Section 1206. Roof Construction and Covering. —

1. Roof Covering. — Roof covering for all buildings shall be either fire-retardant or ordinary depending upon the fire-resistive requirements of the particular type of construction. The use of combustible roof insulation shall be permitted in all types of construction provided it is covered with approved roof covering applied directly thereto.

2. Roof Trusses. — All roofs shall be so framed and tied into the framework and supporting walls so as to form an integral part of the whole building. Roof trusses shall have all joints well fitted and shall have all tension members well tightened before any load is placed in the truss. Diagonal and sway bracing shall be used to brace all roof trusses. The allowable working stresses of materials in trusses shall conform to this Code. Camber shall be provided to prevent sagging.

3. Attics —

   1. Access. — An attic access opening shall be provided in the ceiling of the top floor of buildings with a combustible ceiling or roof construction. The opening shall be located in a corridor or hallway of buildings of three or more storeys in height, and readily accessible in buildings of any height. An opening shall not be less than 600 millimeters square or 600 millimeters in diameter. The minimum clear headroom of 800 millimeters shall be provided above the access opening. For ladder requirements, refer to the Philippine Mechanical Engineering Code.

   2. Area Separation. — Enclosed attic spaces of combustible construction shall be divided into horizontal areas not exceeding 250 square meters by fire-resistive partitions extending from the ceiling to the roof. Except, That where the entire attic is equipped with an approved automatic fire-extinguishing system, the attic space may be divided into areas not to exceed 750 square meters. Openings in the partitions shall be protected by self-closing doors.

   3. Draft Stops. — Regardless of the type of construction, draft stops shall be installed in trusses roofs, between roof and bottom chords or trusses, in all buildings exceeding 2000 square meters. Draft stops shall be constructed as for attic area separations.

   4. Ventilation. — Enclosed attics including rafter spaces formed where ceilings are applied direct to the underside or roof rafters, shall be provided with adequate ventilation protected against the entrance of rain.

4. Roof Drainage System.—

   1. Roof Drains. — Roof drains shall be installed at low points of the roof and shall be adequate in size to discharge all tributary waters.

   2. Overflow Drains and Scuppers. — Where roof drains are required, adequate overflow drains shall be provided.

   3. Concealed Piping. — Roof drains and overflow drains, when concealed within the construction of the building, shall be installed in accordance with the provisions of the National Plumbing Code.

   4. Over Public Property. — Roof drainage water from a building shall not be permitted to flow over public property, except for Group A and J Occupancies.

5. Flashing. — Flashing and counterflashing shall be provided at the juncture of the roof and vertical surfaces.