DUROCK® Cement Board

No.

Yes. DUROCK Brand Cement Board has a minimum-bending radius of 8 feet.

No. This span may result in panel deflection beyond L/360.

No. Effective screw attachment is compromised on thinner gauge steel resulting in loose panels that may cause tile cracking.

No. DUROCK Brand Cement Board is typically used in wet areas, both interior and exterior, and joint compound is a water-soluble product that will deteriorate if exposed to water or moisture.

No. Where shear ratings are required, place plywood or diagonal bracing behind the DUROCK Brand Cement Board. This is the best way to achieve the shear value that is required.

Yes. Using DUROCK Brand Cement Board allows the clearance between the UL rated heating appliance and the combustible wall to be reduced to as little as 12 inches.

Yes, but only small areas. DUROCK Brand Cement Boardis designed to micro-crack. Conventional paint is too thin and not elastic enough to span these very small cracks. The recommendation for painting DUROCK in small areas that are not tiled is to seal the board with a mixture of ceramic tile adhesive and water in a 4:1 ration. Then treat joints and smooth surface with a setting-type joint compound and paint. As an alternate, apply a latex modified cement basecoat over the DUROCK Brand Cement Board and finish with an exterior grade acrylic coating.

DUROCK® cement board should be stored in its original unopened packaging in an enclosed shelter that provides protection from damage and exposure to the elements. Even though the stability and durability of DUROCK cement board is unaffected by the elements, moisture and temperature variations may have an effect on the bonding effectiveness of basecoats and adhesives.

No. DUROCK is not a structural product. It cannot support live or dead loads without a structural sub-floor like plywood underneath.

It depends on the finish application. DUROCK has a smooth side that is designed for tile set with tile mastic (Type 1 organic adhesive) and a rough side for tile set with a latex portland cement thin set mortar.

Yes. However DUROCK Brand Cement Board in a finished application can store the small amount of water that gets past the tile, grout and the setting bed. In applications where the DUROCK System may be exposed to large amounts of water like on exteriors or in gang showers, USG recommends the use of a water barrier behind the board and flashing at the bottom of the wall to allow any intruding moisture a place to escape. Water does not harm the DUROCK Brand Cement Board.

DUROCK® Cement Board can withstand temperatures of up to 175 degrees F.

DUROCK® Cement Board has a flame spread of 5, and smoke development rating of O.

DUROCK® Cement Board has an R value of 0.26 and a K value of 1.92.

Yes. DUROCK® Cement Board has a minimum-bending radius of 8 ft.

DUROCK® Cement Board can withstand 100 freeze/thaw cycles.

Yes. However DUROCK® Cement Board in a finished application can store the small amount of water that gets past the tile, grout and the setting bed. In applications where the DUROCK® System may be exposed to large amounts of water like on exteriors or in gang showers, USG recommends the use of a water barrier behind the board and flashing at the bottom of the wall to allow any intruding moisture a place to escape. Water does not harm the DUROCK Cement Board.

DUROCK® has a warranty for 30 years from the date of installation for interior application and a warranty of 10 years for exterior application. See complete warranty for details.

The main concern is freezing and thawing in cold climates which will deteriorate the DUROCK panels. DUROCK panels could be used below grade in a warm climate provide the DUROCK panels are not being used to provide water proof construction. DUROCK panels are designed to allow moisture to go through the panels. Above grade the small amount of moisture that may get into the DUROCK panels can escape to the outside air. Below grade this moisture may go through the DUROCK panels and into the framing or cavity without any means to escape. This moisture may be detrimental to the framing, the stud cavity or interior surfaces.

Most exterior finish systems are L/240, however when using thin brick or tile finishes, the maximum is L/360.