15mm Standard Plasterboard Wallboard is the thickest board in the standard range, a gypsum board for lining internal walls, partitions and ceilings where an ordinary 12.5mm sheet does not give quite enough rigidity or mass. It carries a tapered edge for a taped-and-jointed flush finish, and the extra thickness firms up the wall, steadies ceilings across wider spans and nudges up general and acoustic performance.

The full 2400mm x 1200mm sheet covers 2.88m² and sits to 400mm and 600mm centres, but weight is the thing to plan for: as the heaviest board in the range, a 15mm sheet is a two-person lift, and a board lifter is worth having for ceilings. Under the ivory paper face sits a non-combustible gypsum core that carries inherent fire resistance and takes a skim or direct decoration once the joints are filled. Fixing is standard: drywall screws to timber or metal stud, or dot and dab onto masonry, blockwork or brick.

What the extra millimetres buy you is rigidity. The added core mass stiffens the board across a span, which is why 15mm earns its place on ceilings where joists run at wider centres and a thinner sheet would be more at risk of sagging, and on partitions meant to feel solid rather than hollow. The tapered long edges finish the same way as the rest of the range: scrim taped and filled flush for a seamless, paint-ready face, or skimmed over if you would rather plaster the lot.

Across new build and refurbishment, 15mm tapered edge board goes onto stud partitions, wall linings and ceilings where the job wants a heavier, more rigid standard board than 12.5mm. Install it in line with the manufacturer's guidance and your project specification. Where a rated fire performance, a specified sound reduction or moisture resistance is required, a specialist board is the right call instead.

Key Benefits of 15mm Tapered Edge Plasterboard:

• 15mm gypsum plasterboard, the thickest board in the standard range, for internal walls, partitions and ceilings.
• Tapered long edges designed for taping and jointing to a flush, seamless finish.
• More rigid and robust than a 9.5mm or 12.5mm board, for a solid-feeling wall.
• Extra thickness helps on ceilings at wider joist centres and lifts general and acoustic performance over thinner boards.
• Ivory paper face ready for a skim plaster finish, paint or a textured finish.
• Non-combustible gypsum core offering inherent fire resistance.
• 2400mm x 1200mm full sheet covering 2.88m², sized to suit 400mm and 600mm stud and joist centres.
• Screw-fixes to timber or metal stud frames, or bonds to masonry, blockwork or brick by dot and dab.
• Insulation UK own-brand board at competitive trade pricing, with bulk pricing available.

Good to know:

• The thickest, heaviest board. More rigid than 9.5mm or 12.5mm, which steadies ceilings at wider joist centres and stiffens partitions; the cost is weight, so plan a two-person lift.
• Extra mass, not a rating. The thickness lifts general and sound performance, but for a specified fire or acoustic rating use the appropriate board within a tested system.
• Recessed long edges only. The taper runs down the two long sides for tape and fill; ends and cut edges butt together and are jointed like any square joint.
• Skim optional. Taped and jointed, it is ready to paint; skim the full face instead if you want a plastered finish.
• Not for wet areas. For bathrooms, wet rooms or damp, unheated spaces, choose a moisture-resistant board.
• Keep it flat and dry. Store boards flat, off the ground and protected from damp before fixing.

When 12.5mm is not rigid enough and the job still calls for a standard board, 15mm tapered edge plasterboard is the step up: heavier and stiffer, with the same flush taped finish. If the job needs a rated fire performance, dedicated acoustic insulation or moisture resistance, see our specialist plasterboard range, including acoustic plasterboard and fire-rated boards.