Calculate cubic yards, bags, and SLC-accurate Utah ready-mix costs for driveways, seismic foundations, patios, retaining walls & more — SLC Building Services permit, Utah contractor license, Wasatch Fault SDC D/E, 30-inch frost, Lake Bonneville soils.
Enter dimensions to calculate volume, bags needed, and SLC Utah ready-mix material cost.
Driveway: 4–5 in., 3,500 PSI min (SLC freeze-thaw), air-entrained, #4 rebar at 16 in. OC, 6 in. compacted gravel base. SLC Building Services permit — (801) 535-6000. Utah DOPL contractor license required. 30 in. frost. Seismic hooks per IBC SDC D. ACI 306 Nov–Mar; ACI 305 May–Sep.
Sidewalk 4 in · Driveway 5 in · Pool Deck 4–5 in · Slab 5 in · Foundation 6 in · Footing 12–24 in (min 30 in. frost depth)
Salt Lake City sits at the crossroads of two of the most challenging concrete environments in the American West — a major seismic fault zone and a severe mountain climate with a 30-inch frost depth. The Wasatch Fault runs directly through the Salt Lake Valley; combined with soft Lake Bonneville lacustrine soils that are highly susceptible to earthquake-induced liquefaction, SLC has some of the most complex foundation engineering requirements of any city its size in the US. All structural concrete, foundations, and retaining walls require a Utah-licensed Structural or Professional Engineer and special inspection. Permits and inspections through SLC Building Services Division — (801) 535-6000.
All exterior flatwork: 3,500 PSI min, air-entrainment 5–7% (W/C ≤ 0.45) for freeze-thaw durability — 3,000 PSI is NOT adequate for SLC exterior · Seismic structural / foundation: 4,000 PSI min, Utah-licensed SE/PE design, SDC D seismic hooks, special inspection during pour and rebar placement · Frost depth: 30 in. min for all SLC footings — below the frost line, confirmed via SLC Building Services · Geotechnical/soils report: required for all structural work — SLC Building Services requires soils report if site conditions warrant; mandatory on Lake Bonneville deposits for liquefaction assessment · ACI 306 (Nov–Mar): insulated blankets, heated enclosures, minimum 50°F concrete temperature at placement; maintain 50°F for 7 days; never pour on frozen subgrade · ACI 305 (May–Sep above 90°F): air-entrained mixes + cool curing water + wet burlap cure · Utah DOPL contractor license: all contractors must hold current Utah DOPL Residential or General Contractor license before pulling any SLC permit.
The Wasatch Fault is one of the most hazardous urban faults in the United States. Running directly through the densely populated Wasatch Front — including Salt Lake City, Provo, and Ogden — it is capable of generating a magnitude 7.0–7.5 earthquake. USGS estimates a 43% probability of a M6.75+ earthquake in the next 50 years. Most of the Salt Lake Valley is classified as Seismic Design Category D or E under the IBC, requiring full seismic structural design by a Utah-licensed Structural Engineer (SE). Requirements include: seismic hooks (135°) on all structural ties; ASTM A706 or specially certified A615 rebar; continuous special inspection during rebar placement and concrete pours; and a geotechnical report assessing liquefaction risk. Near the Wasatch Fault trace, a site-specific fault investigation by the Utah Geological Survey must be submitted before building permits are issued.
Salt Lake City's mountain climate brings hard winters with average lows of 20–28°F in December–February and recorded lows near 0°F. The 30-inch frost depth — one of the deepest in any major western US city — means all footings must extend at least 30 inches below grade. During cold-weather pours (November through March), ACI 306 practices are mandatory: maintain concrete at minimum 50°F at placement; use Type III (high-early-strength) or Type I/II with calcium chloride accelerator; wrap all fresh concrete in insulating blankets rated for the forecast low; never pour on frozen subgrade or forms; protect poured concrete from freezing for a minimum of 7 days. Air-entrained concrete (5–7%) is mandatory for all exterior SLC concrete — it provides both freeze-thaw durability and some cold-weather protection. SLC winters average 56 in. of snowfall annually.
Much of the Salt Lake Valley sits atop ancient Lake Bonneville lacustrine deposits — soft clays, silts, and fine sands left by the prehistoric lake that once covered the Great Basin. These soils are soft and compressible under static loads, requiring careful foundation design. More critically, saturated Lake Bonneville silts and fine sands are highly susceptible to earthquake liquefaction — during a major Wasatch Fault event, these soils can temporarily behave like a liquid, causing rapid and catastrophic foundation settlement. USGS liquefaction hazard maps show large portions of the SLC valley at moderate-to-high liquefaction risk. For any structural project on Lake Bonneville deposits, a full geotechnical/soils report is required by SLC Building Services — the geotech will assess liquefaction risk and may require deep footings, driven piles, ground densification, or other mitigation. All geotech work must be performed by a Utah-licensed geotechnical engineer.
Never proceed with a structural concrete foundation in Salt Lake City without a geotechnical/soils report from a Utah-licensed geotechnical engineer. SLC Building Services requires a soils report for all structural projects where site conditions warrant, and this is virtually all work on Lake Bonneville deposits. The geotech report will determine: bearing capacity; liquefaction risk and required mitigation; frost protection requirements; whether standard footings, deep piers, or ground improvement are needed; and any Wasatch Fault setback requirements. Projects near the Wasatch Fault trace require a separate fault investigation report per Utah Geological Survey standards. For seismic structural design, your engineer must be a Utah-licensed Structural Engineer (SE) — a Professional Engineer (PE) alone is not sufficient for SDC D/E seismic structural design in Utah. Contact SLC Building Services at (801) 535-6000.
