(a) Accessible attics shall be insulated to achieve a minimum R-30 insulation value.
(b) Attic vents shall be modified as follows:
(1) Gable vents or vents that penetrate the roof surface shall be provided with noise control louver vents that meet the noise reduction levels shown in Table 15-A or transfer ducts that are at least six (6) feet in length. The ducts shall be of flexible insulated ducting with a bend so that there is no direct line-of-sight from the exterior through the duct into the attic.
(2) Eave vents do not require modification.
(c) Roofs with a slope of 2:12 or less and open beam ceilings shall be modified only if bearing walls are adequate to support the additional load stresses:
(1) Existing roof covering shall be removed to expose sheathing.
(2) Two (2) foot by six (6) foot rafters at twenty-four (24) inches on center shall be installed directly above the existing roof construction and supported by existing bearing walls, shall be insulated with R-19 fiberglass batts, and shall be covered with one-half (½) inch plywood sheathing.
(3) New roofing shall be installed on the new construction that can be adequately supported by the new framing and existing bearing walls.
(§ 2, Ord. 2616, eff. June 20, 1996)