By Andy Kroneberger
Renovation Division Manager, Sun Country Builders
In my nearly ten-year construction management career, I’ve had my share of challenging jobs, but I’d never experienced anything like the first time I visited my latest renovation project. After taking two steps into a ground floor unit that day, I felt off balance – like I’d developed a sudden case of vertigo. This building had begun to sink and was already approximately eight inches out of level.
The building was one of two at San Martin de Porres apartments in Spring Valley with significant structural integrity problems that required lifting and stabilization. The project’s affordable housing developer, MAAC – who Sun Country Builders has partnered with on several previous renovations – entrusted us to restore the property and make it safe and livable again for residents.
Sun Country Builders has performed renovations for more than 40 years, working on more than 3,500 units with more projects currently underway. This project was still a significant undertaking, as we had not completed a renovation that involved this level of structural repairs. Something had to be done and fast. With this type of work, collaboration is key. We enlisted teams from the structural engineers Helfrich-Associates, our expert foundation repair subcontractor Eagle Lift and MAAC’s development team including project manager Rachel Loader, to ensure we got off to a successful start to stabilize the building.
Meeting Each Challenge Together
The partial failure of a retaining wall behind the two buildings was the main cause of the structural instability. We set out to secure the buildings first, and lifting the building was a multi-step process. First, we removed all materials from the interior of the building including cabinets, flooring and shower. Next, ground penetrating radar was used to locate post-tension cabling. Then, our subcontractor worked to demolish the existing concrete slab and excavate two feet beyond the bottom of those footings which were four and a half feet deep in some locations.
As anyone in construction industry knows, we are at the mercy of the weather. Just weeks into the renovation, heavy rain delayed our progress. Altogether, almost eleven inches of rain fell during the months of January, February and March making work on the outside of the buildings impossible for most of that time. But with commitments from the entire project team – SCB, MAAC, and especially our subcontractors – we mitigated most of the time lost from the weather delays.
The original plan for the stabilization called for 135 individual piles to be installed through the buildings’ slabs and driven up to 25 feet onto the bedrock below. Due to larger than anticipated concrete footings and the weight of the structures, 72 additional piles were ultimately required and 207 total piles had to be driven deeper than originally estimated – some to depths of almost 50 feet (about the width of a basketball court!). SCB Project Superintendents Jay Stehlik and Adam Henderson’s oversight during this process and throughout the project was crucial.
During the process of installing the piers on the side of the building adjacent to the failing retaining wall, an upper portion of the wall displaced an additional six inches making it unsafe to continue the work in the buildings. Eagle Lift needed to temporarily shift their focus to repairing the wall.
Once it was safe to resume work on the building, Eagle Lift brought in a hydraulic jacking system. The painstaking process of lifting the two buildings required the work of several specialized crew members totaling almost 6,500 man hours. Once lifting was complete, a high-strength expansive polymer grout was injected to fill the void and stabilize the soil under the affected buildings. The day the onsite team received the data that the stabilization had worked was a huge milestone for all of us.
Collaboration Start to Finish
The innovative solutions implemented at San Martin de Porres and the success of this project is a testament to SCB’s preconstruction collaboration with the client and the design team and, in this unique circumstance, specialized foundation repair contractors who provided insight on design and construction concerns. We were also able to revitalize the property with extensive interior and exterior renovations to 116 units. We replaced a total of 60 feet of retaining wall, repaired or replaced over 1,000 feet of steel tube fencing and gates and transformed the property with landscaping improvements. Our work created lasting value for residents and stakeholders.
Our achievement at San Martin de Porres stands as a benchmark for executing complex rehabilitation construction projects with precision and excellence. As SCB project manager Kim Nichols said, “Our success was due to clear detailed communication. The renovation evolved into multiple side projects where repairs were needed in various areas. Having MAAC project manager, Rachel Loader, the architect, Joe Martinez and our entire SCB project team collectively pursue all options allowed us to meet project milestones.”
Loader, who has worked with us on three projects, said this about our successful collaboration on San Martin de Porres: “Every project comes with its own trials and tribulations. However, the SCB team and I have always been able to work through them and exceed our goals. Due to unusually high rains, footing depths that were not expected, and other supply issues, we hit delay after delay. I truly appreciate everyone’s hard work and dedication to not only finish on time with all the additional requests but do it with a smile and such professionalism.”
Ultimately, construction was completed in 11 months. I often tell people that the best part of my job as renovation division manager is seeing our work’s impact on residents. Displaced residents moved back in just in time to celebrate Christmas in their homes. The gratification of seeing folks enjoy the holiday season safely at San Martin de Porres cannot be understated. This reaction fuels Sun Country Builder’s passion to support our clients – like MAAC – in achieving their mission.