The Ontario Building Code | Panel Cladding
9.27.9.3. panel Cladding
(1) Hardboard cladding applied in panels shall have all edges supported with not less than a 5 mm gap provided between sheets.
(2) Vertical joints in cladding described in Sentence (1) shall be protected with batten strips or caulking when the joints are not matched.
(3) Horizontal joints in cladding described in Sentence (1) shall be lapped not less than 25 mm or shall be suitably flashed.