How Push Piers Work
Push piers are steel pipe sections, typically 2.875” or 3.5” outside diameter, installed by driving them sequentially deeper into the ground. A hydraulic ram is positioned over the footing, and pier sections are added as the drive advances.
Unlike helical piers (which screw in), push piers have no helical plates - they are driven purely by hydraulic force pushing against the structure’s dead load. When resistance equals the specified load, the pier is at refusal and installation stops.
A bracket welded to the last pier section is attached to the footing. When all piers at a given location are installed, hydraulic jacks simultaneously lift the structure.
Installation Process
- Excavate access trench at each pier location - typically 18-24” wide, 12-18” deep, to expose the footing.
- Position drive stand over the footing. The stand transfers hydraulic force from the ram through the pier to the soil.
- Drive pier sections - 3-4 foot pipe sections are added as the drive progresses. Each section is driven until the next is required.
- Drive to refusal - when hydraulic pressure reaches the specified proof load (typically 1.5-2x the design load), the pier is at capacity depth.
- Install bracket - a foundation bracket is attached to the footing and welded or pinned to the pier shaft.
- Lift - all installed piers are loaded simultaneously with hydraulic jacks. A laser level monitors grade during lift.
- Lock-off - hydraulic pressure is maintained while steel shims are placed under the bracket to lock the load transfer. Jacks are released.
- Backfill - trenches are backfilled and compacted. Concrete patching where needed.
Push Piers vs. Helical Piers: Decision Guide
| Factor | Push Piers | Helical Piers |
|---|---|---|
| Cost per pier | Lower ($1,000-$3,000) | Higher ($1,200-$3,500) |
| Perimeter perimeter work | Excellent | Good |
| Interior slab use | Limited | Good (with coring) |
| Light structures | Not recommended | Yes |
| Crawlspace use | Limited by clearance | Good |
| Tension applications | No | Yes |
| Vibration during install | Moderate | Low |
| Installation speed | Fast | Moderate |
For most residential perimeter underpinning projects on homes with conventional framed or masonry exteriors, push piers are the cost-effective and technically appropriate choice. When interior piers are needed or the structure is lighter, helical piers are typically specified.
Cost Factors
The per-pier cost of push piers ($1,000-$3,000) is affected by:
- Depth to refusal - more pier sections needed for deeper installations
- Perimeter access - landscaping, hardscaping, fencing, or utilities near the foundation increase labor
- Bracket type - varies by foundation configuration (footing shape, slab edge vs. stem wall)
- Local labor market - significant regional variation in foundation contractor rates
A typical residential project requiring 8 push piers costs $8,000-$18,000, including all materials, installation, lift, and site cleanup.