Owens Corning

1. Determining Ventilation Requirements

Determine the total required length of the ventilation slot according to the 1/150 rule (1 sq foot of ventilation area for each 150 square feet of attic floor). For a balance system, no more than 50% of the required ventilation should be installed at the ridge or hips.

2. Ridge Ventilation Slot Preparation (fig. 1)

Determine the type of roof framing that is used under the roof sheathing.

For roofs with a ridge board, cut a 1 inch slot in the roof sheathing beyond each side of the ridge board.

For an engineered truss roof, cut a 1 inch slot on each side of the ridge (total slot width of 2 inches).

Important: Start and end your cut 6 inches in from the rake edges

Note: The slot may be pre-cut on a new roof before or after shingle installation, or in a retrofit the slot can be cut from the pre-shingled roof using a circular saw with a carbide tip blade (protective eye goggles should be worn during this process.)

Fig. 1

3. End Cap Installation

Pull off a pre-cut section of the foam end cap found in the vent. (fig. 2) Using a utility knife, make a (fig. 3) Insert the foam end cap with the cut-back vent fabric between the foam end cap and the underside of the vent to assure a weather tight seal. (fig. 4).

Fig. 2-4

4. Apply Asphalt Roofing Cement

With the shingles installed and the slot opening exposed , install a bead of asphalt roofing cement below the vent slot opening on each side of the ridge, and at each end. The sealant should run the entire length of the ridge and should “picture frame” the slot. This will help fill in any gaps between the vent and the shingles, particularly when using laminate shingles (fig. 5)

Note: Sealant must be applied to roof shingles before installing vent. Use asphalt roofing cement complying with ASTM D4586

Fig. 5

5. Vent Placement on Ridge

Roll out VentSure® Ridge Vent along the entire length of the slot also covering the 6 inches minimum uncut ridge on both ends. Bend vent into a “V” shape. Secure at the lead edge after inserting the end cap. Attach vent to the roof deck by driving a nail in each of the two corners of the vent. (fig. 6) Also, drive two nails through the vent and foam end cap to hold foam in place on the ends of the ridge only.

Note: Nails must be corrosion-resistant, 11 or 12 gauge, with heads at least 3/8 inch in diameter. All fasteners must be flush with the vent surface and penetrate Pull the vent tight and secure at about 10 feet. Pull the rest of the vent tight and secure, inserting the end cap as stated in step 3. Multiple lengths of vent can be joined by butting the sections tightly together with a bead of sealant on top of the joined pieces. End caps should be inserted at the beginning and end of each section. There is no need to pre-fasten VentSure® Ridge Vent prior to cap shingle application.

Fig. 6

6. Cap Shingle Installation (fig. 7)

Secure cap shingles and vent at the same time according to the cap shingle manufacturer’s installation instructions. For the fastest installation, a coil nail gun can be used as long as the penetration requirements are met. It is important when installing this vent that you maintain the pitch of the roof. The vent has been installed properly if the bottom of the vent is flat on the roof and the peak is slightly rounded.

Note: VentSure® Ridge Vent can also be used on Hips. See Owens Corning website for instructions.

Fig. 7

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