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Vinyl Siding Terminology


Common terms to know for following along the installation instructions:

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The contour or outline of a siding panel as viewed from the side.

Nail flange

Flat area along top of panel with slots for nailing; slots allow for expansion and contraction.


Molded area just under nailing flange into which butt leg/locking leg of next panel above is secured.


The width of the exposed face of each panel of siding; also referred to as reveal.


Visual and tactile characteristics of the siding panel; designed to recreate the authentic look of natural wood grain, stucco, smooth painted clapboard, etc.

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Panel Thickness

An important element of siding quality. Thicker panels are more durable, stand up to impacts and high winds, and look straighter on the wall.

Butt leg/locking leg

The bottom part of a siding profile that connects or locks into the panel below.

Panel projection

Common to products with multiple faces (i.e. Double 4 or Triple 3). It is the dimension required for the proper selection of receiving channels (e.g., J-Channels and corner pieces).

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