One of the most important questions you may have about laying tile over hardibacker is do I need to use Redgard over it? The answer depends on your project. While Redgard has a good bond with hardi, it is not waterproof. You should apply one or two coats of thinset over the redgard. If you want to tile directly over the hardi, wet the tile set with a spray bottle or sponge.

Redgard is a waterproof vapor barrier

One of the main differences between the two waterproofing systems is the type of membrane used. RedGard is a water-resistant membrane that can be applied behind or over the hardibacker. While hardi itself is not waterproof, it will not be harmed by water or moisture. However, RedGard is waterproof and does not need a vapor barrier. RedGard is applied with a roller and can be rolled on any surface.

Redgard is considered a waterproof membrane by manufacturers. The company says that it is an effective surface waterproofing membrane. It should prevent water from permeating through the subtrate and into the wall cavity. However, this is difficult to explain in plain English. Regardless, the company behind Redgard claims that it is a waterproof vapor barrier, but the question is – does it really perform as promised?

It will never leak

The main claim behind the product, “Redgard will never leak,” is not entirely true. Although the product is rated waterproof, water will seep in both directions through its porous cement board. If water seeps into the wall from behind the shower, it will get into the walls. So, it’s best to combine Redgard with a waterproofing sealant for tile and grout. This will be equivalent to double waterproofing.

Another advantage of Redgard is that it won’t require a professional to install it. You can apply it yourself, with a 3/4-inch nap roller or a sprayer. This means you won’t have to hire a drywall installer to install the product. If you are planning to cover the drywall with tile, you can apply Redgard yourself, too. Unlike some other waterproofing materials, Redgard won’t leech into the drywall.

It will block moisture

If you’re building a shower stall, you may be wondering whether or not you should use RedGard. The “Moisture Sandwich” myth is a common misconception, but this product actually does work to block moisture. It does not stick to 100% silicone caulk, which can be problematic if the shower stall is not properly waterproofed. It does however block moisture, and you won’t need to worry about leaks in the future.

RedGard is a liquid formula for exterior and interior substrates. It forms a seamless, waterproof barrier, preventing the common cracks in grout, tile, and stone. Because it is water resistant, it can be applied over thinset, concrete, and cement backerboard. This product also bonds to metal drain assemblies. It can also be used over plywood subfloors. The red-colored substance is very effective against water and prevents mold from forming.

It will adhere to thin-set mortar

The waterproofing membrane on RedGard must be applied over a concrete substrate, and the tile must be installed over the thin-set mortar. If the tile is not properly bonded to the concrete surface, it may pop off or fall off. It is important to use a modified thin-set mortar when installing tiles on a Redgard surface, as unmodified thin-set mortar does not adhere to waterproofing membrane.

Applying RedGard to the surface with thin-set mortar can be a tricky task. The material does not bond well to thin-set mortar unless the surface is porous. It is best to apply the thin-set mortar over the surface in small sections, one two-foot square at a time. Apply the thin-set mortar with a notch tile trowel to the surface and tile carefully. The thick layer should not be too thick or too thin, as this could lead to a cracked tile.

It will not disintegrate or lose strength when wet

Before you apply the RedGard membrane, you should let it cure for one to one and a half hours. When fully dry, the RedGard material will be a solid red color. The time required for the material to cure will vary depending on the ambient conditions. It is not waterproof, so it is important to allow it to dry completely before use. Once dry, it is not necessary to apply a second coat.

When applying RedGard, cracks of up to 3 mm in size should be prefilled with a 3/4″ rough-textured synthetic roller or a 3/16″-1/2″ (56 mm) V-notch trowel. Then, use a fiberglass mesh to embed into the waterproof membrane. Once the fills are dry, apply RedGard, which will prevent water from penetrating both sides of the surface.