Fresh concrete that freezes before reaching 500 PSI strength is permanently damaged — ice crystal formation destroys the cement-aggregate bond and no amount of later warming will restore full strength. In SLC's cold winters (November–March), never pour without a verified warming and protection plan: check forecast for 72 hours; if any period below 35°F is expected, use heated enclosures or insulated blankets rated for the forecast low; order Type III cement or calcium chloride accelerator to accelerate strength gain; maintain concrete at ≥ 50°F for 7 days minimum; and never pour on frozen subgrade — thaw ground completely before forming. Air-entrainment (5–7%) is mandatory in all SLC exterior concrete regardless of season — it provides essential freeze-thaw cycle durability year-round. Contact SLC Building Services (801) 535-6000 for permit requirements.
| Mix / PSI | SLC UT Price / Cu Yd | National Avg | Best For | SLC Spec | Utah Code |
|---|---|---|---|---|---|
| 3,000 PSI | $130–$140 | $143–$158 | Interior slabs only — NOT exterior | NOT for SLC Exterior | Interior Only |
| 3,500 PSI Air-Entrained — SLC Standard Exterior | $135–$147 | $153–$166 | Driveways, sidewalks, patios, pool decks | 5–7% Air · W/C ≤ 0.45 | Compliant |
| 4,000 PSI — Seismic Foundation / Structural | $142–$157 | $161–$173 | Seismic foundations, grade beams (UT SE req.) | UT SE + Special Inspection | Compliant |
| 4,500 PSI — Commercial Seismic | $151–$166 | $171–$181 | Commercial seismic structural | UT SE + Inspection | Compliant |
| 5,000 PSI — High Strength | $161–$178 | $178–$193 | Tilt-up / industrial / seismic high-load | Engineer Spec | Compliant |
| ACI 306 Winter Add-Ons (Nov–Mar) | +$8–$18/yd | +$8–$18/yd | All SLC pours below 40°F | ACI 306 Required | Best Practice |
(1) Always specify 3,500 PSI air-entrained (5–7%) for ALL exterior SLC concrete — never 3,000 PSI outside; freeze-thaw cycles will destroy non-air-entrained exterior slabs within 3–5 years; (2) Geotech / soils report from Utah-licensed geotech before any structural pour — Lake Bonneville liquefaction and soft-soil bearing assessment is essential; (3) Utah-licensed Structural Engineer (SE) for all seismic / structural design — SDC D/E design requires SE, not just PE; (4) ACI 306 cold-weather plan for Nov–Mar — insulated blankets, heated enclosures, Type III cement; and (5) Silane/siloxane sealer at 28 days for all exterior slabs — protects against SLC road de-icing salts and freeze-thaw. Permits at SLC Building Services (801) 535-6000 · Utah DOPL license at dopl.utah.gov.
| Project | Dimensions | Cu Yards | 80 lb Bags | Recommendation |
|---|---|---|---|---|
| Small Patio | 10×12 ft × 4 in. | 1.48 yd | 67 bags | Bags OK / 3,500 PSI air-entrained only |
| Standard Driveway (SLC) | 16×22 ft × 5 in. | 5.43 yd | 245 bags | Ready-Mix · 3,500 PSI Air-Entrained |
| Garage / Rear Slab | 20×22 ft × 5 in. | 6.79 yd | 306 bags | Ready-Mix · 3,500 PSI Air-Entrained |
| Pool Deck | 20×30 ft × 4 in. | 7.41 yd | 334 bags | Ready-Mix · 3,500 PSI Air-Entrained |
| Seismic Foundation | 30×50 ft × 6 in. | 27.78 yd | 1,250 bags | Ready-Mix · 4,000 PSI · UT SE + Special Insp. |
| Deep Footing (30 in. frost) | 12 in. dia × 36 in. | 0.13 yd | 6 bags | Bags OK / 3,500 PSI air-entrained |
Official references for Salt Lake City, Utah concrete projects
Apply for building permits, schedule concrete inspections (footing, foundation, slab, special inspection), and submit seismic structural plans through the SLC Building Services Division — (801) 535-6000. SLC requires Utah DOPL contractor license before pulling any permit. Structural permits require Utah SE stamped drawings, seismic design calculations, and soils/geotech report where required. Near the Wasatch Fault trace, a Utah Geological Survey fault investigation report is required before permit issuance.
Visit SLC Building ServicesAll contractors performing concrete and construction work in Salt Lake City must hold a current Utah Division of Occupational and Professional Licensing (DOPL) contractor license. Verify any contractor's Utah license at dopl.utah.gov before hiring. For seismic structural and foundation design, your engineer must be a Utah-licensed Structural Engineer (SE) — a PE alone is not sufficient for SDC D/E seismic design in Utah. Verify Utah SE license at the Utah SE licensing board via DOPL. Always check license status is active and in good standing before signing contracts.
Verify Utah DOPL LicenseAccess Utah Geological Survey fault investigation maps, liquefaction hazard maps, and seismic ground-shaking data for Salt Lake City. UGS publishes the official Wasatch Fault zone maps used by SLC Building Services for determining fault investigation requirements. Use UGS interactive maps to check if your parcel is within the Wasatch Fault Surface Rupture Hazard Zone — if so, a site-specific fault investigation by a qualified geologist is required before SLC will issue building permits. Also access Lake Bonneville soil maps and liquefaction susceptibility data for foundation planning.
View UGS Wasatch Fault Maps