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GROSS AREA OF OPAQUE ROOF SURFACES. Gross area of <br />opaque roof surfaces means the total surface of the roof assembly exposed <br />to outside air or unconditioned spaces. The opaque roof assembly shall <br />exclude skylight surfaces, service openings, and overhangs. <br />NET FREE VENT AREA. Net free vent area means the total area <br />through which air can pass in a screen, grille face or register. <br />ROOF AREA. Roof area means attic floor area; or, if there is no attic, <br />"roof area" means the horizontal projection of a roof area measured from <br />the outside surface of the exterior wall. <br />402.1.1.3 Construction Documents. Plans shall be submitted which <br />indicate insulation type, thickness, and location; ventilation opening types, <br />sizes and locations; radiant barrier location; and roof surface type as <br />appropriate, depending on the option selected from Table 402.1.1.1 <br />402.1.1.4 Roof insulation. Roof insulation for unconditioned habitable <br />spaces shall be provided as follows: <br />1. In buildings with an attic space provide either: <br />1.1 R -30 insulation installed above the ceiling level, or <br />1.2 R -19 insulation installed at the roof level between <br />the roof framing members. <br />2. In buildings without an attic space provide either: <br />2.1 R -19 insulation installed at the roof level between <br />the roof framing members, or <br />2.2 R -15 entirely above the roof deck. <br />402.1.1.5 Ventilation. Ventilation shall be provided by at least one of the <br />following: <br />1. A baffled ridge vent installed in accordance with <br />manufacturer's instructions in addition to lower inlet <br />openings to provide a total of no less than one (1) square <br />foot of net free vent area for each 300 square feet of roof <br />area. No less than 30 percent of the total vent area shall be <br />in either the ridge vent or the lower half of the ventilated <br />space. <br />2. A solar- powered exhaust fan that provides at least one (1) <br />cubic foot per minute of airflow for each square foot of <br />roof area. <br />3. Upper and lower vents with total net free vent area of at <br />least one (1) square foot for each 150 square feet of roof <br />area. At least 30 percent of the total vent area shall be in the <br />upper of the ventilated space and at least 30 percent of the <br />5 <br />