Waterproofing

This is concerning and needs to be addressed before proceeding further. Here's what you need to know: RedGard Application Standards: RedGard (by Custom Building Products) requires TWO coats as per manufacturer specifications. The first coat should be a consistent pink color, and the second coat (applied after the first dries) should be applied perpendicular to the first. When properly applied, you'll see a uniform, solid red color indicating full coverage. Your Specific Concerns: One coat is NOT enough - The manufacturer requires two coats for proper waterproofing protection. One coat leaves you vulnerable to water penetration. Uneven/incomplete coverage is a serious problem - Waterproofing is only as good as its weakest point. Any thin spots, gaps, or missed areas create pathways for water to reach the substrate, which can lead to: Mold growth behind tiles Tile delamination Structural damage to drywall/framing Failed grout joints Basement Context: In a basement, proper waterproofing is even more critical because: You're below grade with potential hydrostatic pressure Moisture problems are harder to detect until significant damage occurs Repair costs are exponentially higher than doing it right initially What You Should Do: Stop work immediately if tiling hasn't started Request proper application: Two full coats of RedGard with complete, even coverage Verify the contractor is following manufacturer specs - they're required for warranty coverage Consider having this inspected before proceeding Your contractor saying "no" to a membrane isn't necessarily wrong (RedGard IS a liquid-applied membrane), but cutting corners on proper application absolutely is wrong. This is not an area to compromise on.

Typically RedGuard reqires at least Two coats of application.

Attest tow coats of Redgard are required on bathroom walls to properly cover but membrane is better option.