

Verge Cap

Protect the fascia board on an exterior corner of two roof surfaces by placing metal, stone, slate tile or concrete pieces above the exposed front face of an eave.

Chimney Flash

The flashing protects water from getting into the attic through the joint of a chimney roof. The flashing is resistant to heat generated by the fireplace. It has a sloped base with a draining opening at the top for moisture.

Balloon Framing

A method of timber framing with curved timbers. The diagonal bracing provides rigidity, strength and support. The posts are raked in the middle between floors to create a dome effect that reduces structural stress during weather loads.


Asphalt, wood shingles, slate, and fiberglass shingles made from wood slats. The shakes are stapled horizontally with tabs on each end for nailing onto a roof deck. The shakes can be secured with nails set into the tabs. Asphalt shakes come with plastic beads embedded in each tab to prevent any leakage.


The ratio of the incline or fall on a roof surface expressed as rise/run: 2/12 equals 1/6 inch per pied (an 8′ section rises 24″); 4/12 equals 2/3″ per foot (16 inches for an 8-foot Section).


An exterior window structure extending from the roof plane of a building and featuring one or more windows on all four sides. Some dormers in certain regions are known as “balconies”.


The vertical walls that extend outward from the main roof of a building and support an overhanging story or stories are located at each end of its facade. Bracketing, commonly known as trimmers, attaches to the rafters to support the wall’s gable.


The wood- or metal molding is used to cover an interior or outdoor wall.


A board with scrolled decoration that is attached to a roof’s rake edge. The bargeboards are typically placed midpoint between adjacent gables. There may be only one or two barsge boards depending on the architecture style.


The ends of building roofing that extend beyond the exterior walls. Eaves are protected from rain through extending above the walls with eaves moldings known “rakes.” It collects water and directs it via gutters to a drain pipe or rain barrel.


A flat structural slate used as an overlay on roof decking materials. Wood shakes are used as roof decking materials. The use of tile prevents water from entering the interior spaces by preventing leakage through the roof. Depending on the thickness of the tile, it is waterproof to 5-15 PSI (pounds/square-inch). There are three main types, including two-ply membrane and modified bitumen.

Soffit Tray

A metal tray placed near the edges of buildings that collects water. The trough is used to allow water flow to the catch basin.

Catch Basin

This series of sections made from concrete or plastic pipe are attached to the base of rain gutters. This allows for water to be held in place so that it does NOT spill over onto your gutter system.


A pipe where water from the roofs of property runs down to ground. They run usually from the first story and are often attached to walls or corners so that water can drain into an exterior drain system.

Decorative metal shields

Decorative metal bands that are applied around the base of columns and posts to prevent vandalism or flanking emission.


The edge that defines the interior angle between each member in a truss. It’s also called “the web of the Truss”, but this term doesn’t apply because web implies something solid. In reality, these chords can be hollow rectangular tubes with holes cut through them along their length.


A planked wood or composite material is laid over joists in order to create a flat flooring. Cedar, redwood, treated and pressure-treated pin are all common decking material.

Roof Breech

The top part of most chimneys where smoke goes up draft is formed (creates suction for air to come into the chimney) when a fireplace or stove heats. If the top portion of a chimney is blocked (mostly by ice), heat cannot escape from the opening. That’s when backdraft occurs, which can lead to carbon monoxide poisoning.


A series-shaped construction that is attached to posts or columns. The railing consists of small balusters with open spaces between them. Balustrades decorate property with ornamental designs and help prevent accidents due to falling from balconies, stairways, or other places.


This involves placing stone slabs on top of each another in a decorative pattern that can be used to build architectural structures.

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