Say what???

Siding terminology can be confusing, but once you are familiar with some simple words it all seems to make sense. Here are some commonly used terms...


Backer Tab: Provides support for non-insulated 8" siding at panel overlaps (joints), and behind panels at corners to ensure a smooth installation.


Butt Edge: Bottom edge of siding/soffit panel or accessory piece opposite the nailing slots. Locks onto the preceding panel.


Channel: Area of accessory trim or corner post where siding/soffit panels are inserted. Also refers to trim itself, and named according to letter of alphabet it resembles (i.e., J-channel, F-channel, etc.).


Course: A row of panels, one panel wide, running the length of the house from one side to the other or, in the case of vertical siding, from top to bottom.


D4 Profile:Two four-inch wide horizontal traditional planks per single panel of siding.


D5 Profile: Two five-inch wide horizontal traditional planks per single panel of siding.


Drip Cap/Head Flashing: An accessory installed with vertical siding to ensure that water drips away from panels and does not infiltrate them; it is also used as a vertical base.


Dutchlap or Shiplap: A more decorative variation on the clapboard style where the face (or width) of the board is beveled for added dimension.


Eaves: The lower, level part of a roof overhanging a wall.


F Molding (or Trim): Molding used for trim that is in the shape of the letter F, used to trim the edge soffit just above the vinyl siding, on the wall side.


Face: The part of the vinyl panel that is visible once the vinyl is installed Face Nailing: Action of fastening directly onto the face of panel, rather than using the nail hem slot. Generally not used in siding installation.


Fascia: The trim piece nailed to the ends of a series of rafters or trusses to tie them together at the lower, level end of a roof. The fascia supports the sheathing on the edge of the roof as well as the front edge of the soffit.


Fascia Board: The exterior finish nailed to the fascia that is nailed to the rafter or truss ends that runs horizontally around the roof on which the gutters are mounted. The fascia board forms a drip edge for rain water, as well as hides the end of the roof sheathing and soffits.


Flashing: A type of sheet, usually a metal like aluminum, used at intersections of building components to prevent water penetration, flashings are commonly used above doors and windows in exterior walls and are used under the siding to prohibit water penetration.


F-channel: A manufacturing component of vinyl or aluminum siding systems which have a channel that the planks fit into, used around windows and doors to make a weathertight seal.

Furring/Furring Strip: A wooden or steel framing material, usually 1" x 3", used to provide an even nailing base. To “fur” a surface means to apply these strips.


Gable: The upper triangular-shaped portion of the end wall of a house.


Inside Corner Post:Provides a means of joining at inside corners where siding butts both sides.

J-Channel: Also J Molding (or Trim): Molding used for trim that is in the shape of the letter J, used to trim the edge of siding on all sides of windows and doors, at rake edges of gables and in other miscellaneous situations.


Lap: To overlap ends of two siding panels to allow for expansion and contraction of siding product.


Lap Siding: Technique for installing horizontal siding boards. Each piece of siding is 'lapped' over the piece below it to provide a waterproof covering for the house.


Nailing Hem (or Flange): The section of siding or accessories where the nailing slots are located.

Outside Corner Post: Provides neat appearance outside corners for vertical and horizontal sidings. Receives siding from both sides. Deeper post is used with insulated siding, and narrower post with non-insulated siding.


Positive Lock: ensures that the panels can be locked together, but can also easily slide back and forth for ease in installation. This ensures that the panels stay permanently affixed during adverse weather.


Plumb: A position or measurement that is truly and exactly vertical, 90° from a level surface.

Profiles: The actual siding panels are called profiles. Some commonly sized profiles are D4, D5 and Dutchlap.


PVC: Polyvinyl chloride is the material used to create most vinyl siding.


Rake: The edge of a sloped roof forming the overhang beyond the wall of a gable roof or other sloped roof.


Soffit: The underside of elements of a building, such as overhangs, staircases and beams. Also referes to the material used to enclose the horizontal underside of an eave, cornice, or overhang. Some soffit panels may also be used as vertical siding.


Square: Unit of measure for siding equal to 100 square feet (or a 10-foot by 10-foot wall section).


Square Feet:(also known as Exterior Square Feet) Exterior Square Feet is a term used to denote the total amount of siding material needed for a particular siding job including material waste.


Starter Strip: Baseline accessory which secures the first course of siding to the wall. Used with horizontal and vertical siding.


Tongue and Groove (T&G): Tongue and groove, a connection system between components, like wood, in which the tab or tongue of one board is placed into the grove at the end of another board.


Wall Cladding : Another term for siding.


Wall Sheathing: Sheets of plywood or wood planking used to cover the wall framework of the house. This is the material that the siding is nailed to.


Weep Holes: A small hole in the bottom butt edge of the vinyl siding panel, or other accessories, allowing condensation to escape.


Windload Pressure: Is a measurement of how well a panel might perform in high wind areas.

Window Head Flashing: Possible alternative to J-channel to receive siding over doors and windows and as a base flashing on vertical siding installations.