About GAFGLAS® Ply 4

Constructed with a strong glass fiber mat coated with the finest quality asphalt, this base sheet is designed with optimum porosity to assure a sound, watertight membrane. It has a high tensile strength and high degree of dimensional stability, resulting in a roof system with greater resistance to splitting and cracking. Typical system guarantees available for up to 15 years; select system constructions available with up to 20 year guarantee coverage.

  • Optimum felt porosity provides ready escape of air while allowing proper asphalt penetration at the time of mopping
  • Meets ASTM D-2178, Type IV specifications
  • Can be used in all climate zones Rolls out flat for easy installation  

Features and Benefits

Product Documentation

Resources for every professional


We’re building new plants for greater capacity, and better systems for faster response and greater visibility.
Contractor Resources

Architects & Design Pros

We’re building better, faster, more accurate access to the information you need.
Design Resources

Property managers & owners

Whether you manage one property or many, we’re building the products and programs you need to reroof, restore, or maintain your investment.
Building Resources