Choosing the right roof underlayment for critical roof failure zones

Roofing materials have come a long way over the years. While there is now a wide selection of materials to choose from for the primary layer (asphalt shingles, clay tile, metal, wood, slate), builders and homeowners are looking far beyond aesthetics. Cost, roof architecture, maintenance, climate, and lifespan should also be examined before making such an important investment.

Skilled roofing contractors know that the primary roofing layer will only perform to its fullest if the right underlayment system is chosen. Underlayment is a protective material installed under the primary roofing material to help protect it from moisture and air ingress. It also creates energy efficiency, as it helps prevents air and heat from permeating into or out of the structure.

The most critical zones on the roof for failure are roof ridge vents, valleys, and soffits. Choosing the right underlayment for these areas is critical. On the market today are three main types of underlayment, each with their own pluses and minuses.

TypeMaterial ComponentsProsCons
FeltFiberglass or organic felt saturated with asphalt
  • Inexpensive
  • Easy to install
  • Good for steep-sloped roofs
  • Not entirely waterproof
  • Wrinkles and tears easily
  • Can deteriorate with exposure to direct UV
Rubberized AsphaltRubber polymers with a self-adhering surface
  • Impervious to water
  • Self-sealing abilities that can seal spaces between nails and fasteners
  • Ideal for cold/snowy regions
  • Highest in material cost
  • Labor-intensive
SyntheticPolymers, polypropylene, polyethylene and fiberglass for strength
  • Highly durable
  • Resistant to UV penetration
  • Good for high temperatures
  • Long lifespan
  • Anti-slip qualities, making it safer to walk on
  • Appropriate for all slopes
  • Easy to install
  • May require cap nail fastening, adding to labor costs
  • Fasteners may increase the risk of water intrusion

Overall, synthetic underlayment offers the best of both worlds: price and performance for critical roofing zones. A strong synthetic underlayment begins with its film. That’s where leading cast polypropylene and polyethylene film manufacturer Profol comes in.

Profol’s line of building and construction films are comprised of polypropylene and/or polyethylene and have excellent toughness and chemical resistance. They also provide a good moisture and air barrier and can even offer anti-skid properties. Profol underlayment films provide a coatable surface for adhesives made from most any chemistry. Laminated films are also available that easily work with other substrates.

Designed to protect and increase lifespan, Profol’s synthetic underlayment helps insulate your structure and protect those areas most prone to water or ice buildup, such as roof ridge vents, valleys, and soffits. Located in the heart of Midwest USA, Profol offers attractive lead times and easy transportation.

Want to learn more about Profol’s synthetic underlayment or other building & construction films? Reach out to us (319) 731-3326 or email Scott Bruner at

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