Flex-O-Vent

Flex-O-Vent is a universal venting material from Marco Industries. It is a polyester-based ventilation product, and it is the original product in the Marco ridge ventilation line. It is made for metal roofs, where it sits under the ridge cap along the ridge, as on a metal roof replacement with a new ridge cap.

The material is a non-woven polyester mat that stays open to airflow. It is sold as rolls, and the name on the product is Flex-O-Vent Universal Venting Material. The product belongs to the Marco Weather-Tite System, and it carries a 40-year limited warranty.

One size fits most panels. The material is cut to length on the roof, so one roll serves many panel profiles and ridge lengths.

Flex-O-Vent comes in four cross-section sizes. Each is made in a 10-foot length. Each size is matched to a maximum rib height.

• 1-1/2" x 3" x 10': rib heights up to 1-1/4"
• 1-1/2" x 2" x 10': rib heights up to 1-1/4"
• 1" x 3" x 10': rib heights up to 3/4"
• 1" x 2" x 10': rib heights up to 3/4"

The 1-1/2" versions suit taller ribs. The 1" versions suit ribs up to 3/4". Two widths, 3" and 2", are offered in each height.

Flex-O-Vent comes in 10-foot rolls and in larger 20-foot rolls. The 10-foot roll mirrors most ridge cap lengths, so a single roll covers one ridge cap length. Multiple packaging options are available. Each package holds rolls of the same size.

The net free area is 23 sq. in. for the 1" free-standing product. Effective net free area varies with product height, panel profile and installation methods.

Air permeability is above 760 cubic feet per minute. Air moves through the mat, and the fiber structure does not clog. Flex-O-Vent is clog resistant.

Polyester does not absorb moisture. Moisture that is absorbed can freeze and block ventilation, and that is the failure the material is made to avoid. The material also holds together to keep out pests.

Flex-O-Vent is made from a specially formulated polyester. The polyester is manufactured from recycled material. The product carries a made-with-recycled-material mark.

Polyurethane products expand as they soak up water and contract as they dry out. That cycle causes them to disintegrate and fail. Polyester does not take up water, so the material avoids that cycle. Marco gives Flex-O-Vent 40 years of Weather-Tite performance.

The material is flame resistant, tear resistant and durable. Physical test values are:

• Cold cracking: -55˚ C (-130˚ F)
• Compression strength: 1.8 psi at 75%
• Tensile strength: 16 psi, with elongation of 175%
• Tear strength: 3.5 ppi
• Abrasion: no damage

Flex-O-Vent is made in North America. The product mark is an EV logo with the name Flex-O-Vent.

Flex-O-Vent is held in place by a double bead of M63 adhesive. M63 is Marco's proprietary continuous double-bead adhesive. It holds the vent securely until the ridge cap is installed. The adhesive is key to quick, easy installation.

The ridge cap is then fastened at the major rib. The screw gun is set to at least 2700 rpm. The ridge cap compresses the material between the cap and the major rib.

The vent is cut with scissors or a utility knife. The cut is made on the roof, at the length the ridge needs. The 2" slot at the ridge is cut first when the panel is not pre-cut.

One installer can place Flex-O-Vent. The steps in printed order are:

1. Make sure the panel is free of dust and debris. If the panel is not pre-cut, cut a 2" slot at the ridge. Measure and mark where the ridge cap will sit on the panel.
2. Start from the end of the ridge. Roll out Flex-O-Vent along the length of the ridge, on both sides. The vent sits up-slope from the edge of the ridge cap.
3. Apply the ridge cap, compressing the material between the ridge cap and the major rib. Fasten at the major rib with a screw gun set to at least 2700 rpm.

Rolling the material out from the end of the ridge keeps the vent in one continuous run. The 10-foot roll length matches most ridge cap lengths, which keeps the cutting to a minimum.

The two heights are chosen by rib height. The taller version in each width fits panels with rib heights up to 1-1/4". The shorter version in each width fits panels with rib heights up to 3/4". Both heights are made in 3" and 2" widths.

The 10-foot roll fits most ridge cap lengths. The 20-foot roll is the larger option for longer runs.

Flex-O-Vent is one of three polyester ridge ventilation products from Marco. FlexPro is a profile-cut strip or roll made to fit most roof panels. LP2 Ridge Vent is a custom-cut vent strip with Python polyester vent material inserts. Of the three, Flex-O-Vent was the first in the line.