Vermont

Statewide summary — confirm with your building department before designing

No value on this row was changed by this audit, but two of them are now confirmed against an adopted Vermont rule rather than left hanging, and the snow columns are filled from the state map. Vermont does publish a binding ground snow load map, which the earlier audit missed because it was looking for a residential code. The 2025 Vermont Fire and Building Safety Code deletes and replaces IBC Section 1608.2 with: "The map Ground Snow Loads for Vermont by Town or City from Annex VII of these rules shall be used in determining the minimum ground snow load. Ground snow loads above 2500 feet above sea level shall be approved by the AHJ and shall be based on an extreme value statistical analysis of data available in the vicinity of the site using a value with a 2-percent annual probability of being exceeded (50-year mean recurrence interval), or other means acceptable to the AHJ." The map itself is printed as Annex V, Minimum Ground Snow Loads for Vermont by Town or City. It has a four-value key and colours every town: 40, 50, 60 or 70 psf. Hence min 40 and max 70. The 40 psf band is confined to a few Champlain valley and southwest towns; 70 psf covers the Green Mountain spine, including Stowe, Mount Tabor, Stratton, Somerset, Glastenbury, Woodford, Killington and Chittenden. Above 2,500 feet the code refuses to give a number and requires a site-specific extreme value analysis approved by the AHJ, so 70 psf is the top of the mapped range and not the worst case in the state. Note that the amendment text says Annex VII while the annex is printed and indexed as Annex V; there is only one such map in the rules, so this is a numbering slip in the state document rather than a conflict. The stored 50 psf is the dominant band on that map and is retained as the representative figure, but it is one of four adopted values and is wrong by 20 psf in the mountain towns. Frost depth 60 inches is now confirmed rather than unverified. The same rules delete and replace IBC Section 1809.5 to require foundations to extend below the frost line of the locality "but not less than 5 feet below finished grade," or to be built to ASCE 32, or to be erected on solid rock. 60 inches is that state floor. Scope is the important caveat on this row. These rules apply to public buildings as defined by 20 V.S.A. Chapter 173, which takes in rentals, duplexes, condominiums, apartments, hotels, and commercial and institutional work, but not owner-occupied single-family dwellings. Vermont still has no statewide building code for owner-occupied one- and two-family homes, so there is no adopted Table R301.2 for that class of work and the IRC edition recorded on this row is not a state adoption. The code adopted here is the 2021 IBC. The seismic design category correction from B to C made by the earlier audit stands. Read at Site Class D and Risk Category II under the IRC single parameter method, the USGS ASCE 7-16 service returns short period design accelerations of 0.356 g at Burlington, 0.355 g at St Albans and 0.339 g at Essex Junction, all above the 0.33 g threshold and therefore category C, while Montpelier 0.260 g, Rutland 0.241 g, Brattleboro 0.206 g and Bennington 0.191 g read B. C is the northwestern Vermont governing case carried across the row. Termite risk none is correct. Wind speed 105 mph and winter design temperature -15 F remain unverified: the state rules contain no amendment to IBC Section 1609, so wind comes from the model code and its referenced ASCE 7 map, and no Vermont jurisdiction was found to have adopted the winter design temperature into a table of its own.