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At a Glance
Why Choose This Product
Factory-bonded WATER-STOP membrane on both sides
Accepts direct tile installation with thin-set mortar
Tongue and groove edges eliminate banding in standard wet areas
Installs over wood studs, metal studs, drywall, and existing tile
Suitable for steam showers with seam banding and sealant
Meets ANSI A118.10, ANSI A118.12, and IAPMO PS106
Product Information
The GURU® W-S Board is a waterproof tile backer board featuring a high-density XPS foam core with a factory-bonded WATER-STOP membrane on both sides. The integrated membrane extends beyond the board edges to create a waterproof flange that simplifies seam treatment while providing a tile-ready substrate for ceramic, porcelain, and natural stone installations.
Designed for shower walls, tub surrounds, and other wet area wall assemblies, W-S Board installs over wood studs, metal studs, drywall, and existing tile surfaces. Tongue and groove edges eliminate the need for banding in standard wet area installations, while steam shower applications require seam banding and sealant for complete waterproofing.
The factory-bonded waterproof membrane eliminates the need for an additional surface waterproofing membrane before tile installation. The board accepts direct thin-set mortar application and meets ANSI A118.10, ANSI A118.12, and IAPMO PS106 performance standards for waterproofing and crack isolation.
W-S Board is suitable for shower wall installations, tub surrounds, wet area wall assemblies, tile-over-tile renovation projects, and other waterproof tile backer applications where a lightweight, waterproof substrate is required.
Product Resources
Common Questions
GURU W-S Board is designed as a waterproof tile backer board for shower walls, wet area walls, tub surrounds, and tile-over-tile renovation projects.
No. The board features a factory-bonded WATER-STOP membrane on both sides, creating a waterproof, tile-ready surface without requiring an additional surface waterproofing membrane.
Yes. The board can be installed over existing tile, drywall, wood studs, and metal stud framing when installed according to the manufacturer's instructions.
For standard wet area installations, the tongue and groove edges eliminate the need for banding. Steam shower installations require seam banding and sealant.
Yes. The factory-bonded WATER-STOP membrane provides a tile-ready surface that accepts direct installation with thin-set mortar.
The board is manufactured with a waterproof XPS foam core bonded to a WATER-STOP membrane on both faces.
W-S Board complies with ANSI A118.10, ANSI A118.12, and IAPMO PS106.
Yes. It is suitable for steam shower applications when the seams are treated with the required banding and sealant.
