Standard vs Fire-Rated Plasterboard

Fire-rated plasterboard is required in: party walls between dwellings (30 or 60 min), walls and ceilings around protected staircases, garage walls and ceilings adjoining habitable rooms (30 min), loft conversions (30 min to new rooms), and walls enclosing flats (60 min). Approved Document B specifies the fire resistance periods for different building elements.

Fire-rated plasterboard (e.g. Gyproc FireLine, Knauf Fire Panel) contains glass fibres and other additives mixed into the gypsum core that maintain the board integrity at high temperatures. Standard plasterboard crumbles when the water of crystallisation evaporates. The pink colour is an industry convention to identify fire-rated boards on site.

Fire-rated plasterboard costs approximately 30-50% more than standard. A standard 2400x1200x12.5mm board costs £4-6, while a fire-rated 2400x1200x12.5mm board costs £6-9. The 15mm fire-rated board costs £7-10. For most projects, the material cost difference is modest — a loft conversion might need £50-100 extra in board costs.

Fire-rated plasterboard is slightly harder to cut than standard board due to the glass fibre reinforcement. A standard Stanley knife works but dulls faster — change blades more frequently. The glass fibres can cause minor skin irritation when cutting, so gloves are recommended. Fixing, taping and jointing are identical to standard board.

Not exactly, but two layers of 12.5mm standard board can provide approximately 30 minutes fire resistance. However, this is not a like-for-like replacement for a tested fire-rated system. Building control typically requires the specific board type specified in the tested system (e.g. British Gypsum White Book specifications). Using fire-rated board as specified ensures compliance and warranty.