Cor-A-Vent Product Guide

Figuring Your Ventilation Needs: V-600E: Square footage of building footprint X . 48 = Lineal Feet V-600E needed 20 V-300: Square footage of building footprint X . 48 = Lineal Feet V-300 needed 13.5 Example: 25' x 50' = 1250 Sq.F. 1250 x .48 = 600 600 ÷ 20 = 30 L.F. V-600 needed The above formulas will give the amount of COR-A-VENT ridge vent needed for a 1/150 vent ratio, provided an equal or greater amount of soffit venting is used. For a 1/300 ratio, (building code minimum) use half the amount of ridge vent. Note: Code interpretation may vary. Consult your local building dept. For the best appearance, install COR-A-VENT continuously the entire length of the ridge. This material may be duplicated only for the purposes of specifying COR-A-VENT products. No permission is given to duplicate or otherwise copy this material for any other purpose without the express written permission of COR-A-VENT, Inc. © 2005 COR-A-VENT, Inc. Balanced Ventilation Sheet 12/14 Note: Should you need any assistance in designing your ventilation system, fax or mail a sketch and information to our technical services department. COR-A-VENT will respond with recommendations for your particular building design. COR-A-VENT ® has promoted and taught balanced ventilation from the day we started. It’s a concept all vent manufactures readily endorse. Unfortunately, that information doesn’t always end up in the hands of the person designing the building or installing the vents. Balanced venting helps insure the performance you expect from ridge venting – uniform, increased airflow through the roof cavity without weather infiltration. Balanced venting: An equal or greater amount of vent opening (sq. in net free vent area/NFVA) in the soffit (intake) than at the ridge. For example, our V-600 products have 20 sq. in NFVA per lineal foot. To balance this, you need 2 soffit/eave/intake vents of approximately 10 sq. in. per lineal foot ( 1 / 2 of 20 in each overhang). Balanced venting: Continuous soffit vents are recommended, especially for venting cathedral ceilings. Wherever there is ridge vent above, there should be soffit/eave/intake vents on the structure below. Also, COR-A-VENT strongly recommends using of one of our V-300 products (available in 11, 8 1 / 2 or 7" widths) on cathedral ceiling and hip roof applications. V-300 delivers 13.5 sq. in net free vent area. The volume of space to be vented in cathedrals is smaller. Therefore a lower profile ( 5 / 8 ") vent is called for to further reduce the chance for infiltration. When installing a ridge vent system, all other vent openings (except soffits) must be closed off. USE BALANCED AMOUNTS OF SOFFIT VENT TO RIDGE VENT Continuous aluminum strip vent – 8-9 sq. in. NFVA per lineal foot. 8" x 16" under eave cornice vents with maximum spacing of 4' apart – gives 14 sq. in. NFVA per lineal foot. Continuous perforated panels – 1' wide overhang (typical) – gives 12-13 sq. in NFVA per lineal foot. COR-A-VENT’s S–400 Continuous Strip Vent – 10 sq. in NFVA per lineal foot. Maintaining an unrestricted air passageway between the soffit and ridge is crucial to the performance of the vent system, and must not be blocked or restricted. COR-A-VENT recommends a minimum 2" air space between the roof sheathing and vent chute or insulation 1. SKYLIGHTS 2. DORMERS 3. INTERSECTING BUILDING COMPONENTS 4. VALLEYS 5. CHIMNEYS 4' MAX Typical continuous soffit vents The following NFVA values are approximate, except for COR-A-VENT S-400 strip vent. Consult the vent manufacturer or distributor for actual values for specific products. Typical Vent Chute Applications Typical Gable Knee Wall Cathedral Ceiling Balanced ventilation – The right proportion of venting. INLET (BALANCING) VENTS RIDGE VENT UNBALANCED VENTILATION AREAS COR-A-VENT, Inc. • P.O. Box 428 • Mishawaka, IN 46546-0428 Phone: (800) 837-8368 • Fax: (800) 645-6162 info@cor-a-vent.com • www.cor-a-vent.com ®