digest
Short Summary
Main recommendation: For a low-cost waterproof shower that lasts about 20 years, use mold-resistant drywall, seal the corners and joints with Laticrete 2-in-1 sealing bond, then apply RedGard roll-on membrane in at least three thick coats. The speaker says this costs no more than the tile itself and is more durable than the water-resistant drywall now allowed by local code.
Key Points
- The speaker argues that code allowing ordinary drywall with adhesive-set tile, or only water-resistant drywall, leads to many showers failing in 5 to 10 years, even in new homes, though this is based on his own experience/opinion and regional code.
- Mold-resistant drywall with a mold inhibitor is presented as a base layer that should delay mold growth through the wall by another 20 to 30 years if the waterproofing fails.
- Laticrete 2-in-1 sealing bond is used in the corners and joints instead of drywall compound, which the speaker says causes problems; it is described as interior-use with low off-gassing.
- RedGard is described as a thick, paint-like roll-on membrane available at local building stores, and the speaker notes its fine-print cautions are often unread on the label.
- Coverage density matters more than coverage area; the speaker says a membrane must be built thick, not applied in a single pass.
Details Worth Noting
- Concrete instructions:
- Install mold-resistant drywall with the joints as tight as possible.
- Wipe out any leaks or holes before proceeding.
- Run a healthy bead of Laticrete 2-in-1 sealing bond into each interior corner, then press it down with a finger. It sets up quickly, about 15 minutes.
- Brush RedGard into the corners, the drywall joints, and the bottom edges of the wall first, painting the sides and "picture-framing" the area with the brush.
- Use a mini roller rather than a large-nap roller, since the product is thick and a large roller would hold too much. Mini roller refills cost only a few dollars and can be discarded.
- Apply RedGard in at least three coats for a durable seal, waiting until each coat is tacky before the next.
- Check thickness by painting over the screw holes: when a screw hole becomes a solid pink dot after a pass, the wall has enough material.
- Each coat is the same product; the speaker says the seal is much better at three coats than at two.
- The speaker says the membrane is applied mainly from the shower floor area up to the top of the shower, though applying it to the full wall is also acceptable.
- Product cost is about $50 for RedGard, according to the speaker.
- The speaker says the method has been used for over 40 years and claims a shower built this way should last about 20 years.
- The speaker notes that conditions such as temperature and humidity change results, so the viewer should judge when two, three, or four coats are enough, aiming for a nice thick coat.
- Health and building-code claims are the speaker's own; this is not professional advice.
Bottom Line
A layered approach of mold-resistant drywall, sealed corners, and three thick RedGard coats is presented as a low-cost alternative to expensive waterproofing systems that still aims for a long service life.
