620 Olson Site Assessment & Remediation
Across the country, former industrial facilities are finding new life as they are repurposed for use as non-industrial commercial spaces such as retail spaces, churches, and in this case – a school. Often these buildings are brownfield properties whose past industrial use complicates redevelopment due to contaminated soil and water at the site.
Wenck was attained to complete a site assessment and redevelopment on a 30,000 square foot industrial building in South Minneapolis. The building was slated to change over to a charter school with an emphasis on teaching woodworking trade skills to students. Less than 45 days prior to the planned opening, an MPCA site assessment turned up a vapor problem that required timely mitigation for the building’s intended use.
The first step of any mitigation effort is a building diagnosis. Wenck put a uniform vacuum pressure field underneath the entire building using technology similar to residential radon mitigation. Utilizing the data from this assessment, our team customized a mitigation design based on the pressure fields we were able to put under the building. Soil conditions often vary from one part of the building to the next, and so design work must be nimble to adapt to the subsurface conditions.
Once the entire footprint of the building was mapped out, we switched into full-scale construction. Trenches were cut into concrete to allow the removal of some soil and the emplacement of perforated collection pipes and sump fans with a pea rock backfill. Then the concrete was patched, and piping was routed up to a centralized rooftop blower which draws vacuum across the building at low pressure from beneath the slab and vents it above the roofline so that it doesn’t enter the indoor air – ensuring air quality and safety.
Not only did the Wenck team identify the scope of the problem and complete the mitigation process in time for the school’s opening day, we secured $210,000 in grant funding from DEED and Hennepin County to do so – keeping cost efficiency, timeliness, and reliability top of mind.
Major Project features:
- Phase I, Phase II, Vapor Assessment
- Asbestos and Hazardous Material Survey
- Response Action Plan (RAP)
- Vapor mitigation design and oversight
- Construction Oversight for mitigation, UST removal and closures
- Grant Administration
- 68,000 sq ft slab on-grade
- 3,000 sq sub-grade boiler room
- 2 floor trenches running the length of the building
- Interior USTs (fuel oil, gasoline and fuel dispenser)
- Primarily PCE, TCE and breakdown compounds (>100X ISV)
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