Pennsylvania

Statewide summary — confirm with your building department before designing

This audit corrected the seismic design category from A to B. Checked against the USGS ASCE 7-16 design maps at Site Class D and Risk Category II, the short-period design acceleration at Philadelphia and in the Lehigh Valley around Allentown falls in the B band, so the stored A understated the requirement for the largest city in the Commonwealth. Pittsburgh, Erie, Harrisburg and Scranton all compute to A, so B is conservative for western and central Pennsylvania rather than wrong. Philadelphia sits fairly close to the A and B boundary and a site-specific determination is worth doing on any marginal project. Nothing else on this row was changed. Termite risk moderate encodes the moderate to heavy band of the IRC map, which is the right band for Pennsylvania. The 105 mph wind speed is an ultimate design wind speed at Risk Category II; Pennsylvania sits between mapped contours and a site read can land either side of it. The 30 psf ground snow load describes the southeast, and the northern tier and the Poconos are well above it. Frost depth and winter design temperature were not confirmed against an adopted Pennsylvania table. Under the Uniform Construction Code these values are set by the municipality enforcing the code, so confirm with your local code official. SNOW LOAD AUDIT, 2026. snow_load_min_psf and snow_load_max_psf are deliberately left null, and no value on this row was changed by this pass. Pennsylvania does not publish a ground snow load anywhere in the Uniform Construction Code. The Department of Labor and Industry adopts the 2021 International Residential Code at 34 Pa. Code section 403.21(a)(7), and the exceptions it takes to that code are about smoke alarm interconnection, stair treads and risers, stucco, attic venting and a list of energy provisions. None of them touch snow. The only place the UCC speaks to the snow figure at all is section 403.103(d), which reads in full: "A building code official shall determine the climatic and geographic design criteria contained in Table R301.2(1) of the 'International Residential Code of 2021' for residential construction." The Commonwealth therefore hands the number to the local code official and publishes no state table, no state map and no county list. There is no Pennsylvania analogue to Michigan's Table R301.2(5), and that absence, not a gap in searching, is why min and max are null. The delegation is weaker than it sounds, because Pennsylvania municipalities may elect not to administer and enforce the UCC. Section 403.103 is titled "Municipalities electing not to enforce the Uniform Construction Code," and in those municipalities residential plan review and inspection are performed by a certified third-party agency rather than by a municipal building department. So "the Pennsylvania ground snow load" is a fiction twice over: the Commonwealth has not set one, and in an opt-out municipality there is often no local government body that has set one either. The number that governs a given lot is whatever the reviewing code official has determined for it. On the commercial side the UCC adopts Chapters 2 through 10, 12 through 29 and 31 through 35 of the 2021 IBC, which includes Chapter 16 unamended, so ground snow load there routes to the ASCE 7 map. ASCE 7 is a private consensus standard, not a Pennsylvania government publication, and its mapped values were not treated as an official source for this audit. The Pennsylvania Housing Research Center at Penn State has published ground snow load work for the Commonwealth; the UCC does not adopt it by reference, it is not binding, and it was not used here. The 30 psf in ground_snow_load_psf is not drawn from any Pennsylvania-published document. It is a reasonable description of the southeast and it badly understates the northern tier and the Poconos, but it should be read as an unsourced placeholder rather than as a code requirement. Confirm the figure with the code official or third-party agency reviewing your permit.