Horticulture building excavation uncovers fly ash; board warned of schedule delay

Project manager Craig told the board that site excavation for the new horticulture building uncovered fly ash and other unsuitable soils that required environmental testing and remediation. "We have currently about a 37 day delay in our schedule," Craig said, explaining that the discovery halted foundation work while engineers evaluated whether material could be amended and reused or needed removal.

Craig and staff said engineers devised an amendment plan that included testing, amendment and selective removal to make the soil structurally sound where possible. That engineering and environmental work paused foundation and slab work on the project's critical path and pushed the certificate of occupancy projection to July 18, 2025, later than the team's original target to turn the space over before the start of the next school year.

To mitigate the delay, the contractor and school agreed to pursue schedule-recovery measures such as adding crews, permitting weekend and evening work and installing time-lapse cameras to monitor progress. Craig said the team is also evaluating insurance, grant and donation funds and will spend grant monies first where deadlines require fiscal-year spending by June 30.

Board members asked whether additional geotechnical borings could have detected the pocket of contaminated material; Craig said multiple borings and environmental checks had been done but that the contamination was present in pockets the earlier borings missed. He described the discovery of historic debris at the site and said soils behind a tree line had been inaccessible to initial tests.

Staff said foundations were scheduled to be poured in coming weeks where amended soil meets structural requirements; slab work remains at risk of winter conditions and the team is working to bring the schedule forward where possible.