CITY OF SAUK RAPIDS

ROOF VENTS

 

 

 

 

SECTION R806 ROOF VENTILATION

 

  1. R806.1 Ventilation required.  Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow.

 

  1. R806.2 Minimum area.  The total net free ventilating area shall not be less than 1 to 150 of the area of the space ventilated except that the total area is permitted to be reduced to 1 to 300, provided at least 50 percent and not more than 80 percent of the required ventilating area is provided by ventilators located in the upper portion of the space to be ventilated at last 3 feet (914 mm) above eave or cornice vents with the balance of the required ventilation provided by eave or cornice vents.  As an alternative, the net free cross-ventilation area may be reduced to 1 to 300 when a vapor barrier having a transmission rate not exceeding 1 perm (57.4 mg/s.m2.Pa) is installed on the warm side of the ceiling.

 

  1. R806.3 Vent clearance.  Where eave or cornice vents are installed, insulation shall not block the free flow of air.  A minimum of a 1-inch (25.4 mm) space shall be provided between the insulation and the roof sheathing at the location of the vent.

 

 

Note

Ridge vents and gable louvered vents are an acceptable alternative.

 

Any garage with an enclosed attic space will also need to be ventilated.