77 Ill. Adm. Code 870.170
Perimeter Enclosures
Section 870.170Â Â Perimeter Enclosures
a)Â Â Â Â Â Â Â Â Material
and Ventilation. The perimeter enclosure material shall be of material
manufactured for this purpose. The material must be installed in a manner that
will not allow water to be trapped between the perimeter material and the
siding or trim to which it is attached. The perimeter enclosure material is to
be vented according to the manufacturer's recommendation to prevent moisture
buildup. If the manufacturer's specifications are not available, to assure
proper ventilation, the open area of the vents must be equal to at least 1/300
of the floor area of the home.
b)Â Â Â Â Â Â Â Â Installation.Â
Perimeter enclosure material must be installed to accept possible frost heave.Â
The perimeter enclosure must be installed to the manufacturer's
specifications.
c)Â Â Â Â Â Â Â Â Access.Â
A utility inspection panel that can be opened without the use of tools and that
is a minimum of 24 inches by 18 inches must be provided.