If I use pressure-impregnated treated shingles do they require ventilation or special spaced sheathing?
No they do not. Standard shingles tend not to last as long on unvented sheathing; ventilation should be provided on solid sheathing for the best results. Please consult the CSSB's New Roof Construction Manual for more information.
Is it necessary to have ridge vents on a cedar roof?
If you have an area between the roof and the sheathing ridge and no other ventilation had been provided, ridge vents are a good idea.
Do I need to use a ventilation product under my Certi-labelTM shingles?
Good ventilation is essential and can be achieved in a variety of ways; check with your Approved Installer to see if nailing strips (spaced sheathing) or a continuous ventilation product is the best choice for your roofing project. Both choices are effective, however the nailing strips (spaced sheathing) are typically ¾" thick and the ventilation product is usually ¼" thick: if the rafters are very long the nailing strips (spaced sheathing) will provide more air circulation.
How do I ventilate a steep slope ridge area?
On steep slope roofs, the correct ridge vent products can actually facilitate the ease of installation of Certi-labelTM ridge units. Always follow the manufacturer's installation instructions. The predominant ridge material manufactured today is for a medium slope roof. However, by using a ridge vent that is pliable and at least 8 ½" 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 vent material to the Certi-labelTM shakes or shingles. Proper nailing of the ridge units will create a serviceable application.
Is the ventilation product warranted?
Please contact the manufacturer of the ventilation product for warranty details. The CSSB does not administer warranties for any type of ventilation product.