# Cement-Bonded Particle Board for Partitions, Floors and Soffits

> Cement-bonded particle board (CBPB) is a dense, rigid sheet of wood particles bound in Portland cement, made to IS 14276 in India and EN 634-2 in Europe. It is used for dry partitions, raised floor and mezzanine decking, and external soffits where gypsum would fail in moisture. It is heavy, needs carbide tools and screws for cement boards, and its fire class must come from the product's own test.

## What the choice turns on

Cement-bonded particle board, usually shortened to **CBPB**, is chosen where a
dry-built wall, floor or soffit has to survive conditions that would ruin
gypsum or plywood: humidity, occasional wetting, impact, or exposure under a
canopy. It is made from wood particles bound in Portland cement and pressed
into dense, rigid sheets.

The misconception to avoid is that a "cement board" is one product. CBPB,
[fibre cement board](/materials/fibre-cement-board) and
[calcium silicate board](/materials/calcium-silicate-board) are three different
materials with different weights, fire test results and fixing rules. Swapping
one for another on site because "it is all cement board" is how partitions end
up cracked at joints, overweight on a mezzanine, or outside what the fire
strategy assumed. Every one of those is found late, after finishes are on.

## How it compares with other boards

| Property | Cement-bonded particle board | Fibre cement board | Calcium silicate board | Gypsum board |
| --- | --- | --- | --- | --- |
| Make-up | Wood particles in cement | Fibres in cement and silica | Calcium silicate with fibres | Gypsum core, paper or glass-mat faces |
| Weight | Heaviest | Moderate | Light to moderate | Lightest |
| Moisture tolerance | High; not waterproof | High | Good; grade dependent | Poor, except moisture-resistant types |
| Impact resistance | High | Moderate | Moderate | Low |
| Typical uses | Partitions in humid or high-abuse areas, mezzanine decking, floor underlay, soffits | External cladding, soffits, wet-area linings | Fire linings, ceilings, humid areas | Dry office partitions and ceilings |
| Machining | Carbide or diamond tools | Carbide or score-and-snap | Carbide or fine saw | Knife |

For the full range of plasterboard options in dry office areas, see
[gypsum board types](/materials/gypsum-board-types).

## Where it is used

- **Dry wall partitions** in plant rooms, service corridors, warehouses, back
  of house and humid zones, usually on steel studs, where impact or moisture
  would damage gypsum
- **Floor decking and underlay** on steel mezzanines and raised platforms, and
  as a levelling layer under tiles or resilient flooring
- **External soffits and canopy linings**, protected from standing water, where
  the board is sealed and painted as the manufacturer directs
- **Wet-area backing** behind tiles, together with a waterproof membrane

The project's partition and ceiling design sits within
[false ceilings and partitions](/services/interior-fit-out/false-ceilings-and-partitions);
choosing between a solid board wall and glazing is covered in
[glass partition vs drywall partition](/compare/glass-partition-vs-drywall-partition).

## Moisture and fire behaviour

**Moisture.** The cement matrix protects the wood particles, so CBPB swells and
loses strength far less than wood-based panels when damp. It still moves
slightly with moisture and temperature, which is why joints are detailed to
allow movement. It is not a waterproofing layer.

**Fire.** CBPB is much less combustible than resin-bonded boards, but it is
not inert, because it contains wood. Its reaction-to-fire class is a property
of the specific product as tested under **EN 13501-1** or the test the
manufacturer declares. The fire resistance of a partition or floor is a
property of the whole tested system: board, studs, insulation, fixings and
joints. What a particular wall, corridor or escape route requires is decided
under **NBC 2016 Part 4** by the fire consultant and the authority having
jurisdiction.

## Handling, cutting, fixing and joints

- **Weight.** Sheets are heavy. Plan lifting, two-person handling, and stud and
  track spacing to the manufacturer's tables; check mezzanine loads with the
  structural engineer
- **Cutting.** Carbide-tipped or diamond blades with dust extraction and dust
  masks, as the dust contains cement
- **Fixing.** Corrosion-resistant screws made for cement boards, pre-drilled
  near edges, at the manufacturer's spacing; stainless or coated fixings
  externally
- **Joints.** Either an expressed open joint, a cover strip, or a flexible
  sealant joint. Rigid filler over a butt joint usually cracks as the boards
  move
- **Finishing.** Primer suited to an alkaline cement surface before paint;
  tile adhesive suited to cement boards

Board thicknesses are typically chosen by use, thinner for linings and thicker
for floors, and set from the manufacturer's data and the engineer's check.

