Knauf Plasterboard Square Edge 12.5mm | 2.4m x 1.2m

This Knauf 12.5mm square edge plasterboard sheet is designed for lining internal walls and ceilings. It provides a smooth, stable surface ready for skimming or direct decoration and offers good levels of fire, acoustic and thermal performance for domestic and commercial projects.

Yes. The 12.5mm board thickness is suitable for most standard internal partitions and ceiling applications. When used on ceilings, ensure joist spacing and fixing centres follow current guidance so the boards remain flat and well supported.

You can either skim the plasterboard with a finishing plaster or tape and joint the seams, then prime and paint. Many installers choose to tape and joint, apply a suitable sealer or mist coat and then paint directly, which can be quicker than a full skim.

Yes. Before painting, seal the bare plasterboard with a suitable drywall sealer or a watered-down emulsion mist coat. This helps prevent over-absorption, gives an even finish and improves paint adhesion. Avoid using PVA as a sealer for paint.

Standard Knauf plasterboard can be used in kitchens and bathrooms with normal levels of moisture, provided it is properly tiled, sealed and ventilated. For areas with frequent or heavy exposure to moisture, such as shower enclosures, a moisture-resistant or cement-based board is usually recommended.

As a general guide, fix plasterboard at around 300mm centres along the edges and intermediate supports, using appropriate drywall screws. Follow Knauf’s installation guidance and relevant building regulations for exact fixing patterns on walls and ceilings.

Each sheet is 12.5mm thick, 2400mm long and 1200mm wide, giving a coverage of approximately 2.88m² per board. This makes it convenient for standard room heights and common stud spacings.

You can tile directly onto plasterboard in many dry and some wet areas, provided the board is securely fixed, primed where required and the combined weight of tiles and adhesive does not exceed recommended limits. In very wet zones, consider moisture-resistant or tile backing boards and always follow tiling and manufacturer guidance.

Score the face paper with a sharp knife along a straightedge, snap the board along the score and cut the backing paper. Wear suitable PPE such as gloves, eye protection and a dust mask when cutting or sanding, and lift boards carefully as they are relatively heavy.

Standard Knauf plasterboard contributes to the fire performance of a wall or ceiling system because of its gypsum core, but overall fire resistance depends on the full system design, number of layers and framing details. For higher fire ratings, check Knauf system specifications or use dedicated fire-resistant boards.