CertainTeed's DiamondDeck® High Performance Synthetic Underlayment is manufactured to provide best-in-class performance in terms of both weather protection and contractor safety.

DiamondDeck is a synthetic, scrim-reinforced, water-resistant underlayment that can be used beneath shingle, shake, metal or slate roofing. It has exceptional dimensional stability compared to standard felt underlayment.

Felt underlayment can wrinkle when it becomes wet and "telegraph" those wrinkles through to the shingles applied over it. DiamondDeck eliminates this problem and its special top surface treatment provides excellent slip resistance, even when wet.

Technical Information

  • Lightweight – Easy to work with and carry
  • Excellent tear resistance – Durability, reduced puncture risk
  • Superior wet/dry traction – Work faster and safer
  • Cool gray surface color – More comfortable working environment
  • Meets physical properties requirements of ASTM D226 and D4869
  • Length: 250 ft.
  • Width: 4 ft.
  • Miami-Dade Product Control Acceptance: Please see the Notice of Acceptance (NOA) to determione approved products by manufacturing location.


Applying a roof system correctly is essential to the warranty and performance of the roof. Please refer to the installation instructions for complete details. Available in both English and Spanish.

Warranty Details

When DiamondDeck® is used in conjunction with a CertainTeed roofing product, DiamondDeck will take on the same warranty period as the shingle above it. When DiamondDeck is used with a non-CertainTeed product, the limited warranty period will be 30 years.

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