Installation Instructions
CertainTeed Vinyl Siding Installation Guide
13
SECTION 3 — Vinyl Soffit and Ventilation
Features of Vinyl Soffit
Butt Leg / Locking Leg
Molded area at bottom of 
panel that is snapped into lock 
on adjacent panel for secure 
connection.
Panel Thickness
An important element 
of soffit quality. Thicker 
panels are more 
durable and are less 
prone to sagging.
Panel Projection
Common to products with 
multiple faces (i.e. Triple 3). It is 
the dimension required for the 
proper selection of receiving 
channels (e.g., J-channels and 
corner pieces).
Nailing Flange
Flat area along top of panel with 
slots for nailing; slots allow for 
expansion and contraction.
Lock
Molded area just under nailing 
flange into which butt leg/locking leg 
of adjacent panel is secured.
Exposure
The width of the exposed 
face of each panel of soffit; 
also referred to as reveal.
Profile
The contour or outline of a soffit panel as viewed from the side.
Texture
Visual and tactile characteristics of 
the soffit panel; designed to recreate 
the authentic look of natural wood 
grain, stucco, smooth, etc.
Solid Soffit
Invisibly Vented Soffit
Fully Vented Soffit
Center Vented Soffit










