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Home My WebLink About20045_Powers Site_SIR_20220404 DWM Brownfields Inspection Report Submitted By: jkslaughter_ncdenr Submitted Time: 04/05/2022 3:32 PM I. Inspection Information Date & Time: 04/04/2022 11:10 AM Inspection Type: Meeting Brownfields Staff: Kevin Slaughter Other Personnel: Christie Zawtocki & Alexis McKenzie - H&H, Steve Lamb and David Walker - SCS Engineers, and construction superintendents and VIMS installers. Location: Lat: 35.2112151, Long: -80.8698847, Brownfields Inspection Report: Powers Site (RN), 20045-16-060 04/04/2022 11:10 AM Page 2 of 7 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: None 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: When performing the Site Inspection, there were numerous items with the methane mitigation system that did not match the DEQ approved methane mitigation design. Liquid Boot was not applied to the exterior of the soil contact walls on the western portion of the property prior to them being backfilled (Photos 1 and 2), GeoVent was installed within footer trenches, and no solid PVC piping was used to bridge the footer trenches in a perpendicular direction, with GeoVent being installed across the bottom of the trench, and up the other side (Photos 3 and 4). In addition, the VI-20 membrane was installed, and at least one coat of Liquid Boot applied on the northern portion of the slab prior to the gravel sub-slab piping inspection. The barrier t had been partially opened prior to my arrival (Photo 5). In addition, some of the locations of the GeoVent had been moved, including to one riser, a PVC sub-slab monitoring point had not been located, one sub-slab monitoring point terminated within a footer trench, and hollow stakes were used (Photos 1, 6 and 7). See Use of Basements and Inspector Summary: N/A Summary: New construction high density apartment complex being constructed. Summary: Consistent with site development activities, and EMP. Brownfields Inspection Report: Powers Site (RN), 20045-16-060 04/04/2022 11:10 AM Page 3 of 7 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: Upon my arrival, H&H pointed out that there were numerous deviations from the DEQ approved methane mitigation design. One of these was the backfilling of occupied space concrete soil contact walls prior to application of Liquid Boot on the soil contact side of the wall (Photos 1 and 2). Following written approval by the product manufacturer, H&H will propose to DEQ that Liquid Boot be applied to the interior of these walls, with an interior wall constructed to cover the interior Liquid Boot application. According to the Site Superintendent, this wall will be constructed so that it is not attached to concrete wall, and therefore, no penetrations of the Liquid Boot application would occur in its construction. Summary: Numerous 55-gallon drums of 2-part Liquid Boot product staged on different portions of property. Condition: Summary: N/A No risk of exposure observed at the time of the Site Inspection Brownfields Inspection Report: Powers Site (RN), 20045-16-060 04/04/2022 11:10 AM Page 4 of 7 IV. Inspector Comments V. PHOTOGRAPHS Photo 1: Project superintendent team, GeoVent/Liquid Boot contractor, H&H and SCS personnel in photo on lower-level section of apartment building. Issues with untreated backfilled concrete walls, and GeoVent installation being discussed. Hollow metal stake visible in lower left of photo holding up 1” dia. PVC electrical conduit. The Site Inspection was performed to coincided with an installation inspection (gravel/sub-slab piping) being performed by H&H and SCS engineers. There were numerous installation issues as identified in Vapor Mitigation Systems and Basements Summery above. Based on discussions during the Site Inspection, all of the items identified (except for the Liquid Boot application to the exterior of the backfilled wall) will be corrected so the system installation matches the previously approved methane mitigation design. H&H to contact DEQ for a follow-up gravel/piping inspection once these repairs are completed, and prior to Liquid Boot application to interior wall. Brownfields Inspection Report: Powers Site (RN), 20045-16-060 04/04/2022 11:10 AM Page 5 of 7 Photo 2: Partial view of soil contact interior wall. Waterproofing was applied to exterior of wall, and it was backfilled with soil prior to applying Liquid Boot as called for in the design. Photo 3: GeoVent installed perpendicular to several footer trenches without solid PVC bridging trench depressions as called for in approved design. Brownfields Inspection Report: Powers Site (RN), 20045-16-060 04/04/2022 11:10 AM Page 6 of 7 Photo 4: Example of GeoVent installed within footer trench. Photo 5: Portion of VIMS barrier installed and sprayed with Liquid Boot prior to gravel/sub-slab piping inspection. VIMS barrier opened prior to my arrival. Brownfields Inspection Report: Powers Site (RN), 20045-16-060 04/04/2022 11:10 AM Page 7 of 7 Photo 6: Sub-slab monitoring point terminating within a footer trench. Photo 7: VIMS Riser installed at the end of a GeoVent “branch” not shown in design (also within a footer trench). The riser should have been installed along main GeoVent line and not on a side branch, with GeoVent exiting both sides of PVC “T” at base of riser.