Premixed thinset mortar does not adhere well to RedGard waterproofing membrane. In order to make sure your tile bonds well to a surface that has been waterproofed with RedGard, use a powdered mortar. You will need to mix this mortar with water yourself, but it will ensure a strong bond between the tile and the wall.
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What Happens if You Use Premixed Thinset Mortar Over RedGard?
Because premixed thinset bonds poorly with RedGard, tiles installed using premixed mortar will pop off or fall. This may happen shortly after you complete tile installation, or it may take a few months, but your tile installation will not hold up if you use premixed mortar over Redgard.
- Tiles installed on RedGard with premixed mortar will pop out or fall off after installation.
- Deterioration of your tilework may occur shortly after installation or after several months.
- In addition to RedGard, premixed mortars form a poor adhesive bond with similar waterproof membrane products.
This rule extends beyond RedGard products. Other products that provide waterproofing for showers do not bond well with premixed mortar. Opt for higher-quality powdered mortar no matter what non-permeable membrane you’re using in your shower.
What Kind of Thinset Should You Use Over RedGard?
Use a high-quality powdered thinset mortar to tile your entire shower walls. Anywhere you have painted RedGard, use powdered thinset. Using the proper thinset mortar will ensure your tiles remain in place and your tilework remains durable for years to come.
- Use this powdered mortar when installing tile on surfaces painted with RedGard.
- Add cool water to powdered mortar, mixing as you go.
- When the powdered mortar has a peanut butter or cake batter consistency, it’s ready for use.
To prepare your powdered thinset for use, pour 5 pounds of mortar powder into a large bucket. Then, slowly add cool water to the powder. Mix this with your mortar trowel. Once the mortar has the same consistency as peanut butter, it’s ready for use.
Do You Need to Use RedGard Over Cement Board?
To truly waterproof your wall, you should apply RedGard or a similar waterproof vapor barrier over cement board. Although a typical cement board is far more water-resistant than drywall, showers are exposed to large amounts of water. This water can seep through tile, grout, and cement board to cause mold, mildew, and wall damage.
- It is essential to waterproof cement board with RedGard or a similar product.
- Water from your shower can penetrate tile installations and concrete board if the shower is not properly waterproofed.
- Apply Redgard to every surface where shower tile will be installed.
Don’t skimp on waterproofing your shower. Because showers have so much water on-site, they are the number one cause of mold and mildew in homes. Roll RedGard or another waterproofer onto your concrete board surfaces. Once it’s dry, you’re ready to install your wall tiles.
Can You Tile Directly Onto RedGard?
There’s no need to put another layer of product on top of RedGard before you begin tiling. A surface that has been painted with RedGard and allowed to dry is ready for you to apply thinset and install tile.
- You can install thinset mortar and tile directly onto RedGard.
- For best results, mix mortar in small batches and apply it to the shower wall a small area at a time.
- Use a notched tile trowel to spread mortar whenever you are tiling over RedGard.
When tiling over RedGard, it pays to mix your mortar in small batches. Then, apply the mortar to your wall in two-foot-square sections as you tile. This will make certain your mortar does not set before you can install tile on top of it.
Will Mortar Stick to RedGard?
Powdered, unmodified thinset mortar will stick to RedGard waterproofing membrane and securely fuse your tile in place. To make sure your tile installation goes well and remains durable, follow these rules:
- Allow RedGard to fully dry before you begin tiling.
- DO NOT use a premixed thinset mortar—it will not stick to RedGard
- Use a powdered thinset mortar you mix yourself.
- Mix your powdered mortar with cool water until it reaches peanut butter consistency.
- Tile in small sections so your mortar is always fresh.
This simple system will yield incredible results. Your tiles will remain in place, your shower will be waterproofed, and you’ll be able to enjoy your handiwork without worry.