Hydrovac Foundation Excavation Near Utilities
8-step process guide with equipment, safety, and cost information.
Foundation excavation using hydrovac is employed when new building, equipment, or structure foundations must be constructed in areas with dense underground utility infrastructure. Where mechanical excavation risks damaging buried pipes and cables, hydrovac provides the precision needed to excavate to exact foundation dimensions while protecting adjacent utilities.
This application is common in urban infill construction, industrial facility expansion, and utility structure installation. The hydrovac process allows contractors to work right up to the edge of existing utilities without damage, often eliminating the need for expensive utility relocations that would otherwise be required to create safe clearance for mechanical excavation.
Foundation excavation with hydrovac ranges from small equipment pads and sign post holes to large footing excavations for commercial buildings. The cost premium of hydrovac over mechanical excavation is typically offset by avoided utility relocation costs, reduced risk of utility strikes, and faster project completion.
Step-by-Step Process
Foundation Design Review
Review foundation plans, including dimensions, depth, and bearing requirements. Identify all utilities within and adjacent to the excavation footprint.
Utility Verification
Pothole to verify exact positions of all utilities near the foundation. Determine which utilities need protection in place versus relocation.
Excavation Layout
Stake the foundation excavation boundaries and establish grade control points. Mark utility protection zones within the excavation.
Hydrovac Excavation
Excavate to foundation depth using hydrovac. Maintain precise wall lines and grade. Use reduced pressure near utility crossings.
Utility Protection
Install protection for any utilities that pass through or near the foundation excavation, including pipe supports, concrete encasement, or sleeves as required.
Foundation Preparation
Prepare the excavation bottom for foundation construction including proof rolling, compaction testing, and placement of granular base material as specified.
Foundation Construction
Install formwork, reinforcing steel, and cast concrete for the foundation. Coordinate utility protection with structural elements.
Backfill
After foundation curing, backfill around the structure with specified material, compacting in lifts to prevent settlement.
Equipment Recommendations
- Large hydrovac truck for volume excavation
- Multiple nozzle types for different soil conditions within the excavation
- Grade control equipment (laser, transit) for precise depth control
- Shoring equipment for deep excavations
- Dewatering capability if groundwater is present
Safety Considerations
- ⚠Verify all utility locations before and during excavation
- ⚠Follow OSHA excavation standards for shoring and access
- ⚠Implement fall protection at excavation edges
- ⚠Monitor excavation walls for signs of instability
- ⚠Coordinate with structural engineer on utility protection requirements
Cost Factors
- ●Volume of material to be excavated
- ●Depth of foundation below grade
- ●Number and complexity of utility crossings within the excavation
- ●Shoring and dewatering requirements
- ●Disposal costs for excavated material
- ●Foundation material and labor costs (separate from hydrovac)
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