Where a wall or ceiling has to meet a fire-resistance requirement, 12.5mm fire resistant plasterboard is specified in place of standard wallboard, and buying it in bulk keeps the material cost down on larger fire-rated jobs. This is 12.5mm tapered edge board built around a gypsum core modified with additives that improve its performance in fire, helping to slow the spread of flames and hold back heat for longer than a standard board when it forms part of a correctly built system. It is an internal board for domestic and commercial walls and ceilings where fire protection is called for.

Each board measures 2400mm x 1200mm, covers 2.88m² and weighs around 30kg, a full standard sheet that closes off large areas quickly and falls on 400mm and 600mm stud and joist centres. The tapered long edges are made for taping and jointing: the recess lets scrim tape and jointing compound sit flush with the board face for a smooth, paint-ready finish, and the board also takes a plaster skim across the whole face where that is preferred. It fixes with standard tools, screwed back to timber or metal stud frames as part of a fire-rated wall or ceiling build-up.

The fire performance comes from the core rather than any coating. The modified gypsum holds chemically combined water that is released as steam under heat, slowing the temperature rise on the protected side and buying time in a fire. That makes this the board to reach for on protected escape routes, garage-to-house separating walls, service risers and any partition or ceiling where the specification calls for a fire-resistant lining, rather than the standard wallboard used elsewhere.

Fire resistance is a property of the complete wall or ceiling system, not of the board on its own, so 12.5mm fire resistant plasterboard should be installed within a tested system, in line with the manufacturer's guidance, the project fire strategy and Building Regulations. Ordering in bulk suits larger fire-rated fit-outs, multi-plot new build and repeat trade work, where lining a lot of protected area at a lower cost per board makes a real difference to the material bill.

Key Benefits of 12.5mm Fire Resistant Plasterboard:

• 12.5mm fire resistant gypsum plasterboard for internal walls and ceilings where a fire-resistance requirement is specified.
• Gypsum core modified for enhanced fire resistance, helping to slow the spread of flames within a suitable system.
• Tapered long edges for taping and jointing to a flush, paint-ready finish, or a full plaster skim.
• 2400mm x 1200mm full sheet covering 2.88m², sized to suit 400mm and 600mm stud and joist centres.
• Around 30kg per board, so plan handling and lifting accordingly.
• Fixes with standard tools, screwed to timber or metal stud frames as part of a fire-rated build-up.
• Suitable for domestic and commercial internal walls and ceilings requiring fire protection.
• Compatible with standard taping, jointing and plaster finishes.
• Insulation UK own-brand board bought in bulk, at a lower cost per board on larger orders.

Good to know:

• Fire resistance is a system property. The board contributes to a fire-rated wall or ceiling; the rating achieved depends on the full tested build-up, not the board alone.
• Check the fire classification before you specify. Confirm the required class and system against the manufacturer datasheet, fire classification information and your project fire strategy.
• Tapered on the long edges only. Cut ends and board ends butt together, so tape and fill those joints as you would any butt joint.
• Heavier than standard wallboard. At around 30kg a sheet, lift in pairs and store flat, off the ground and dry.
• Not moisture resistant. For bathrooms, wet rooms or damp spaces that also need fire performance, specify a board rated for both.

For lining fire-rated walls and ceilings across a whole job, 12.5mm fire resistant plasterboard is the board to buy in quantity: a standard-size, taping-and-jointing board that fixes fast, finishes cleanly and costs less per sheet the more you order.