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Mineral Fiber vs Fiberglass Ceiling Tiles

The two dominant ceiling tile materials in commercial construction. They look similar from the ground, but the performance differences matter — especially for acoustic-critical and moisture-prone spaces.

What They're Made Of

Mineral fiber tiles are made from a wet-felted mix of slag wool (a steel manufacturing byproduct), perlite, recycled paper, and binding agents. The slurry is formed into boards and dried. This has been the standard commercial ceiling tile material for 60+ years.

Fiberglass tiles are made from glass fibers bonded together with a thermosetting resin. The resulting board is lighter, more dimensionally stable, and has better acoustic properties than mineral fiber at the same thickness.

Acoustic Performance

This is the biggest differentiator. Fiberglass absorbs more sound than mineral fiber across the frequency spectrum:

  • Mineral fiber NRC range: 0.50–0.70 for standard products. Armstrong Cortega: NRC 0.55. USG Radar: NRC 0.55.
  • Fiberglass NRC range: 0.70–0.95. Armstrong Ultima: NRC 0.70. CertainTeed Symphony: NRC 0.70. USG Halcyon: NRC 0.80.

For spaces where acoustic performance drives the spec — classrooms meeting ANSI S12.60, open offices needing maximum absorption, or healthcare facilities with speech privacy requirements — fiberglass is the better performer.

For detailed ratings, see our NRC and CAC guide.

Moisture Resistance

Fiberglass wins here too. Mineral fiber tiles absorb moisture and can sag, stain, or warp in humid environments. Most mineral fiber tiles are rated for 70% RH (relative humidity). Some specialty mineral fiber products handle 90% RH.

Fiberglass tiles typically handle 90–99% RH without sagging. They don't absorb water the way mineral fiber does. For kitchens, natatoriums, coastal buildings, and any space with humidity concerns, fiberglass is the safer choice.

Related: what to do when tiles get water damaged.

Weight

Fiberglass tiles are lighter. A typical 2×2 mineral fiber tile weighs 2–3 lbs. The same size fiberglass tile weighs 1–2 lbs. The weight difference matters in seismic zones (lighter tiles = less seismic load on the grid) and for large installations where material handling adds up.

Appearance

From the ground, a white mineral fiber tile and a white fiberglass tile look nearly identical. The texture differs slightly — mineral fiber has a more porous, textured surface while fiberglass tends toward a smoother, more refined face. Premium fiberglass tiles (Ultima, Symphony) have a distinctly cleaner appearance than basic mineral fiber.

Light reflectance is similar between the two materials — both hit 0.83–0.90 for white tiles. See our energy efficiency guide for why this matters.

Sound Blocking (CAC)

Mineral fiber tiles generally have higher CAC ratings than fiberglass. The density of mineral fiber blocks more sound from passing through. Typical CAC for mineral fiber: 33–40. Typical CAC for fiberglass: 30–35.

If speech privacy between adjacent rooms is the priority (medical offices, law firms, HR offices), mineral fiber's higher CAC is an advantage. Read about HIPAA acoustic privacy for healthcare applications.

Cost

Mineral fiber is cheaper. Basic mineral fiber tiles (Cortega, Radar, BET-197) run $0.80–$2.00/SF for the tile. Fiberglass tiles (Ultima, Symphony, Halcyon) run $2.50–$6.00/SF. Fiberglass costs 2–3× more per square foot for the material.

The grid, labor, and accessories are the same regardless of tile material. In a typical installation, the tile represents 30–40% of the total cost, so going from mineral fiber to fiberglass might increase total installed cost by 25–50%. See our cost guide.

Sustainability

Both materials are recyclable through manufacturer programs. Armstrong and USG accept old mineral fiber tiles for recycling into new tiles. Fiberglass recycling infrastructure is less established but growing. Both materials carry EPDs and can contribute to LEED credits.

Mineral fiber has higher recycled content (25–80% typical). Fiberglass recycled content is lower (20–40% typical). Read our recycling guide.

When to Choose Each

Choose Mineral Fiber When:

  • Budget is the primary driver
  • Sound blocking (CAC) matters more than sound absorption (NRC)
  • The space has controlled humidity (standard office HVAC)
  • The project is utilitarian — basic offices, corridors, retail

Choose Fiberglass When:

  • Maximum acoustic absorption is needed
  • Humidity is a concern (healthcare, kitchens, coastal)
  • A refined appearance is specified
  • The space has specific NRC requirements (classrooms, open offices)
  • Weight matters (seismic, long-span grid)

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