How to Install Fiber Cement Board for Flooring

Fiber cement board for flooring is a durable, moisture-resistant solution ideal for high-traffic areas, wet environments like bathrooms, and spaces requiring a sturdy subfloor for tile or wood finishes. This guide covers everything you need to know about selecting, cutting, and installing fiber cement flooring boards, along with key considerations for structural support and long-term performance.

Why Choose Fiber Cement Board for Flooring?

Fiber cement flooring offers:
✔ Moisture resistance – Perfect for bathrooms, laundry rooms, and basements.
✔ Durability – Withstands heavy loads and resists warping or cracking.
✔ Fire resistance – Non-combustible for added safety.
✔ Versatility – Compatible with tile, wood, or waterproof coatings.

Materials & Tools Required

Before installation, gather:

Fiber cement floorboards
Modified thinset mortar (for subfloor adhesion)
Corrosion-resistant screws or nails (M5x45mm or 1.25” Backer-On screws)
Alkali-resistant fiberglass mesh tape (for joints)
Circular saw with fiber cement blade or scoring knife
Notched trowel, spacers, level, measuring tape
Safety gear (dust mask, goggles)

Step-by-Step Installation Guide

1. Subfloor Preparation

Ensure the subfloor is clean, dry, and level.
For wooden subfloors: Use ⅝” exterior-grade plywood or 23/32” OSB.
For concrete subfloors: Check for moisture issues and repair cracks.

2. Steel Structure & Support (If Needed)

For elevated flooring:

Main beam: 15H steel (for spans up to 8m).
Secondary beam: #10 channel or #63 angle iron.
Welding: Secure beams on at least three sides; grind seams flat before installation.

3. Cutting & Layout

Measure and cut boards using a fiber cement blade or shears.
Layout rules:
Keep boards parallel to the main beam.
Leave 3-5mm gaps between boards and ⅛” from walls.
Stagger joints in a brick pattern (avoid aligning four corners).

4. Installing Fiber Cement Flooring

Apply thinset mortar with a ¼” notched trowel.
Press boards firmly into the mortar.
Fasten with screws/nails every 8” (⅜”–¾” from edges).
Seal joints with fiberglass tape and mortar.

5. Finishing Options

Waterproof coating for wet areas.
Tile installation: Use appropriate thinset and grout.
Wood flooring: Install over the fiber cement base.

Key Installation Tips

✅ Avoid unsupported edges – Ensure full contact with beams.
✅ Pre-drill screw holes to prevent cracking.
✅ Use silicone sealant for expansion gaps.
✅ Cure for 24+ hours before grouting or flooring installation.

Maintenance & Longevity

Inspect periodically for moisture damage or cracks.
Reapply sealant if joints show wear.
Follow manufacturer guidelines for paint or coatings.

Conclusion

Fiber cement board for flooring provides a strong, moisture-proof foundation for tiles, wood, or standalone use. Whether installing over wood subfloors or steel framing, proper adhesive, fastening, and joint treatment ensure lasting performance.