Gypsum Board Types — Regular, Moisture and Fire

Gypsum board is a gypsum core faced with paper liner, made in regular, moisture resistant, fire resistant, impact resistant and acoustic grades that vary the core additives and liner. A partition's fire and acoustic rating belongs to the complete tested system, not to the board grade alone.

By Dhruv Agarwal · · 1 min read

What it is

A gypsum core faced with paper liner, produced in grades that vary the core additives and the liner to suit different duties.

The grades

GradeIdentifying colour (typical)Use
RegularIvory / grey linerGeneral partitions and ceilings
Moisture resistantGreenPantries, humid areas, wet-area backing
Fire resistantPink / redWithin tested fire-rated systems
Impact resistantVariesCorridors, schools, high-traffic areas
Acoustic / high densityVariesWhere partition sound rating matters

Colours vary by manufacturer and should never be the basis of specification — the grade and standard reference should be.

The system, not the board

A partition's fire rating, acoustic rating and structural performance are properties of the complete tested assembly:

  • Board type, thickness and number of layers
  • Stud gauge, depth and centres
  • Insulation type and density in the cavity
  • Screw type, length and spacing pattern
  • Joint staggering between layers
  • Head, base and junction detailing

Substituting any one of these breaks the test. On a fire-rated wall that is not a paperwork issue — it is the wall not doing what the fire strategy assumes.

Where projects go wrong

  • Fire board in an untested arrangement, assumed to give a rating.
  • Moisture resistant board inside showers, where cement board is required.
  • Screw spacing widened to save time, changing the tested system.
  • Joints not staggered between layers in double-layer systems.
  • Boards installed before the building is dry, so they absorb moisture and sag.

Standards referenced

Gypsum plaster boards under IS 2095 (Part 1) and EN 520. Fire and life safety provisions under NBC 2016, Part 4.

Standards referenced

  • IS 2095 (Part 1) — Gypsum plaster boards (Bureau of Indian Standards)
  • NBC 2016, Part 4 — Fire and life safety (Bureau of Indian Standards)
  • EN 520 — Gypsum plasterboards — definitions and requirements (CEN-CENELEC)

Frequently asked

No, and this is the most consequential misunderstanding in drywall. The rating belongs to the tested system — specific board type and thickness, specific stud spacing and gauge, specific insulation, specific screw pattern, specific joint treatment. Change any element and the tested rating no longer applies. Buying fire board and then building the partition however is convenient produces an untested wall with no defensible rating.

Pantries, washroom dry zones, areas subject to occasional humidity, and as a backing where minor dampness is expected. It is water resistant, not waterproof, so it is not the correct substrate inside a shower or behind wet-area tiling — that needs cement or calcium silicate board with a separate waterproofing membrane over it.

12.5mm is the general standard for partitions and ceilings, with 15mm used where higher fire resistance, better acoustics or greater impact resistance is required, and double layering used in tested systems for higher ratings. Thickness follows from the tested system being specified rather than being chosen independently, which is why the system reference matters more than the board thickness alone.

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