Key Features

  • Specialist non-combustible fiber cement board technology for the construction of rated floor assemblies and fire rated ceiling assemblies; a lightweight alternative to poured concrete.
  • Non-combustible per ASTM E136; up to 2 hour fire-rated floor assemblies.
  • International Building Code Approval (IBC).
  • International Residential Code Approval (IRC).
  • Excellent load bearing performance, with UL listed floor assemblies; structural loading bearing sheathing over supports out to 24” on centers.
  • Excellent acoustic insulation, with STC and IIC rated assemblies.
  • Cuts and installs using standard carpentry tools and equipment.
  • Compatible with most traditional floor finishes.
  • Moisture resistant, insect / vermin proof, and impact resistant.
  • Environmentally safe and manufactured with recycled materials


Plycem SX20/20 (formerly Plycem Cemdeck) is specified and listed under CSI Division 3-03500 Cementitious Decks and Underlayment.



  • UL & ULC classified for use in fire-rated construction (UL 723, Test for Surface Burning Characteristics of Building Materials; UL 790, Test Methods for Fire Tests of Roof Coverings; and UL 263, Fire Tests of Building Construction and Materials).
  • UL & ULC tested against ASTM E84 and E136
  • Zero flame spread and zero smoke development per ASTM E84.
  • Non-combustible per ASTM E136; 1 and 2 hour fire-rated floor assemblies.

Load bearing:

  • Structurally span rated, with UL listed floor assemblies

Acoustic insulation:

  • STC rated assemblies per ASTM E413
  • IIM rated assemblies per ASTM E989

Moisture resistance:

  • Factory sealed against water penetration.


  • Minimal dimensional changes in temperature & moisture variations


  • No food value to insects / vermin


  • 71% Portland cement
  • 19% mineralized cellulose fibers (derived from recycled cardboard cartons)
  • 9% water
  • 1% bonding agents.


  • Available in 4’ x 8’ sheets
  • Thicknesses 3/4” and 1”.

Product Brochure & Submittal Sheets

Specification & Certification

Building Code approvals

The Plycem 25mm Structural Flooring described has been evaluated for use as floor sheathing to support gravity loads for interior residential use. The Structural Flooring is permitted under the IBC on Type V Construction and buildings constructed in accordance with the IRC. The Structural Flooring has been evaluated for strength, physical properties, surface burning characteristics and non-combustibility.

The Plycem 25 mm Structural Flooring evaluated is as a satisfactory alternative to the following codes and regulations:


  • 2015, 2012 and 2009 International Building Code® (IBC)
  • 2015, 2012 and 2009 International Residential Code® (IRC)

Combustion Characteristics

Physical / Mechanical Properties

Acoustic Performance (STC & IIM):

Fire-Rated Floor/Ceiling Assemblies (ASTM E-119)

The following examples are indicative of the fire-rated floor/ceiling assemblies which are available. Please contact us for more information.

NYC Dept of Buildings, Materials & Equipment, Acceptance Division:

Installation Guides


  • USAP recommends 8 diameter minimum x applicable length, corrosion resistant screws with self-countersinking heads and self-drilling ‘Tek’ points. The length of the fastener should be a minimum of 2x the board thickness.
  • For attaching 20mm (3/4″) Plycem Cem-Deck boards to steel framing (20 – 12 gauge)
    1. Grabber Part No. HS8158JBWG2 (#8 x 1-5/8″)
    2. Hilti PWH SD Cement Board Screw, No. 00372760 (#8 x 1-5/8″)
    3. ITW Buildex S-12 ‘Rock On’ No. 2159500 (#8 x 1-5/8″)
    4. Pro Twist Cement Board Fasteners
  • Screw Fastener Pull-Out Test Report


Compounds, Sealers & Stains

Plycem SX20/20 Projects

Alexan Uptown, Denver

This 12 story tall apartment building is the first high-rise building undertaken by construction technology specialist Prescient, and their tallest structure to date.

Read More…

View Project

Capitol District 02

Capitol District Apartments, Omaha

Plycem SX20/20™ was selected for the construction of the 218 unit Capitol District Apartment building.

Read More…

View Project

Hyatt House, Belmar

Hyatt Hotel Belmar, Lakewood, CO

Plycem SX20/20™ was selected by Prescient as the subfloor material for Hyatt House Belmar – the first project in the hospitality sector to use Prescient’s innovative design, engineering and construction platform.

Read More…

View Project

University Station, Denver

University Station, Denver

University Station is a six-story development providing one and two-bedroom apartments for affordable senior living in South Denver.

Read More…

View Project


Avalon Willow Condominiums, New York

Avalon Willow Condominiums in Mamoroneck, New York features more than 230,000 sq. ft. of 1” PlyCem CemDeck in its construction.

Read More…

View Project

Foxwood Casino Resort

Foxwoods Casino, CT

PlyCem SX20/20™ was used for more than 50,000 sq. ft. of decking at Foxwoods Resort Casino in Mashantucket, one of the largest casinos in the world.

Read More…

View Project