How The Dwyer Company Stabilized Mason Fire Annex with Precision Underpinning and Shoring Solutions

When Mason Fire Annex required new staircases so the lower level of the Mason Fire Annex could connect to the upper level of the structure, the project presented a unique engineering challenge: excavation near an existing building, if not properly addressed the building would settle and slope. In close collaboration with Haglage Construction, Inc., The Dwyer Company installed push piers to support the existing building when excavating and provided a wood lagging solution attached to the new push piers to prevent soils from being undermined from underneath the footer. Because the soil conditions were both sandy and water logged we also used sump pumps to remove excess water and used smaller excavation cuts to limit the amount of soil exposure to the water and sandy conditions, proving that even the tightest access points, poorest soil conditions and structural lacking projects can achieve structural integrity with the right expertise and approach.

Quick Facts

The Challenge:

The primary challenge was excavating 6 feet below the existing footer elevation for staircase installation while maintaining structural integrity of the Mason Fire Annex building. The project required our team to carefully navigate sandy, waterlogged soil conditions and establish stable working conditions in a confined 10-foot wide section. Conventional excavation couldn’t achieve the required depth without extensive and costly temporary shoring systems—and risked significant settlement or structural failure given the poor soil bearing capacity and constant groundwater infiltration.

The Solution: Integrated Push Pier and Wood Lagging System

The Dwyer Company designed and installed a push pier underpinning system that transferred building loads to stable soil strata below the excavation zone. The solution required detailed pre-installation planning, precise pier spacing calculations, and careful coordination with active excavation operations.

The installation process involved establishing load-bearing push piers adjacent to existing footers, executing controlled excavation to 6-foot depths below footer elevation, and implementing wood lagging panels attached directly to the pier system to retain soil and prevent undermining. To manage groundwater and sandy conditions, we deployed continuous sump pumping and utilized smaller excavation cuts to minimize soil exposure and maintain stability throughout the operation.

The entire installation maintained the project’s aggressive construction timeline, providing Mason Fire Annex with a permanently stabilized foundation system and eliminating the risk of structural settlement or soil undermining during and after construction.

Key Project Details

Underpinning Scope

wide structural support section requiring full foundation transfer

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Excavation Depth

below existing footer elevation in challenging soil conditions

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Load Transfer System

Push pier array engineered to support building loads during and after excavation

Soil Retention

Custom wood lagging solution integrated with pier system to prevent undermining

Groundwater Management

Continuous sump pumping with staged excavation to control sandy, saturated conditions

Project Coordination

Seamless collaboration with Haglage Construction to maintain construction schedule

Why Push Piers?

Push pier systems are essential for commercial properties experiencing foundation issues that threaten structural safety, operational continuity, or property value. Common scenarios include:

The Impact: On-Time Delivery with Zero Structural Compromise

Cost-Effective Solution

The integrated push pier and wood lagging system eliminated expensive temporary shoring structures and reduced engineering complexity, delivering budget optimization without compromising structural performance.

Schedule Preservation

Completing the underpinning and excavation work within the construction timeline prevented delays that would have cascaded through subsequent construction phases.

Zero Structural Settlement

Most critically, the system achieved zero structural settlement in challenging soil conditions, providing Mason Fire Annex with permanent foundation stability for their new staircase structure—even in sandy, waterlogged conditions where conventional methods would have failed.

Why Choose The Dwyer Company for Structural Integrity?

Deep History • Solid Choice

The Dwyer Company’s proven track record in commercial and industrial foundation systems made us the trusted partner for this critical infrastructure project. Our team’s technical expertise, advanced equipment, and commitment to precision execution delivered a foundation system that will support decades of heavy industrial use.

Call The Dwyer Company and one of our experts will get you taken care of with an accurate inspection quote!

Call The Dwyer Company and one of our experts will get you taken care of with an accurate inspection quote!