Cement Board

PermaBASE UltraBacker® Cement Board

Provides an exceptionally hard, durable surface and can withstand prolonged exposure to moisture.





Rigid substrate providing superior tile bond

Smooth glass mesh and mat surface provides added rigidity for improved handling
  • A cement backer board is perfect for use in interior applications such as kitchen counters and as an underlayment for ceramic tiles.
  • Highly moisture-resistant, will not rot, disintegrate or swell when exposed to water.
  • The 1/4-in thickness eliminates the need to modify adjacent thresholds when abutting to carpet, wood floors.

PermaBASE UltraBacker® Cement Board features a smooth mesh and mat surface that creates a more rigid and easier to handle product and an improved surface providing superior tile bond. It is ideally suited as an underlayment for ceramic tile on floors, countertops, tub decks, and outdoor kitchen counters.


  • Features lowest water-absorption rating of <8% (ASTM C473).
  • Stays intact when exposed to water; will not rot, disintegrate or swell.
  • Helps inhibit mold growth with the highest possible score on mold tests (ASTM D3273 and ASTM G21).
  • Resists impact and remains dimensionally stable.
  • Holds up to toughest conditions.
  • Can be applied over new or existing countertops or as flooring underlayment.
  • Pre-manufactured panels save you time.

Interior Applications

Video: PermaBASE UltraBacker® Cement Board


Video: Flooring Installation with PermaBASE UltraBacker Cement Board



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Related Resources

Product details and technical documentation

Code Reports

Drop-In Specs

UL GREENGUARD Certification

Frequently Asked Questions

Ready to answer your product and installation questions

What kind of fasteners do I use to install PermaBASE UltraBacker® Cement Board?

Corrosion resistant screw or galvanized roofing nails. Strongly suggest PermaBASE screws since they do not have nibs like competitor screws.

What do I tape the PermaBASE UltraBacker® cement board joints with?

2” Alkali resistant mesh tape and mortar mix.

What is the required joist spacing for floors?

For flooring applications with 16" o.c. floor joists, 5/8" tongue-and-groove exterior-grade plywood or 3/4" tongue-and -groove exterior-grade OSB may be used. For 19.2" o.c. and 24" o.c. floor joists, 3/4" tongue-and-groove exterior-grade plywood or OSB must be used. Tile size for floors with 24" o.c. floor joists must be 12" x 12" or larger. The joist and subfloor assembly must meet L/360 as well as the appropriate code tables for live and dead loads.

What is the fastener spacing for floor applications?

Every 8” o.c. along the perimeter and field of board.

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National Gypsum Company is the exclusive service provider for products manufactured by PermaBASE Building Products, LLC.