What is Cem-Rock®?
Cem-Rock® is a family of magnesium oxide cement boards designed to replace plywood, OSB, fiber cement board and interior and exterior gypsum based sheet building products.
What is Cem-Rock® made of?
Cem-Rock® is made of Magnesium Oxide (MgO).
What is Magnesium Oxide?
Magnesium Oxide (MgO) is a naturally occurring inorganic mineral that is mined from the earth much
like Portland cement.
Can Cem-Rock® be used externally?
Yes, Cem-Rock® can be used internally or externally.
Where is Cem-Rock® most commonly used?
Cem-Rock® is most commonly used as exterior sheathing, interior wallboard, subflooring, ceilings,
roof decking, fire-resistant wall and subfloor assemblies and tile backerboard.
What sizes is Cem-Rock® available in?
Cem-Rock® is available in 1200, 2400, 2700 and 3050mm lengths and 1200mm wide sheets. Other sizes are available by special order.
What thickness is Cem-Rock® available in?
Cem-Rock® and Cem-Rock® eXtreme are available in 6, 10, 12 and 15mm. Cem-Rock® FLOOR is available in 18 and 20mm. Other thicknesses are available by special order.
How do you install Cem-Rock®?
Cem-Rock® is installed in a similar fashion to gypsum board, plywood, or OSB.
Can you nail Cem-Rock®?
Cem-Rock® can be nailed or screwed.
Does Cem-Rock® feed mould?
Cem-Rock® is completely inorganic, does not rot, mold or feed mildew and has a 0/0/0 mold rating.
Is Cem-Rock® flammable?
No, Cem-Rock® is non-combustible and is Class A1 fire rated, with a 0 flame spread and 0 smoke
developed rating. No other plywood, OSB or gypsum based product can claim this.
Is Cem-Rock® heavy?
No. A sheet of Cem-Rock® weights approx. 30kg and Cem-Rock® eXtreme weights approx. 37kg
Is Cem-Rock® people safe?
Yes. Cem-Rock® is completely non-toxic. It is manufactured from 100% natural inputs
and does not off-gas. It is exceptionally good for Asthma or chemically sensitive people.
How do you cut Cem-Rock®?
Cem-Rock® can be scored and snapped like gypsum board, or you can use a circular saw.
Is Cem-Rock® contractor friendly?
Yes, Cem-Rock® can be cut with a utility knife using score and snap method and also, dust generated when cut with a circular saw is non-carcinogenic. Cem-Rock® does not contain known toxins such as formaldehyde, crystalline silica or fly ash.
Is Cem-Rock® an approved building material?
Yes, Cem-Rock® carries all required certification.
What happens when Cem-Rock® gets wet?
Nothing. It dries out and is unaffected by exposure to water.
Is Cem-Rock® waterproof?
Cem-Rock® is impervious to water, both fresh and salt. Being cementitious, it does
however absorb some water.
Is Cem-Rock® termite proof?
Yes, Cem-Rock® is completely resistant to all wood boring insects.
Is Cem-Rock® dimensionally stable when wet?
Yes. Cem-Rock® is one of the most dimensionally stable sheet building materials on the
When should Cem-Rock® be used?
Cem-Rock® should be used wherever there is a need for a fireproof, mold proof, insect proof, waterproof and high impact alternative to gypsum board, plywood, OSB or fiber cement board.
What kind of screws do I need to fasten Cem-Rock®?
Stainless steel, yellow zinc coated or rust proof coated screws for fastening into steel framing or wood framing are recommended.
Traditional (black) gypsum screws are not recommended.
Is pre-drilling necessary?
No, pre-drilling is not necessary.
Do I need blocking to hang objects when using Cem-Rock®?
When using Cem-Rock® eXtreme, you can hang practically anything with no additional blocking needed.
(See Product Data Sheet for maximum fastener capacities). When using Cem-Rock®, blocking or plasterboard dowels might be required, depending on what is being fixed.