The Ontario Building Code | Continuity of Firewalls

3.1.10.3. Continuity of Firewalls

(1) A firewall shall extend from the ground continuously through, or adjacent to, all storeysof a building or buildingsso separated, except that a firewall located above a basement storage garageconforming to Article 3.2.1.2. is permitted to commence at the floor assembly immediately above the storage garage.

(2) A firewall is permitted to terminate on the underside of a reinforced concrete roof slab provided,

(a) the roof slab on both sides of thefirewall has a fire-resistance rating not less than,

(i) 1 h if the firewall is required to have a fire-resistance rating not less than 2 h, or

(ii) 2 h if the firewall is required to have a fire-resistance rating not less than 4 h, and

(b) there are no concealed spaces within the roof slab in that portion immediately above the firewall.