Lubbock, TX Hurricane Preparedness: Roof Standards (2026)

Section 28.09.131 lists the local amendments the city made when it adopted the International Building Code, and item (24) rewrites Section 1607.1 to add Table L1607, Summary of Climatic and Geographic Design Criteria, which sets the numbers Lubbock's structural engineers and roofers have to design to. The table sets an ultimate design wind speed that climbs with the building's risk category: 100 mph (77.5 mph allowable stress design) for Risk Category I structures like agricultural buildings, 107 mph (83 mph ASD) for Risk Category II, the standard for most homes and commercial buildings, 113 mph (88 mph ASD) for Risk Category III, and 118 mph (91.5 mph ASD) for Risk Category IV structures such as hospitals and emergency facilities.

Roofs also have to carry a 15 psf ground snow load. The same table sets the seismic design category at A, meaning seismic loads rarely control a Lubbock roof design, alongside a 12-inch frost line depth, moderate weathering exposure, and a 100-year hourly rainfall rate of 3.3 inches per hour that feeds into the roof drainage and scupper design required elsewhere in the same amendment package. A separate amendment in the same section, item (25), lets roof live loads be reduced for design purposes, but bars any reduction on roof slopes of four inches per foot or less, or on an arch or dome with a rise under one-eighth of its span, keeping shallow-slope roofs, the kind most exposed to ponding and wind uplift, at their full design load.