Don’t use tile mastic in wet areas like showers, over cement board, fiber cement board, Kerdi, floors, or with glass tile, large format porcelain tile, natural stone, or most anywhere else. If you want to use a backer board with a built in moisture barrier than you should use DensShield by Georgia-Pacific. And … Then, the cement board is installed on top of The waterproof membrane isn't … You could go with kerdi over cement board, you will need an expert to tell you if this is better then kerdi over drywall, though i will guess its unnecessary. Rock-On #9 x 1-1/4 in. Hi, I am re-doing my shower. GBA Editor Martin Holladay | Jul 26, 2015 06:53am | #3 Yasir, Kerdi-Board . The best way to get rid of the glue is to grind it off with an electric grinder and a diamond cup wheel. It's all about the If there are any cracks in the floor, you need to use some sort of a membrane. Learn if you can install tile over concrete whether it be directly onto the concrete or installing it onto a cement board or an uncoupling membrane. How to Waterproof Cement Board around a bathtub. Finally, it must be well adhered, if not you need to start over. Not every wall does. After the insulation is in place you will want to add a vapor retarder, sometimes called a vapor barrier, if you need one. Even if you use a waterproof underlayment membrane, the floor will still be either 1/4″ or 1/2” higher Do we need to apply RedGard over it or would it be an overkill? Serrated Flat Head Star Drive Cement Board Screws (185-Pack) $7.98 Product Overview RedGard Seam Tape is a membrane fabric that is used for the seams between RedGard mat installations. The contractor will have to buy a 1 gallon bucket and follow the directions for your particular situation. I think this product is expensive, But even though the tile experts that taught me methods of redoing a bath surround, say that you do not need to waterproof the cement board they could not be more mistaken. Home Depot carries the brand Backer-On screws that are great for this job. Definitely use cement board instead of green board. You will also use it to attach the tile to the backer board. We rolled the RedGard on the cement You need to make sure that the entire gap between the boards is filled up with the thinset. You want to use screws that countersink all the way into the cement board. Do not use WonderBoard® Lite as a structural load bearing member. Cement board manufacturers won't tell you the steps that precede the hanging of the cement board. Yes, you can redgard over the seam at the floor, and yes, you should install redgard over all the cement board if you don’t have a barrier behind it. It won’t hurt to use RedGard on all the cement board. Cover the tub with plywood and tap a flat bar behind it - you may be How to Install Wall Tile Over Backer Board. I have the HardiBacker board up and the seams are taped and mudded with alkali resistant mesh tape and thin-set. Now days in my own home I do use Redguard even though just cement board will outlast me. Either you use a vapor barrier behind the hardi, or you can use a waterproofing system (like redgard) over the hardi, but you should not do both. The only place it’s OK to use it is when tiling in non-wet areas, over drywall, with small ceramic tile. :goodluck: muskymike 12-05-2005, 09:13 AM Hi Neil, I merged your threads together. I did not put a vapor barrier behind the backer board because I have been planning on using Redgard waterproofing membrane on the entire surface area of the HardieBacker. Nor will they tell you how to tile over it, or what color grout to use. You can choose which samples are free in the checkout. Applying RedGard will block out moisture and yes, you would then need to use a polymer modified thinset. But the application is pretty easy. I also read that DensShield backerboard has a waterproof layer over gypsum core. We chose DensShield for its better environmental attributes. I have actually heard of people using tarpaper for this, but I chose to use RedGard. Use a drill fitted with a mixing paddle to mix the thinset. Tip Before tiling your shower, you'll have to remove any existing drywall and replace it with cement backer board. The cement board should be plumb, hence the need for shims sometimes. While it might sound like a good idea to install cement backer board over drywall before tiling the shower, the reality is that the drywall should be removed beforehand in most instances. No, you’ll need to tape and mud it, then use redgard over that. However, I have been hearing that Redgard does not work well with HardieBacker … Mix the thinset as if you’re mixing batter. Take a trowel or a taping knife and use it to apply the thinset to the gap. You could use a foam board like Wedi or a leveling compound. While I prefer using 1/2” cement backer board over a plywood subfloor, you may be able to get by with 1/4” backer board instead. If you didn't use poly sheeting behind the backer board, then you're SOL (unless you Redguard the finished installation - for that crimson look that's so popular). Always add the dry thinset mix to the water — not the other way around. From what I read in the posts on backerboards in GBA I see several comments on how well RedGard membrane is performing for the shower and tub areas. The RedGard was supposed to be compatible with cement board, but the manufacturers instructions did not specifically mention HardiBacker, so I called both Custom Building Products and Hardie, and they both said 'should be Please consider joining my Patreon network. You absolutely need to include some sort of substrate (cement board, green board, regular drywall) with the Schluter-Kerdi waterproofing kit. A . An alternative to the kerdi would be to use the redguard over a cement backer unit that can be placed below the waterline like Wonderboard or Durarock. Unless you meant ‘can I tape the gap and use redgard over it’, in which case the answer is yes. Step 3 Pre-coat corners heavily and lay fiberglass mesh tape that is 6 inches wide into the wet RedGard to reinforce the transition. All other samples will be full size and paid for. Cement Board and Plastic Sheeting In this highly convenient, inexpensive, and popular application, a moisture barrier of 4- or 6-mil-thick plastic is installed directly over the wall studs. I got two gallons at Home Depot yesterday. If it’s too large to fill with caulk it’s too large to fill with redgard. Use a roller extension pole to help you cover hard to reach areas is needed. 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