20045_Powers Site_SIR_20220406

DWM Brownfields Inspection Report
Submitted By: jkslaughter_ncdenr
Submitted Time: 04/07/2022 10:14 AM

I. Inspection Information
Date & Time: 04/06/2022 10:28 AM Inspection Type: Meeting

Brownfields Staff:
Kevin Slaughter
Other Personnel:
Alexis McKenzie - Hart & Hickman, David
Walker - SCS Engineers, Liquid boot/VIMS
installer, and construction superintendents.
Location:
Lat: 35.211565106105965, Long: -80.8700209478824,

Brownfields Inspection Report: Powers Site (RN), 20045-16-060
04/06/2022 10:28 AM
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II. Project Information
Number: 20045-16-060 Name: Powers Site (RN)
Address: 436 W. Tremont
Avenue

City: Charlotte

County: Mecklenburg

III. Environmental

Current Use of Property: Residential
Structures on Property: New Structures Violation: No

Vapor Mitigation Systems: Observed Vapor Mitigation Violation: Yes

Use of Surface Water or Groundwater: Not Observed Water Use Violation: No

Exposed Soils: Observed Exposed Soils Violation: No
Summary: The solid PVC piping, VaporVent, sub-slab monitoring points, VIMS riser and
hollow stake issues that could be observed during the site inspection appeared to have
been addressed (Photos 1-3). The Liquid Boot VIMS barrier has been installed since the
previous Inspection, so not everything that was repaired was visible at the time of the
inspection. It did appear based on the path of the exposed piping, location of solid PVC
bridging thickened slab trenches, relocated and plumbed riser and solid conduit stakes,
that all the sub-slab components had been installed per the VIMS Design. See Use of
Basements and Inspector Comments sections for additional information.

Summary: N/A

Summary: New construction high density apartment complex being constructed.

Summary: Exposed soil consistent with site development activities and EMP.

Brownfields Inspection Report: Powers Site (RN), 20045-16-060
04/06/2022 10:28 AM
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Use of Basements: Observed Basement Violation: Yes

Storage of Chemicals: Observed Chemical Violation: No

Groundwater Monitoring Wells: Not Observed Monitoring Well Violation: No

Current Exposure to Public/Public Risk:

Summary: As identified in previous Site Inspection, soil contact walls are present. Liquid
Boot was to be applied to exterior of the wall per the design, however, initial walls were
backfilled without this taking place. Form boards along upper portion of the wall have
been removed since prior inspection, and approximately 50% of the interior wall has
been sprayed with Liquid Boot (Photo 1).

Summary: Numerous 55-gallon drums of Liquid Boot 2-part mixture present during
inspection.

Condition:
Summary: N/A

No risk to the public observed at the time of the site inspection.

Brownfields Inspection Report: Powers Site (RN), 20045-16-060
04/06/2022 10:28 AM
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IV. Inspector Comments

V. PHOTOGRAPHS

Photo 1: Liquid Boot VIMS barrier installed on lower level following previous Site Inspection.
Wood ledger boards were removed from top of concrete soil contact wall, and partial Liquid
Boot application is visible.
Site Inspection was performed following a phone call from Alexis McKenzie (H&H) that smoke
and coupon sampling would be performed at the Powers Site in approximately an hour. I
informed her that I would like to be in attendance during the testing and I left for the site.
When I arrived, as mentioned previously, the sub-slab VIMS piping issues appeared to have
been addressed, and the Liquid Boot VIMS barrier had been installed.

During the Site Inspection, three individual smoke tests were performed below the VIMS
barrier and coupon samples were taken at the frequency outlined in the VIMP (Photos 4-9).
David Walker with SCS Engineers was present for the smoke and coupon testing, and he used
digital vernier calipers to check that the barrier coupons met the minimum 60-mil thickness
specified in the VIMP (Photo 5). Following confirmation that the coupon thickness met the
minimum requirements, a larger patch of VI-20 Geomembrane was cut to overlap the barrier
surrounding the coupon sample, it and the surrounding barrier were sprayed with liquid boot,
then the sprayed side of the patch was pressed into the wet material, and the exposed green
side and surrounding barrier were sprayed with Liquid Boot to finalize the repair (Photo 6).

Brownfields Inspection Report: Powers Site (RN), 20045-16-060
04/06/2022 10:28 AM
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Photo 2: PVC solid chase/riser bridging footer trench with each end connected to GeoVent.
VIMS riser built into piping and pulling from both directions as designed, as opposed to an off-
center GeoVent branch within footer trench (4/4/2022 Site Inspection Report - Photo 7).

Photo 3: Hollow support stakes replaced with solid rebar since previous Site Inspection.
Brownfields Inspection Report: Powers Site (RN), 20045-16-060
04/06/2022 10:28 AM
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Photo 4: Coupon sampling after Liquid Boot application to confirm that the minimum allowable
thickness (60 mils) had been obtained.

Photo 5: David Walker with SCS engineers using calipers to check coupon thickness. This
coupon was measured at 60 mils, meeting the minimum coupon thickness requirement.
Brownfields Inspection Report: Powers Site (RN), 20045-16-060
04/06/2022 10:28 AM
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Photo 6: Repairing barrier following coupon sampling.

Photo 7: Vapor barrier partially inflated during smoke testing.
Brownfields Inspection Report: Powers Site (RN), 20045-16-060
04/06/2022 10:28 AM
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Photo 8: VIMS barrier penetration leaks on each side of footer trench during smoke testing.

Photo 9: Vapor barrier leaks observed in Photo 8 being sealed.