Mastic
Mastic is a thick, paste-like adhesive or sealant used in construction to bond panels, seal joints, and fill gaps. Common as a panel adhesive and cornice compound.
Ask Chalkline about this →Mastic is a general construction term for a thick, paste-like adhesive or sealant that stays workable long enough to be applied by gun, trowel, or brush, then cures to a firm or flexible bond. On a residential site, the word is used for two distinct products: mastic adhesive (used to bond boards, panels, and trim to framing or masonry) and mastic sealant (used to seal joints and gaps).
In the context of construction adhesives, mastic typically refers to solvent-based synthetic rubber (SBR) panel adhesives such as Selleys Liquid Nails, used for fixing plasterboard, cement sheet, particleboard, and skirting to timber or masonry. These were the subject of the now-withdrawn Australian Standard AS 2329-1999, Mastic adhesives for fixing wallboards.
The term is sometimes used loosely to include any thick, gun-applied adhesive or gap filler; confirm the product type (adhesive or sealant) and its chemistry before specifying.
Also known as: mastic adhesive, mastic sealant
Category: Adhesives and sealants
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Last updated: 2026-05-09. Verified: 2026-05-09. Quarterly review for currency.