The following shall be used in Table No. R-202, Climatic and Geographic Design Criteria of the CABO One and Two Family Dwelling Code.
(a) Roof live loads.
Roof slope 3 in 12 or less: 20 psf
Roof slope over 3 in 12: 15 psf
Roof used as deck: 40 psf
(b) Roof snow load. The roof snow load shall be in accordance with section 7 of ASCE 7-88.
(c) Wind pressures. The minimum Design Wind Pressures (net pressures) set forth below apply to areas designated as experiencing basic wind speeds up to and including 80 mph, as shown in ASCE 7-88, Figure 1, Basic Wind Speed Map. These pressures also apply to buildings not over 30 ft. in height above finish grade, assuming exposure C or defined in ASCE 7-88.
(1) Minimum design wind pressure criteria.
(i) Buildings (for overturning racking or sliding); p = 20 psf.
(ii) Chimneys, p = 30 psf.
(iii) Exterior walls, p = 15 psf inward or outward. Local pressure at corners of walls shall be not less than p = 30 psf outward. These local pressures shall not be included with the design pressure when computing overall loads. The pressures shall be applied perpendicularly outward on strips of width equal to 10 percent of the least width of building.
(iv) Partitions, p = 10 psf.
(v) Windows, p = 20 psf inward or outward.
(vi) Roof, p = 20 psf inward or outward.
Roofs with slopes greater than 6 in 12 shall be designed to withstand pressures acting inward normal to the surface, equal to the design wind pressure for exterior walls. Overhanging eaves, cornices, and ridges, 40 psf upward normal to roof surface. These local pressures shall not be included with the design pressure when computing overall loads. The pressures shall be applied perpendicularly outward on strips of width equal to 10 percent of the least width of building. Net uplift on horizontal projection of roof shall not be less than 12 psf.
(2) Severe wind design pressures. If the construction is higher than 30 ft., or if it is located in an area experiencing wind speeds greater than 80 mph, higher design wind pressures than shown above are required. Use Section 6 of ASCE 7-88 for higher criteria and for determining where wind speeds greater than 80 mph occur. Pressures are assumed to act horizontally on the gross area of the vertical projection of the structure except as noted for roof design.
(d) Seismic conditions shall be in accordance with Section 9 of ASCE 7-88.
(e) Subject to damage from: weathering. A jurisdiction's weathering region shall be as established by the map in ASTM C 62-83.
(f) Subject to damage from: frost line depth. Exterior wall footings or foundation walls including those of accessory buildings shall extend a minimum of 6 in. below the finished grade and, where applicable, the prevailing frost line.
(g) Subject to damage from: termites. “Yes” shall be used in locations designated as Regions I, II or III. “No” shall be used in locations designated as Region IV. The map for Termite Infestation Probability in appendix A of CABO, One and Two Family Dwelling Code shall be used to determine the jurisdiction's region.
(h) Subject to damage from: decay. “Yes” shall be used in locations designated as moderate to severe and slight to moderate. “No” shall be used in locations designated as none to slight. The Decay Probability map in appendix A of CABO, One and Two Family Dwelling Code shall be used to determine the jurisdiction's decay designation.
(Approved by the Office of Management and Budget under control number 2502-0338)
[50 FR 39599, Sept. 27, 1985, as amended at 59 FR 36695, July 19, 1994]