FIBEROCK Brand 3-ft x 5-ft x 1/2-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

• What It Is

  • Brand / Line: FIBEROCK® Brand, AquaSmart™ (Tile Backerboard) from USG.

  • Size & Thickness: Nominally ~ ½-inch; however the more recent panel thickness is 0.42-inches for ½-in boards.

  • Dimensions: 3 ft × 5 ft sheet size.

  • Core Composition: Fiber-reinforced gypsum with a homogeneous waterproof / water-resistant core in newer AquaSmart versions. No paper facer that can easily delaminate.

  Key Features & Performance

  Waterproof / Water-Resistance Meets ANSI 118.10 (Sec 4.5) for waterproofness. This means the core is built to resist water penetration.

  Mold & Mildew Resistance Mold / mildew resistant core / materials, designed to perform well in wet / damp areas.

• Fire Rating Class A flame spread per ASTM E84; good fire performance.

• Environmental / Sustainability~97% recycled content. Greenguard certified.

• Tile Bond / Bond Strength Excellent adhesion to tile / stone / thinset; uniform composition helps with good bonding.

• Ease of Handling / Installation Lighter than many cement boards, easier to cut / snap / carry.

  Physical Data & Usage Specs

  • Coverage Area: A 3×5 sheet gives ~15 sq ft coverage.

  • Weight: Roughly in the 30-35 lb range depending on thickness and moisture. (0.42-in version weights ~35 lbs for a 3×5 size sheet)

  • Edges: Typically square edges. Joints & ends are treated per manufacturer’s instructions (fastening, taping, etc.).

  Best Uses:

  • Ideal / Appropriate Uses

    • Interior wet and dry areas behind tile or stone: showers (walls, not pans unless certified), tub surrounds, splash zones.

    • Under tile or stone countertops.

    • Flooring underlayment (with proper support and fastener spacing) in areas with some moisture exposure but not constant standing water.

    • Transition surfaces where tile meets painted wall or other finish; this board can serve as substrate for both.

    Limitations / Things to Know

    • Even though it’s waterproof per ANSI 118.10, areas with continuous standing water or extreme humidity (steam rooms, saunas, etc.) may require additional membranes or cementitious boards.

    • Fastener spacing, framing deflection, substrate stability all matter — performance depends heavily on proper installation.

    • Should be installed properly (cut edges, sealed joints, correct thinset / adhesive). Manufacturer’s warranty & specs must be followed.

  Practical Project Ideas for Homeowners:

  • It’s a fiber-reinforced gypsum panel with a waterproof (or water-resistant) core.

  • It does not use paper facers that can tear or delaminate. That improves durability in wet areas.

  • Approved for wet and dry areas: showers, bathroom walls, kitchen backsplashes, etc.

  • Works as underlayment or backer for tile, vinyl, carpeting, hardwood, laminate.

  • Fairly lightweight for its strength: easier to cut, handle, install compared to many cement boards.

• Why Choose Waterproof Gypsum Backer Board?

  • True Waterproof Composition

    • The board meets ANSI 118.10 (Section 4.5) for waterproofness. That means it isn’t just water-resistant on the surface — the waterproof performance is throughout the panel.

    • It does not have paper facers that can tear, delaminate, or get damaged in moist conditions.

  • Durability & Mold / Mildew Resistance

    • Because of its uniform, fiber-reinforced gypsum core and waterproof makeup, it resists swelling, warping, mold, mildew, and deterioration that are common issues with traditional wood-based or non-waterproof gypsum boards.

    • It’s designed to work in wet and dry areas of the home (walls, floors, countertops, etc.).

  • Weight & Easy Handling / Installation

    • It’s lighter than many traditional cement backer boards, making it easier to cut, carry, and fasten.

    • Cuts cleanly: score-and-snap or a saw; handles well when dealing with jobsite conditions.

  • Strong Tile Bond / Versatility for Flooring / Finish Options

    • The panel is engineered to provide a superior bond to tile or stone.

    • Works across different finish materials: tile, stone, vinyl, hardwood, laminate, carpeting, or painted wall surfaces. This makes it a flexible substrate.

  • Sustainability

    • The product is made with a high recycled content (often cited as 95-97% recycled material) in many versions.

    • Free of many resins, adhesives or solvents that can cause staining or off-gassing.

  • Warranty & Certifications

    • There is a 20-year limited warranty on many of the Fiberock AquaSmart / AquaTough backerboard products.

    • Meets relevant ASTM & ANSI standards (e.g. mechanical strength, water absorption), and has tests for fire resistance, mold, etc.

  When This Board Really Shines

  • 1. Wet & Humid Environments

    • Showers and Tub Surrounds
      The waterproof core and lack of paper facers make it much more resistant to swelling, mold, and mildew than standard drywall or even “green board.”

    • Bathrooms, Laundry Rooms, and Utility Spaces
      In areas where condensation, leaks, or splashes are common, it provides long-term durability without warping.

    👉 Why it shines here: Traditional drywall deteriorates quickly in moisture; cement board is water-resistant but heavy and harder to handle. Fiberock combines moisture protection with easier handling.

    2. Tile & Stone Installations

    • Kitchen Backsplashes
      A smooth, stable surface for tile, resistant to steam and cooking splatter.

    • Flooring Underlayment (for tile, vinyl, or stone over wood subfloors)
      Creates a strong, flat substrate that resists movement and gives tiles better adhesion.

    • Countertops
      Perfect as a tile backer under granite, quartz, or ceramic tile counters, especially near sinks.

    👉 Why it shines here: Provides a superior bond for thinset and adhesives compared to plywood or paper-faced gypsum. It’s also lighter and less brittle than cement board.

    3. DIY & Remodeling Projects

    • Quick Kitchen or Bath Updates
      Easy to cut (score-and-snap), lighter to carry, and simpler for one person to install compared to cement board.

    • Small Custom Features (niches, benches, recessed shelves)
      Cuts cleanly without crumbling, making it great for detail work.

    👉 Why it shines here: Homeowners who want professional durability without the frustration of handling heavy, dusty cement boards will find it more user-friendly.

    4. Long-Term Durability & Peace of Mind

    • Homes in Damp Climates
      Fiberock resists mold/mildew growth, helping protect indoor air quality.

    • Multi-use Rooms
      Can transition from tiled zones to painted zones smoothly without switching substrates.

    • Warranty Confidence
      Backed by a long-term manufacturer warranty (often 20 years).

    👉 Why it shines here: It protects against the hidden costs of moisture damage — repairs, mold remediation, and tile failures.

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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