Installation Instructions
CertainTeed Vinyl Siding Installation Guide
32
When covering over masonry or bricks, it’s better to use 1" x 3" 
furring. For best thermal performance, install a minimum 
of 1/4" foam over furring strips. 
Furring and/or foam is also used below eaves and windowsills to 
maintain correct slope angles when siding panels must be cut to 
a narrower dimension to fit.
Similarly, when panels are cut to fit over doors or windows, furring 
and/or foam is used to establish the correct slope angle.
Applying over stucco or masonry
When applying vinyl siding over stucco or masonry, you first 
have to be sure you’re working on an even surface. To create 
that surface, you may have to knock down high spots where 
furring strips will be applied. Use caution when chipping off these 
spots—you don’t want to crack or damage the remaining stucco 
or masonry.
Apply 1" x 3" furring over the stucco or masonry using power-
actuated fasteners or other appropriate masonry fasteners. 
Stucco will not hold fasteners tightly, so be sure nails or screws 
are anchored securely to studs. Furring strips should be spaced 
16" on center.
Applying rigid foam sheathing to furring
Install sheathing according to manufacturer’s instructions. 
Do not apply siding directly to furring strips. For best thermal 
performance, install a minimum of 1/4" foam over furring strips.
sill
undersill trim
J-channel
siding
siding
J-channel
sill
Furring strip/foam shim
furring strip/foam shim
stucco
16"
1" x 3" furring
masonry 
fastener for 
attaching 
furring
foam 
sheathing










