IDAHO · ADA COUNTY
Boise Wind Load Requirements
Moderate inland-valley wind in the Treasure Valley, with foothills terrain that can drive localized topographic effects under ASCE 7-22.
TREASURE VALLEY · TERRAIN
Wind & Exposure Context
Boise sees moderate inland-valley wind, but the Boise Foothills add terrain effects that flat-map speeds alone can miss.
Valley Channeling
The Boise River corridor and broader Treasure Valley funnel regional winds along a preferential NW–SE axis.
DIRECTIONALFoothills Downslope
The Boise Front rises just north and east, producing downslope and drainage winds that locally enhance speeds.
TERRAINExposure B
Central, North End, East and Southeast Boise plus established suburbs generally qualify as Exposure B per ASCE 7 §26.7.
URBAN/SUBURBANTopographic Kzt
Hillside, ridge and escarpment sites near the foothills may carry Kzt above 1.0 near crests, returning toward 1.0 away from the feature.
SITE-SPECIFICSpecial wind regions are possible where foothills terrain steepens — slopes, ridges and Bogus Basin Road–corridor sites can amplify pressures and warrant site-specific review. Valley floors typically remain Kzt = 1.0.
ADA COUNTY · COMPLIANCE
What You Need to Comply
The inputs and authorities a Boise permit submission has to satisfy under IBC with Idaho amendments.
Design Wind Speed
Risk Category II ranges 90–100 mph (3-sec gust); higher Risk Categories read a higher-MRI map. Verify the value for your exact site.
90–100 MPHCode & Edition
IBC with Idaho state amendments referencing ASCE 7-22. Idaho can lag editions 1–3 years — confirm the adopted edition.
IBC · ASCE 7-22Exposure Category
Determine Exposure B vs. C from surrounding roughness; foothills and open Snake River Plain edges shift the call.
PER §26.7Topographic Factor
Run a Kzt analysis for hills, ridges and escarpments per ASCE 7-22 §26.8 — don't assume Kzt = 1.0 on foothill slopes.
§26.8 KztPE Sealing
Commercial, multi-family and engineered/foothill designs need Idaho-licensed PE-sealed calculations via IPELS.
PE REQUIREDPermit Authority
City of Boise Planning & Development Services in city limits; Ada County Building Department for unincorporated areas.
CITY / COUNTYIDAHO · OFFICIAL RESOURCES
Authorities & Statewide References
Official Ada County and Idaho sources, plus statewide wind-load context.
City of Boise PDS
Planning & Development Services — permits and requirements.
OFFICIALIdaho PE Board (IPELS)
Licensure of Professional Engineers & Land Surveyors.
OFFICIALIdaho Div. of Building Safety
Statewide building code adoption and enforcement.
OFFICIALAll State Requirements
Browse wind-load requirements for every state.
PARENT HUBWind Speed by Location
Look up design wind speeds across the country.
MAP TOOLWind Load Calculators
Run Boise-specific ASCE 7-22 calculations and PE-ready reports.
CALCULATEASCE 7-22 · BOISE-READY
Automate Your Boise Wind Loads
Enter a Boise address or zip and get the 90–100 mph velocity range, Exposure B, topographic guidance for foothill sites and PE-ready reports.