780 CMR, ch. 34, pt. 1, 307, [BS] 503.9

Current through Register 1538, January 3, 2025

Subsection [BS] 503.9 - Bracing for unreinforced masonry parapets, chimneys, and appendages in major alterations

Where the work area exceeds 50 percent of the building area, and where the building is assigned to Seismic Design Category B, C, D, E or F, parapets constructed of unreinforced masonry, unreinforced masonry chimneys and exterior wall appendages shall be removed, have bracing installed, or anchored as needed to resist out-of-plane seismic forces, unless an evaluation demonstrates compliance of such items. Reduced seismic forces shall be permitted.

EXCEPTIONS:

1. If the height-to-thickness ratio of an unbraced unreinforced masonry parapet does not exceed 2.5, then bracing is not required. For the purpose of this exception the height shall be measured from either the level of tension anchors or the roof sheathing, whichever is lower.

2. Chimneys braced by or anchored to the roof structure and extending less than 4 feet above it.

780 CMR, ch. 34, pt. 1, 307, [BS] 503.9

Amended by Mass Register Issue 1532, eff. 10/11/2024.