USG™ Durock® Liquid Waterproofing & Crack Isolation Membrane is a liquid-applied, acrylic polymer–based elastomeric membrane designed for waterproofing, crack isolation, and vapor control in tile and stone installations. It is approved for use over a range of substrates in wet areas for both residential and commercial applications.

The membrane provides anti-fracture protection over shrinkage and other non-structural cracks while maintaining a low permeance rating suitable for steam showers and continuous-use wet environments. The material changes color when cured to help confirm readiness for tile installation.

Key Features

Waterproofing and Crack Isolation: Provides waterproofing and anti-fracture protection over non-structural cracks up to 1/8" (3 mm).
Low Permeance Rating: Rated at 0.38 perms at 20 mils dry thickness when tested to ASTM E96 Procedure E.
Steam Shower Approved: Meets permeance requirements for steam rooms and steam showers without an additional vapor retarder.
Multiple Application Methods: Can be applied by roller, brush, trowel, or sprayer.
Substrate Compatibility: Bonds directly to concrete, masonry, cement backerboard, gypsum-fiber panels, gypsum-based cement toppings, stainless steel, PVC, and ABS drains.
Color-Change Cure Indicator: Changes color during curing to indicate readiness for subsequent installation steps.
Flexible Coat Requirements: One coat on smooth vertical substrates; two coats on rough substrates and all horizontal applications.

Approved Applications

Shower walls and floors
Steam showers and steam rooms
Wet area walls and countertops
Floors requiring crack isolation
Shower pan liner installations (per IPC 417.5.2.5 and UPC 408.7)

Coverage Rates

Waterproofing (Smooth Substrates): 80–100 ft² per gallon with one coat, or 40–50 ft² per gallon with two coats at 15–20 mils wet film thickness per coat.
Crack Isolation (Smooth Substrates): 25–30 ft² per gallon with two coats at 25–30 mils wet film thickness per coat.
Note: Coverage may be reduced on porous or rough substrates.

Specifications

Specification	Details
Product Type	Liquid-applied waterproofing and crack isolation membrane
Compliance	ANSI A118.10, ANSI A118.12
Permeance	0.38 perms at 20 mils dry thickness
Crack Isolation Capacity	Up to 1/8" (3 mm) non-structural cracks
Available Sizes	1 gallon (3.78 L), 3.5 gallons (13.2 L)

USG™ Durock® Liquid Waterproofing & Crack Isolation Membrane provides a single-system solution for waterproofing, vapor control, and crack isolation in tile and stone installations across wet and steam environments.

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