FIBEROCK Brand 3-ft x 5-ft x 1/4-in Waterproof Gypsum Backer Board 1.0 Sheets

Charlotte Wood Middle School, Danville, California

It was 1991, and our company was framing the entire middle school. The Charlotte Wood Middle School was built out of Douglas Fir Lumber, Pressure Treated Plates, and different kinds of Plywood. I negotiated a contract with a lumber mill in Oregon to provide all the dimensional lumber for the project. I had lumber being delivered from their mill for months. GREAT PROJECT! Rick Aguilar - Cost Estimator

Overview

• Key Specs & Features (¼-inch version)

  • Size: 3 ft × 5 ft (36 in × 60 in)

  • Thickness: ¼-inch (~0.25 in)

  • Material: Fiber-reinforced gypsum with integral water- and mold-resistance (“Aqua-Tough / Underlayment”)

  • Weight: ~ 24 lbs per sheet

  • Coverage: about 15 sq ft per sheet (3 × 5)

  Best Uses:

  • Underlayment for Tile Floors – Perfect as a thin, stable base under ceramic, porcelain, or stone tile without raising floor height too much.

  • Bathroom & Laundry Floors – Provides moisture-resistant support in areas with splashes, humidity, or occasional spills.

  • Kitchen & Entryway Floors – Helps protect subfloors from incidental moisture under tile or resilient flooring.

  • Backsplashes & Wainscoting – A thin, durable substrate for tile in kitchens and bathrooms where space is limited.

  • Basement Renovations – Works as an underlayment beneath finished flooring to handle damp conditions.

  • Transition Projects – Ideal when remodeling, where a ½-inch board would create uneven transitions with adjacent flooring.

  ⚠️ Note: While it’s moisture-resistant, ¼-in Fiberock is not recommended for constant water exposure (like inside shower or steam room walls/floors). For those applications, use ½-in Fiberock AquaSmart, DensShield, or cement board with a waterproofing membrane.

  Practical Project Ideas for Homeowners:

  • Tile a Bathroom Floor – Use as an underlayment to give your tile a strong, moisture-resistant base.

  • Refresh a Laundry Room – Protect subfloors under tile or vinyl in high-humidity laundry spaces.

  • Install a Kitchen Backsplash – Provides a thin, durable surface for glass, ceramic, or stone tile.

  • Upgrade a Mudroom Entryway – Adds durability and moisture resistance under tile where wet shoes and coats are common.

  • Basement Flooring Project – Lay under tile or vinyl to guard against damp basement conditions.

  • DIY Half-Wall Wainscoting with Tile – Create a splash-resistant accent wall in bathrooms or utility rooms.

  • Small Powder Room Remodel – Ideal for tight spaces where you need tile durability without raising the floor height too much.

• Why Choose Waterproof Gypsum Backer Board?

  • Superior Water & Mold Resistance
    The panel uses an Aqua-Tough / AquaSmart technology, with a uniform, specially engineered composition that resists moisture and mold throughout the board—not just the surface.

  • Dimensional Stability
    Less tendency to warp, swell, or delaminate compared to wood-based underlayments (like plywood, OSB, lauan). That means better long-term performance, especially where moisture fluctuations happen.

  • Smooth, Flat Surface for Finishes
    The face is uniform, without a paper facer that can tear, delaminate or absorb water. It’s excellent under tile, stone, or even flooring & can be painted in transition areas.

  • Lightweight & Easier to Handle / Install
    At ¼-inch thickness, this version is slimmer and lighter, which makes cutting, fitting, and positioning much easier, especially for DIY or tight spaces. Less strain, fewer helpers needed.

  • Multi-Use Versatility
    Works in both wet and dry areas across the home. You can use it under tile, vinyl, hardwood, laminate, even carpeting in some situations. Great for kitchens, bathrooms, entry ways, etc.

  • Environmentally Friendly
    High recycled content (≈ 95%) in many versions, making it a greener option compared to many other backer products.

  • Warranty & Reliability
    Comes with a 20-year limited warranty (depending on the specific product line) against defects like buckling, warping, delamination, cracking or splitting once properly fastened.

  When This Board Really Shines

  • When you need a stable, moisture-resistant underlayment but want minimal build-up (so a ¼-inch board helps reduce height issues).

  • For renovation projects where transitions to existing flooring are tight.

  • Kitchens, bathroom floors (not the wettest zones like shower pans), laundry rooms, mudrooms, etc.

  • Anywhere you want both tile bonding strength and easier handling (lighter board, less mess).

Ask Rick, example:“What’s the best Gypsum Board for this application? or “ When should I use fire-rated (Type X) drywall?”

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