Roofing Terminology


Philadelphia Roofing Glossary


A strip of asphalt material along the rake over an unseen drip edge metal. 


a metalworking machine that allows the bending of sheet metal. A cornice brake only allows for simple bends and creases, while a box-and-pan brake also allows one to form box and pan shapes. It is also known as a bending machine or bending brake   


The term where felt {tar paper} has had UV rays of the sun deteriorates the roofing and actually burns a hole through it. This is seen on cedar shake roofs allot when a cedar shake has split or worn away leaving the felt exposed and soon after that the sun burns a hole through the felt.
A composition shingle made of asphalt and fiberglass mat with ceramic coated granules embedded on the surface. Superior products have reinforcement weave also in the asphalt too insure a high performance shingle. Here a roof done with GAF Grand Sequoia done by my company years ago as seen by the old packaging.
Class A, B or C  
A classification given by laboratories that test roofing products for fire ratings. All roofs being applied must meet a minimum class C fire rating in California. Most asphalt shingles and tile roofs are rated at A. Metal roofs can achieve a A, or a B rating and Cedar Shakes can be A, B and most commonly Class C ratings.
This metal strip serves as a water diversion, to move the water on the roof away from a opening where gutters cannot was not installed. This metal is 12 x 2 inch high x 10 foot long. The 12 inch part is installed under the shingles and must be maintained if you have trees near the home, but is a great way to keep water dumping into this open area.
Double Felt
Double felting a deck is done typically on low sloped roofs under 4 and 12 pitch where roofing is to be applied. Here is an example of a 3.5/12 pitch front porch having a first ply of 30/36 felt then the shake liner at 10 inch exposure for cedar shake application. Once up past the porch the roof becomes 4/12 pitch and the double felting is not required over the skip sheathing.
The vertical trough connected to the gutter to remove water from it.
A small gable or shed roof in the middle of a larger roof {see #1}
Dormer Vent
A sheet metal exhaust vent installed on top of the roof to ventilate the attic. This should be installed no lower than three from the ridge.
Sagging of the roof framing members on this old garage. This normally is caused from poorly installed solar ties or wall joist. The rafter literally pushes out the walls at the top plate as the weight of the roof squats downwards.
Dry Rot  
Deterioration of wood fibers caused by moisture intrusion for a long period of time. Many times dry rot on the roof can go undiscovered for years. That is why roof tear offs are so important to do and not a recover. Here is where application of Grace Ice and Water Shield would have saved the rake edge.
Dutch Gable
A combination of a hip style roof and a gable. {see 2}
The area of roof that overhangs the lower edge.  
Eave Vents
Small screens under the eave that allow fresh air to enter the attic.  
This term is used for the area of roofing material that is exposed to the weather.
This is some times call “tar paper” and is a moisture barrier to protect the roof deck. This is used in most roofing systems.  
A corrosion resistant metal designed to terminate roofing at walls, chimney’s or penetrations through the roof. The bare metal before painting would glare in the eyes of a roofer and flashes of sunlight originates this name.
Fascia {Fay-sha}
The horizontal board attached to the eaves rafter tails
Fiber Cement Shakes/Slate
A class A roofing material designed to look like shakes made with Portland light weight cement and wood fibers.
Rain gutters are attached to the eave of the roof and catch rain water, controlling the roof drainage run off.
The triangular roof shape at the end of a building {see#3}  
High Definition Ridge
A fiberglass roofing product made for hips and ridges on asphalt shingled roofs. Always use proper nail length since there are multiple layers of roofing here and the thickness of the ridge cap. I prefer hand nailing to pneumatic because of this.
The convex junction of two adjacent roof plains. {see # 3}  
A ceiling is nailed to this framing members. These are also used to tie walls together.  
Delivering the roofing material from the street to the rooftop by conveyor.
Modified Bitumen 

Low sloped roofing product sold in rolls usually applied with a torch.
Nosing or Drip Edge
The pre-fold edge metal installed along the eaves and rakes of the roof.
2″ x 4″ framing to support a barge rafter, here seen unpainted. This are also called Look Outs.
An alternative to plywood used for roof decking. Oriented Strand Board is made from wood chips oriented and gued in layers. It is heavier than plywood becuase there are no voids. This makes a great roof deck because of it’s density and shear value.  
The slope of a roof. The term four and twelve means four inches of rise in a twelve inch span.  
A brace placed in the attic to support the rafters.
Sheets of thin flat wood laminated together into four by eight foot sheets used for roof decking.
The edge of a gable
The framework the the roof decking is nailed to.
The top or peak of the roof. {see  #4}
Roof Jack
A corrosion resistant metal covering that seals penetration on roof such as exhaust fans, gas water heater pipes and plumbing venting through the roof.
Seal Coating
A roof coating is a monolithic, fully adhered, fluid applied roofing membrane. ... This means a roof coating actually becomes the top layer of a composite roof membrane and underlying system.
Solid Sheeting
This term is for describing a solid deck that has timbers with no gaps, plywood or OSB on it.  
Shinglers use this word for a wall with cedar shingles applied to it.
Skip Sheeting
Typically 1 x 4’s spaced sheathing is used when cedar shakes and shingles are installed so they can breath. Shakes are 24 inch applied here at 10 inches to weather and must have felt paper interlaced with the shakes. Cedar shingles are thinner and 18 inch. Exposure here is 5 inches and originally would not use felt since the lay out is tripled. Check your local building department for local code requirements.
A Square
The term square is used as a roofing measurement. 100 square feet or ten by ten = a square. The average home is about 28 squares.
Step Shingles
A corrosion resistant peice of metal that is bent to a 90 degree angle weaved into the shingles at walls, skylights and chimney’s.
Tar and Gravel
3-plies of roofing material hot mopped in layers to the roof deck primarily on low sloped roofs below 2 and 12. This is covered with gravel to protect the roof material from UV sun rays.
Clay or Concrete
Here a mission clay, cap and pan installation over a modified roofing system on a lower sloped roof.
Torch Down
Roof (Single Ply or Modified Bitumen) A newer roofing material mostly used on flat roofs. This material usually comes in rolls and is applied to the roof with an open flame or 'torch.'
Tubular Skylight
A natural light system using a reflective tube to carry the light into the home.
This is some times called a whirly-bird and is used to exhaust hot attic air.
A deck protection under most roofing systems.
Junction where to roof plains meet and water flows too. {see #5}
The term is used to describe the system to provide movement of fresh air into and out the attic.
White Granulated Rubber Roof
A rubber roofing material usually applied with a torch.
This is a termination bar that step shingles are designed to slip under.

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