Replace unreinforced masonry chimneys with lightweight metal flue chimneys in seismic areas
FEMA P-2325 §FEMA Mitigation Recommendations (Earthquake)Description
Masonry chimneys built before the late 1960s typically lack reinforcing and are subject to collapse in earthquakes — through the roof, into living space, or onto the structure below. In high-seismic areas, replace with engineered reinforced masonry or a lightweight metal flue chimney enclosed in non-bearing framing.
Why this exists
Collapsing masonry chimneys are a documented life-safety hazard in residential seismic events. Lightweight flue chimneys eliminate the falling-mass risk while preserving the heating-appliance vent function.
Categories
Source
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Continuous load path from roof to foundation · HUD RSDG §2.4
- Residential structural reliability targets 1-in-100 to 1-in-1000 annual probability of failure · HUD RSDG §2.5
- Residential floor live load: 40 psf minimum (30 psf sleeping rooms) · HUD RSDG §3.4
- Wind load design uses ASCE 7 basic wind speed for the locality · HUD RSDG §3.6
- Ground snow load for Virginia: 25 psf eastern, up to 40 psf western mountains · HUD RSDG §3.7
Last reviewed 2026-05-11.