Alpha ProTech REX SynFelt Synthetic Roof Underlayment 10 Square Roll, Asphalt-Free Polypropylene

REX SynFelt is a 100% asphalt-free synthetic roof underlayment made of high-strength woven polypropylene with an anti-slip coating on both sides. One roll covers 10 squares and installs lighter, stronger and cooler than 30 lb asphalt felt. UV-resistant for up to 6 months of exposure, with a pre-printed nailing pattern.

Key Features:

• 20X Stronger: 20 times stronger than 30 lb asphalt felt and won’t tear off, buckle or curl when wet.
• 7X Lighter: 7 times lighter per square than 30 lb asphalt felt for easier handling on the roof.
• Two-Sided Grip: Anti-slip walking surface on both faces for additional installer grip.
• 10 Squares per Roll: Covers 10 squares per roll for fewer rolls and faster installation.
• 6-Month UV Rating: UV-resistant and can be exposed for up to 6 months.
• Nailing Pattern: Pre-printed nailing pattern speeds accurate fastening.

Specifications Table:

Coverage & How Much You Need:

Each roll covers 10 squares (1,000 sq ft) of roof deck. Divide total roof square by 10 and add rolls for laps, ridges and waste on cuts.

Fit and Compatibility:

Used as underlayment beneath asphalt shingles and other steep-slope roof coverings. Pair with drip edge, starter and ridge products; fasteners are sold separately. Complements other REX-line weather barrier products.

Frequently Asked Questions (FAQ):

Q: What is included?
A: One roll of REX SynFelt synthetic underlayment covering 10 squares.

Q: How many rolls do I need?
A: Divide your roof area in squares by 10, then add a roll for overlaps and cutting waste.

Q: How does it compare to felt?
A: It is 7X lighter per square and 20X stronger than 30 lb asphalt felt, and it won’t tear off, buckle or curl when wet.

Q: Is it slippery to walk on?
A: Both sides carry a specially formulated anti-slip coating for added grip.

Q: How long can it be exposed?
A: It is UV-resistant and can be left exposed for up to 6 months.

Q: Does it contain asphalt?
A: No, REX SynFelt is 100% asphalt-free.

Expert Verdict Reviewed by the SuperArbor Pro Desk

For steep-slope reroofs, synthetic underlayment like REX SynFelt is the safer choice: the two-sided anti-slip coating and lighter roll weight reduce installer fatigue and slip risk, especially on 6/12 and steeper pitches. The 10-square roll means fewer changes on large planes, and the 6-month exposure window is valuable when roofing phasing slips into wet or hot seasons. Follow the pre-printed nailing pattern and use cap nails where local code or the shingle manufacturer requires them.

Use fall protection and roof anchors on pitched roofs, and always wear slip-resistant footwear even on anti-slip underlayment.

Order REX SynFelt synthetic underlayment for a lighter, stronger 10-square roll on your next roof.