Code of Massachusetts Regulations
780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS
Chapter 15 - Roof Assemblies and Rooftop Structures
Section 1504 - PERFORMANCE REQUIREMENTS
Subsection 1504.8 - Aggregate
Aggregate used as surfacing for roof coverings and aggregate, gravel or stone used as ballast shall not be used on the roof of a building located in a hurricane-prone region as defined in Section 1609.2, or on any other building with a mean roof height exceeding that permitted by Table 1504.8 based on the exposure category and basic wind speed at the site.
TABLE 1504.8 MAXIMUM ALLOWABLE MEAN ROOF HEIGHT PERMITTED FOR BUILDINGS WITH AGGREGATE ON THE ROOF IN AREAS OUTSIDE A HURRICANE-PRONE REGION
|
BASIC WIND SPEED FROM FIGURE 1609
(mph)b |
MAXIMUM MEAN ROOF HEIGHT (ft)a, c | ||
| Exposure category | |||
| B | C | D | |
| 85 | 170 | 60 | 30 |
| 90 | 110 | 35 | 15 |
| 95 | 75 | 20 | NP |
| 100 | 55 | 15 | NP |
| 105 | 40 | NP | NP |
| 110 | 30 | NP | NP |
| 115 | 20 | NP | NP |
| 120 | 15 | NP | NP |
| Greater than 120 | NP | NP | NP |
| For SI: 1 foot = 304.8 mm; 1 mile per hour = 0.447
m/s.
a. Mean roof height as defined in ASCE 7. b. For intermediate values of basic wind speed, the height associated with the next higher value of wind speed shall be used, or direct interpolation is permitted. c. NP = gravel and stone not permitted for any roof height. |
