What kind of plywood is best for a ceiling?
For a dry room, an interior-grade panel with a smooth face for paint works well. For a bathroom, kitchen, or basement, choose a water-resistant WBP or MR bond. In any enclosed room, ask for a low formaldehyde emission class such as CARB Phase 2 or EN 13986 E1, since the panel sits above the air you breathe.
How thick should plywood be for a ceiling?
Thickness follows your support spacing. As a starting point, 12 mm plywood suits framing at about 400 mm centres and 18 mm suits framing at about 600 mm centres. Thinner panels on wider centres tend to sag. Let the project engineer confirm the final thickness and fixing schedule for your structure.
Is a plywood ceiling waterproof?
No. Plywood is water-resistant, not waterproof, and the glue line carries that rating. A WBP bond handles regular humidity in a bathroom or kitchen far better than an interior MR bond, but no plywood ceiling should be treated as a waterproof surface.
Plywood or drywall for a ceiling?
Drywall is cheaper, faster, and more fire-resistant, so it suits plain painted ceilings. Plywood wins on durability, on curved or feature soffits, and where a visible wood face is the point. Many projects use gypsum across the general area and plywood on the feature ceiling.
Does a plywood ceiling need fire treatment?
It depends on the building. Untreated plywood burns, and a fire engineer will check its flame-spread rating against the room's requirement. A domestic living-room ceiling rarely needs treatment; a public or commercial building often specifies a reaction-to-fire class, and fire-retardant-treated plywood is available for those cases.
