End-coat
End-coat is a primer applied to cut edges of fibre cement cladding before installation. Omitting it is the most common single defect on FC cladding sites.
Ask Chalkline about this →End-coat (also called cut-end primer or end sealer) is a manufacturer-supplied primer applied to every freshly cut edge of a fibre cement cladding panel or board before installation. Fibre cement is manufactured with sealed faces and edges; when cut on site, the raw cellulose fibre at the cut surface is exposed and will absorb moisture if left unprimed, causing edge swelling, face cracking, and in repeated wet-dry cycles, surface delamination.
The typical application is brush-on or roller-on immediately after cutting, with installation following once the primer has set. Most major manufacturers (James Hardie, Cemintel) supply a product-specific end-coat matched to the cladding system. Generic exterior primers may be used where the manufacturer’s guide permits, but using an incompatible primer can compromise adhesion of the paint system at the edge.
Omitting end-coat is the most common single defect on fibre cement cladding sites. The failure typically presents within one to two weather cycles as a fine crack running along the cut edge, which can then allow bulk water entry behind the sheet.
Also known as: cut-end primer, end sealer.
Category: External cladding / fibre cement.
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Last updated: 2026-05-10. Verified: 2026-05-10. Quarterly review for currency.