Installation Guide

Figure 16: Ridge Ventilation Detail
Airflow
through
ridge
Caulking
Roofing felt
®
Certi-Ridge
shake or shingle ridge
Ridge ventilation
product installed to
manufacturer’s
specifications
Felt folded back
Ridge Vents
Low Slope (6:12 or less)
Steep Slope (8:12 or greater)
Severe Climate Areas
The amount of venting depends upon the size
of the roof, roof design/structure, (attic present
or not, etc.) as well as local climatic conditions.
Check with your local building official for
requirements in your area. One rule of thumb
for venting the attic area is 1 square foot per
150 square feet of floor area. One half of this
(1/2 square foot per 75 square feet of floor
area) amount should be in the soffit or eave
and one half (75 square feet) in the roof
system. In the case of a balanced system 1
square foot per 300 square feet of floor area
may be adequate ventilation. Check with your
local building official.
The CSSB recommends the installation of ridge
ventilation product that allows for installation of
pre-manufactured ridge applied over the vent
material. There are many manufacturers of this
design.
On steep slope roofs, the correct ridge
ventilation products can actually facilitate the
ease of installation of Certi-label ridge units.
Always follow the manufacturer's installation
instructions. The predominant ridge material
manufactured today is for a low slope roof.
However, by using a ridge ventilation product
that is malleable and at least 8 1/2“ wide, the
material can be installed across the minimum 3”
of air space at the ridge to create a shallowing of
the slope at the ridge. Care must be taken to
caulk the ridge ventilation material to the
Certi-label shakes or shingles. Proper nailing of
the ridge units will create a serviceable
application.
In all wind driven snow areas, the proper ridge
ventilation product should have a screening
effect to prevent snow infiltration (not louvered
or baffled).
VENTILATION DETAILS
Architect: Gaylord Granger, Libby O’ Brien-Smith Architects, Photo: Eduardo Calderon
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