## Common mistakes

- **CBPB substituted with another "cement board"** without checking weight, fire
  test or fixing details.
- **Rigid-filled joints** that crack within months as the boards move.
- **Drywall screws** that strip, snap or rust.
- **Used as waterproofing** in a shower with no membrane behind the tiles.
- **Mezzanine decking laid at the wrong span** because the joist spacing was
  never checked against the board.
- **Dry cutting indoors** with no extraction, leaving cement dust through the
  services.

## What to ask your contractor or supplier

- Is this cement-bonded particle board to IS 14276, or a different board?
- What is the tested reaction-to-fire class, and is the partition a tested
  system?
- What stud, joist or purlin spacing does the manufacturer allow for this
  thickness?
- How will joints be detailed, and which fixings are proposed?
- How will cutting dust be controlled on an occupied floor?

## Standards referenced

Cement-bonded particle boards under **IS 14276** and, in Europe, **EN 634-2**.
Reaction-to-fire classification under **EN 13501-1**, with building
requirements under **NBC 2016 Part 4**. Board thickness, spans, partition
systems and fire performance for a particular project must be confirmed by the
project's designer, structural engineer and fire consultant.

## Frequently asked questions

### Is cement-bonded particle board the same as fibre cement board?

No. Cement-bonded particle board uses wood particles as the filler in a cement matrix, which makes it thicker, heavier and denser. Fibre cement board uses cellulose or synthetic fibres with cement and silica, usually autoclaved, giving a thinner, lighter sheet. They overlap in use, but their weight, flexibility, machining and fire test results differ, so they are not interchangeable on a drawing.

### Can CBPB be used in wet areas and toilets?

It tolerates moisture far better than gypsum board or wood-based panels and is widely used in humid areas, but it is not a waterproofing layer. In a toilet or shower the board needs a tanking or waterproof membrane under the tiles, and its edges and penetrations need sealing as the manufacturer directs.

### Is cement-bonded particle board fireproof?

No board is fireproof. The cement matrix makes CBPB much less combustible than resin-bonded wood panels, but it does contain wood particles. Its reaction-to-fire class comes from a test of the specific product under a standard such as EN 13501-1, and a partition's fire resistance comes from a test of the complete wall system. What the building needs is decided by the fire consultant under NBC 2016 Part 4.

### Can CBPB be used as a floor?

Yes. Thicker boards are widely used as decking on steel mezzanines, as a dry floor over joists, and as an underlay or levelling layer before tiles, vinyl or carpet. The board thickness and the joist or purlin spacing are set from the manufacturer's span tables and checked by the structural engineer for the actual floor loads.

### How do you cut and fix cement-bonded particle board?

With carbide-tipped or diamond blades and dust extraction, because the dust contains cement. Fix with corrosion-resistant self-drilling or countersunk screws made for cement boards, pre-drilling near edges, at the spacings the manufacturer gives. Hammered nails and ordinary drywall screws tend to crack the edges or corrode.

### Why is CBPB heavier than gypsum board, and does it matter?

Cement is dense, so a CBPB sheet weighs considerably more than a gypsum sheet of the same size. That affects manual handling, studs, track spacing and floor loading on mezzanines. It can also be an advantage, because the extra mass helps with sound insulation and impact resistance.

## Sources

- [IS 14276](https://standards.bis.gov.in/website/published-standards/department-wise) — Cement bonded particle boards — specification
- [EN 634-2](https://standards.cencenelec.eu/ords/f?p=CEN:105) — Cement-bonded particleboards — specifications — requirements for OPC bonded particleboards for use in dry, humid and external conditions
- [EN 13501-1](https://standards.cencenelec.eu/ords/f?p=CEN:105) — Fire classification of construction products and building elements — reaction to fire
- [NBC 2016, Part 4](https://www.bis.gov.in/standards/national-building-code/) — Fire and life safety

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Source: https://hagerstone.com/materials/cement-bonded-particle-board