Cem-Rock® Extreme Floor boards represents a quantum shift in flooring technology and has been developed to rapidly improve on flooring technology. Its fire, water, mold and mildew resistance properties far outweigh any competing products like plywood or OSB floor sheathing. Cem-Rock® Extreme Floor boards provides a superior flooring solution that is unaffected by environmental exposure during construction.

Cem-Rock® Extreme Floor boards reduces the risk of fire, is not affected by adverse weather conditions, and drastically improves your building’s structural performance. Cem-Rock® Extreme Floor are Non-Metal Corrosive, MgO Boards tested for Non Chloride Non Corrosive Content. Cem-Rock® Extreme Floor boards provide second to none MgO Tongue and Groove flooring that are made with high quality composites that are also environmentally friendly and sustainable.

Product Options

Extreme Floor – Square (4’ x 8’ x 3/4″)

Extreme Floor – Tongue and Groove (4’ x 8’ x 3/4″)

Extreme Floor – Ship Lap (4’ x 8’ x 3/4″)

Suspended Floors
External Decking
Floor Underlay

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A1 Fire resistant

Water proof

Sound Absorption

Reduced floor deflection

Technical Specifications

Prodcut Name/ Category:

Cem-Rock Extreme MgO Structural SubFlooring Board

3/4” T&G Load-bearing SubFlooring Board


4’ x 8’


3/4” (19mm)


Tounge & Groove (T&G)

Per Sheet Weight:

131 lbs

Pallet Quantity:

22 Sheets

Fire Performance:

ASTM E84: Zero Flame, Zero Smoke

ASTM E136: Passed

Environment Certifications:

UL Green Guard

UL Green Guard Gold