By Philip Kedrowski Redleaf Consulting

In the last issue, I discussed why building permits aren’t required for residential construction in the Big Sky area. Although a building construction permit isn’t applicable, a land use permit from the Gallatin County Planning Department is required. To obtain this permit, a geotechnical evaluation is usually necessary in mountainous areas.
Section 32.2 of the planning department’s zoning regulations requires a geotechnical investigation if any portion of the property is greater than 15 percent (15-foot rise in 100-foot run) slope and/or within 100 vertical feet of any prominent ridgeline.
Since this requirement only applies to the conditions outlined in Section 32.2, many people believe geotechnical evaluations aren’t necessary for projects on flat terrain. However, this isn’t exactly true.
Montana has adopted the International Building Code. Section 1803.5.11 of the IBC requires a geotechnical investigation for structures within seismic design categories C, D, E, and F. The entire Big Sky area is seismic category D. Therefore all structures being constructed in Big Sky must have a geotechnical evaluation performed in order to meet the adopted code.
Codes and regulations aside, it makes sense to have a geotechnical evaluation performed if you are thinking of building in Big Sky. The cost is typically between $2,500 and $5,000. To put this into perspective, the median home value in Big Sky is $749,000, according to real estate firm ERA Landmark. Therefore, the cost of a $5,000 geotechnical evaluation is 0.7 percent of the median home value.
That’s a bargain for the peace of mind you’ll have knowing that your home is built on solid ground. In addition, a good geotechnical analysis often provides foundation recommendations that can save thousands of dollars in construction expenses.
Smart land buyers in Big Sky procure a geotechnical analysis as part of their due diligence during the land purchase process.

Philip Kedrowski is owner/engineer of Redleaf Consulting, PLLC. Redleaf is the only engineering company based in Big Sky.