24.321.309    VENTS

(1) Ventilation openings in vertical exterior walls, attics, foundations, or underfloor areas shall not exceed 144 square inches each. Attic ventilation openings shall not be located in soffits, eave overhangs, between rafters at eaves, or other overhang areas.

(a) Gable end and dormer vents shall be located at least ten feet from property lines.

(b) Underfloor ventilation openings shall be located as close to grade as practical.

(2) All such vents shall be covered with noncombustible corrosion-resistant mesh with openings not to exceed 1/4 inch or shall be designed and approved to prevent ember or flame penetration into the structure. Vents shall not be placed in walls that face heavy vegetative fuels.

(3) If a structure is not located in a designated WUI, this rule does not apply.

History: 50-60-901, MCA; IMP, 76-3-504, MCA; NEW, 2011 MAR p. 319, Eff. 2/25/11.