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Q: What is 90 compound and where is it used?

A: There are two different types of joint compounds; drying and setting types. Drying type compounds are composed of limestone and binder. These compounds must dry out completely before the binder becomes effective. Setting compounds work well with fiberglass mesh tape. ToughRock® 90, the Georgia-Pacific Gypsum brand of setting compound, is recommended for skim coating DensShield® Tile Backer and DensGlass® Sheathing (see literature for application recommendations).

Q: What are the similarities and differences in DensArmor Plus® high-performance interior panels and DensShield® tile backer?

A: DensShield® tile backer and DensArmor Plus® high-performance interior panels similarities: Both use coated fiberglass mats as the back facer material. When installed against the wall framing, both products provide a fiberglass mat surface facing the wall cavity that resists possible mold growth on the back of the panel. DensShield and DensArmor Plus both have cores that are moisture resistant, manufactured to ASTM C 630 specifications. DensShield and DensArmor Plus differences: DensArmor Plus does not have a water-stopping acrylic coating. The coating on DensShield provides a water barrier to stop moisture from penetrating into the product and wall. DensShield is made to be used in wet areas such as showers and tub areas as a substrate for ceramic tile. DensShield is manufactured to ASTM C 1178. DensArmor Plus features a tapered edge for joint finishing while DensShield has a square edge.

Q: What are the wicking characteristics of DensArmor Plus® panels?

A: With its moisture-resistant core and the absence of paper facings, DensArmor Plus® drywall resists wicking similar to DensShield® Tile Backer. (.31" over 24 hr. period)

Q: Can a contractor use DensArmor Plus® in a pool area, or a pump house and other areas of extreme moisture?

A: DensArmor Plus® is a suitable panel to replace green board. It should not be specified in areas that will see moisture levels higher than that of a residential bathroom. For pool areas, see DensShield® Tile Backer.

Q: Can you use DensShield for non-tile finish systems?

A: Please refer to our technical brochure for using DensShield in indoor swimming pools, gang showers, car washes, food processing units, laboratories, other consistently humid areas and under surfaces that will be washed on a regular basis. Refer to the complete technical guide (PDF: 1.3MB/12pgs) for information.

Q: What is 90 compound and where is it used?

A: There are two different types of joint compounds: drying and setting types. Drying type compounds are composed of limestone and binder. These compounds work best with paper tape and must dry out completely before the binder becomes effective.  Setting compounds set hard prior to drying, much like concrete and are more resistant to moisture than drying type compounds.  Setting compounds work well with fiberglass mesh tape. ToughRock™ 90, the Georgia-Pacific Gypsum brand of setting compound, is recommended for skim coating DensShield® tile backer.  Click here for installation instructions (PDF: 670KB/12pgs).

Q: Why should I apply thin-set mortar to the subfloor before putting down DensShield® tile backer?

A: Many of our customers feel as long as they are using mechanical fasteners such as nails or screws to fasten DensShield tile backer to a sub-floor, that applying thin-set mortar is a superfluous step. This is not true. The application of thin-set over plywood eliminates any air gaps between the subfloor and the back of the DensShield panels. If this step is not completed, air gaps could cause movement and crack the grout lines or tile.

Q: How do I finish DensShield® tile backer joints?

A: Apply standard 2" 10 x 10 woven glass mesh tape over joints and angles. This is the same type of tape used for taping cement board joints.  Then, embed the tape with the same material  used to set the tiles.  Do not use all-purpose drywall compound.  Pull setting materials tightly over the joints to reduce crown in the joint area.

Q: How does DensShield® tile backer compare with cement board?

A: DensShield Tile Backer has a built-in moisture barrier and therefore does not require a secondary moisture barrier. Cement board does not have a built-in moisture barrier and may require a secondary moisture barrier.  In addition, DensShield has a considerable weight advantage over cement backers.  It's 30% lighter than the leading cement board brands (1/2" comparison). That makes DensShield easier to handle on the job site and faster to install.  A study conducted by the National Association of Home Builders (NAHB) Research Institute showed that DensShield is 46 percent faster to install than cement board.

Q: Can I paint DensShield® tile backer outside the shower area in a typical residential bathroom wall installation?

A: Yes, the steps to accomplish this are quite simple. First, finish the joints using fiberglass mesh tape and setting type joint compound. Next, skim the entire DensShield panel surface with setting compound. Once this material dries out, prime and paint, or prime and paper. The use of setting type joint compounds are preferred over ready mix joint compounds near moist areas.

Q: Can I use DensShield® tile backer on the exterior of a building as a tile backer or as a base for EIFS?

A: No, DensShield is not for exterior use.

Q: If the grey coating on DensShield® tile backer is torn, can I fix it, or do I need to replace the board?

A: There are two ways to accomplish this repair. The first method is the best one. The second method is recommended for residential applications only. Depending on the size and extent of the damage, the second method may not be effective.

Method 1: Remove affected tile area and surrounding tiles from stud to stud. This includes removing the DensShield panels.  Fasten additional studs, known as "scabs," to the sides of the original studs to support the new DensShield. Install DensShield panels. Caulk the edges of the new DensShield with a silicone sealant caulk so the joint is waterproof. After caulk has cured, install new tiles and grout.

Method 2: Remove grout from around the affected area. Carefully score through the acrylic finish of DensShield panels under the affected area. Remove the tile, including the gray acrylic DensShield finish. Do not remove the DenShield panels.  Use a penetrating sealer/primer such as shellac primer or solvent-based primer to seal the exposed DensShield core. Install the tile with either a mastic or modified thin-set. Regrout the area.

Q: To which side of DensShield tile backer should I apply tiles?

A: The DensShield panel should be positioned next to framing with the coated (grey) side facing away from the studs.  Apply mortar or mastic and tile to the coated (grey) side of DensShield.  The acrylic coating stops moisture penetration on the surface.

Q: What makes DensShield® tile backer different from greenboard (paper-faced moisture-resistant gypsum board)?

A: DensShield Tile Backer is an entirely different product than greenboard.  The paper facings of greenboard can wick water, and can delaminate when exposed to moisture, causing tile failure. Greenboard is not recommended for use in extreme high moisture (wet) areas  and therefore does not meet the 2006 IRC Section R702.4.2 for backer for wall tile in tub and shower areas.  DensShield Tile Backer has a heat-cured acrylic coating over its face mat with face and back mats made of fiberglass instead of paper, and has a proprietary, treated moisture-resistant core.  DensShield offers a proven tile backer design that is compliant with more stringent 2006 IRC and IBC codes.

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