WeatherLock® Flex

WeatherLock® Flex installed between the roof deck and the roofing helps prevent damage caused by wind-driven rain and ice damming. This exclusive Owens Corning® product is a self-adhesive roofing underlayment for asphalt shingles, wood shakes or quarry slate roofs.

Precautions:

• Read and understand all instructions and precautions before applying WeatherLock® Flex.
• Check local building codes prior to the application of this product.
• Follow the recommendations of the roof covering manufacturer and the Asphalt Roofing Manufacturer's Association.
• WeatherLock® Flex is intended for use on roof slopes of 2:12 and greater only.
• When installing WeatherLock® Flex over the entire roof deck, proper ventilation is required. Consult a design professional and local building codes for ventilation requirements.

Roof Deck:

Ensure the decking substrate meets the requirements of the roof covering manufacturer and local building codes.

• 6 inch minimum roof deck board width, minimum 3/4 inch thick, with minimum 1/8 inch spaces between boards.
• Minimum 3/8 inch plywood.
• Minimum 7/16 inch OSB (Oriented Strand Board).

Deck spacing cannot exceed 1/4 inch between roof boards or between plywood or OSB. Follow local building codes.

Deck Preparation:

1. WeatherLock® Flex can be applied on new construction or when reroofing, provided existing shingles and underlayment have been removed. Remove all old roofing down to the deck, or in new construction, apply over the new deck.
2. Sweep the deck surface to remove dirt and debris. The deck must be clean and dry before applying WeatherLock® Flex. Replace any damaged or rotted deck boards. No primer is necessary.

Eaves Preparation:

1. WeatherLock® Flex should be applied over the metal drip edge at the eave unless otherwise permitted by local building codes. Ensure metal drip edge is nailed properly.
2. WeatherLock® Flex should be applied under the drip edge at the rake.

Step 3

Along a valley, WeatherLock® Flex can be installed in valley as a valley liner. For maximum protection, the roll width should remain intact and extend 18 inches on either side of the valley. Peel back the release liner sheet and press the underlayment into place working from the center of the valley or ridge outward in each direction. Always apply valleys starting at the low point and work upwards. If an overlap is needed be sure to over lap the previous piece by 3 inches. The underlayment should be applied in valleys before doing eave applications with membranes.

Step 4

WeatherLock® Flex should extend from the eaves to a point 24 inches inside the exterior wall. This will place the underlayment well above the maximum ice dam build-up line in most areas. Consult local building code for specific requirements.

Step 5

Extra courses should be installed using the same application instructions as described in sections 1 and 2. Overlap the second course onto the first course, 3 inches to the marked ply line. The lap area must be firmly hand rolled to ensure a water tight bond, adhesive is not required. Continue this same application procedure for additional courses, as needed.

Step 6

Overlap at least 6 inches when the ends of two rolls meet.

Step 7

Cover WeatherLock® Flex with finish roofing material. Do not allow the underlayment to remain uncovered more than 30 days. Prolonged exposure to wind, sun and weather will adversely affect this product’s installation and performance.

1. WeatherLock® Flex should be installed by a professional roofing contractor. The underlayment is designed to be covered by asphalt shingles, wood shakes and quarry slate roof assemblies. Protection from sunlight is required to ensure its long-term performance.
2. Limit foot traffic on WeatherLock® Flex as much as possible. Inability to do so may adversely affect this product's performance
3. WeatherLock® Flex is a moisture and vapor barrier. Since ice build-up is partially a function of ventilation, the spaces under the covered deck area and the attic space must be ventilated in accordance with local building codes.
4. WeatherLock® Flex is intended for exterior roof application only.
5. Apply WeatherLock® Flex directly to the wood deck. Do not apply shingle underlayment beneath WeatherLock® Flex.
6. Shingles should not be installed over wrinkled or buckled underlayment.
7. For fastening shingles, use galvanized steel, stainless steel or aluminum nails minimum 12 gauge shank with 3/8 inch diameter head. Fasteners that comply with ASTM F1667 are recommended. Check local building codes.
8. Use extreme caution when installing underlayment. The underlayment surface may be slippery even when dry. Use a fall protection system when installing. Consult OSHA for Guidelines on Fall Protection (20 CFR 1926.500).
9. For best results, apply WeatherLock® Flex when the air temperature is over 40ºF (4.4ºC) but below 100ºF (37.7ºC). When temperatures are under 40ºF (4.4ºC), underlayment will not fully adhere until warmer temperatures. Store at room temperatures prior to installing product in cold weather. If applied in temperatures above 100º (37.7ºC), it may become difficult to remove the release liner. If this situation should occur, move product into a shaded area until the underlayment is cool. Once cooled, the release liner can be easily removed.
10. Store WeatherLock® Flex in a dry, well-ventilated area. Stand underlayment upright. Do not store at 90ºF (32.2ºC), or warmer for extended periods of time. When applying underlayment, always follow local building codes and the shingle manufacturer’s instructions for installation of its product.

For Technical Inquiries, please call 1-800-GET-PINK® (1-800-438-7465).