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General Roofing Terminology

Below you will find the major roof components illustrated and briefly defined.


A long piece of wood or steel that supports your roof.


The overhanging part of the roof that sticks out your walls.


The degree of weather protection offered by a roofing material. Most common are asphalt shingles, wood shakes, metal roof, tile or slate.

Decking or Sheathing

Normally plywood which provides a flat surface covering your home.


A gabled extension protruding from a sloping roof to allow for a framed window.

Dormers are essentially the structure around a window that projects from a sloped roof. This structure is set vertically on the roof slope and has its own roof.


Shape, layout and slope of roof for shedding snow and water.

Drip Edge

It is a piece of metal, plastic or vinyl that is nailed at the bottom of the roof edge, or eaves to facilitate proper water drainage. It allows for the water to drain into gutters or cleanly off the roof rather than running down the roof edge and down the fascia, which will eventually lead to rot. The drip edge is one of the first things attached to the roof and should be installed underneath the roofing, felt with about inch of overhang extending past the fascia and hanging just over the gutters. A drip edge can range in materials and thickness.


Parts of a roof that project beyond or overhand the face of the wall at the lower edge of the roof.

Eaves Trough

They are also known as gutters. They provide a method by which water that drips off the roof is caught and carried down the down spouts to an appropriate area for it to wash away.


Specifically, exposure to weather.


The Fascia is attached below the roof line and connects to the soffit, and often where the gutters are attached to the house.


It is a building paper of strong, tough base saturated with asphalt.


Pieces of metal used to prevent the seepage of water around any intersection or projection in a roof such as vent pipes, chimneys, valleys and the joints at vertical walls.


The end wall of a building which comes to a triangular point under a sloping roof; also known as a type of roof.


An external angle formed by the meeting of two sloping ends of the roof, from the ridge to the eaves; also known as a type of roof.

Pipe Vent

A vertical pipe of relatively small dimensions which protrudes through a roof to provide for the ventilation gases. In some cases, after roof surface is installed the vent pipe is covered with roof vent. This technique is lead to a nice and aesthetic finish.

Rafters / Trusses

Main framework of all roofs, usually grouped in a triangular nature that support the roof. Part of the roof truss. Rafters rest on the top of the building wall and are inclined up to meet the ridge or another rafter which they are fastened to. Rafters will be spaced every 16-48 inches depending upon the design of the roof. The rafter will often extend beyond the wall (overhang) which creates the eaves of the building to help protect the siding and windows of the buildings as well as make sure that water from rain and/or snow will run off the roof farther away from the foundation of the house.

              Common Rafters - Common to all types these beams extend at right angles from the plate to the roof ridge. They are                  used as the basis for laying out other rafter type. 

              Hip Rafters - The roof beams that extend from the corner of the plate to the ridge.

              Valley Rafters - The roof beams extended from the plate to the ridge along with intersection between two roofs.

              Jack Rafters - /hip/ roof beam that extends from the plate to the hip rafter.

                                   - /Valley/ roof beam that extends from the ridge to the valley

                                   - / cripple/ roof beam that is placed between a hip rafter and a valley rafter. it does not touch the ridge or                                       the roof or the plate. 


The inclined edge of a pitched roof over an end wall.


It is the highest point of the roof that runs the length of the roof. Ridge is where the sides meet to form an angle and must be covered with a ridge cap to keep water away from making its way into the attic.

Ridge Vents

/vented ridge caps/ are often installed to help with ventilation of the attic, and may run the length of the ridge. These vents allow warm air to escape the attic draws cool air in through vents in the soffit. An important part of keeping the attic temperature nearer the outside temperature ridge vent helps protect against moisture buildup and ice dams.

Ridge vents are normally covered by the ridge cap to maintain a consistent appearance, and is visible on the top the roof.


It is the horizontal area under the roof overhang when it has been closed off for a more finished appearance. It covers the area between the end of the eaves and the house.


The amount of roofing material required to cover 100 square feet (10' x 10') of roof surface.


A layer of moisture protection between the decking and exterior roof covering. In northern climates an MFM Ice and Water Shield helps to minimize ice damage problems.


Is defined as the area where two roof fields join making an upward angle.

Roof Valleys as a very common area of failure in a roof and it is important to take care of the valley(s) of your roof by making sure that branches, dirt, leaves etc..are not allowed to collect. When this happens, drainage is impeded, and water can begin to back up under the shingles eventually causing a leak. The best method is by using metal flashings which will typically result in a longer lasting roof.


Is the measure of how "Steep" a roof is? For example, if a roof id 4 on 12" the roof rises 4 inches fir every horizontal run of 12 inches. The pitch of the roof is a being factor in determining the kinds of materials that can be used and the longevity of the roof. Usually, a steeper roof (higher pitch) will last longer due to its better drainage capabilities.

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