In both Connery and Harrington Elementary Schools, the existing gymnasium floors were composed of tongue & groove wood slats connected by steel splines. This is known as an “iron-bound” system, which was a common assembly in gymnasiums built in the 1930’s. In some areas, wood slats had already been replaced with plywood surfacing. However, there were still many areas where slats were misaligned, warped and bowed. Wear and tear was also evident along most existing door thresholds. In general, the wood surfaces were scraped, stained, faded, un-level, and loose. Hazardous materials testing by the City revealed asbestos was present within the original adhesive mastic below the wood slats.
The City of Lynn needed to replace these two gymnasiums floors over the summer so that the flooring would be ready for the following school year, all while staying within the School and City’s budget.
CBI first reviewed the existing conditions of the gymnasium floors at the Harrington and Connery Elementary Schools and provided options, with cost estimates, for replacing the existing deteriorated hardwood floors including pourable polyurethane sports flooring, hardwood tongue and groove, PVC interlocking tile, and synthetic membrane sports flooring. All options required complete demolition of the existing wood plank flooring and abatement of all hazardous materials down to the original concrete floor slab.
The City decided to replace the floors with synthetic membrane sports flooring system with painted game lines and graphics. Because the original wood flooring assembly was about one inch thicker than the new synthetic membrane assembly, a lightweight concrete underlayment was included in the flooring replacement design so that the new floor level would align with existing adjacent flooring outside of the gymnasium. The City also decided to include installation of a concrete slab over the original dirt floor in the building’s basement crawl space in the project.
Humidity was an issue during the slab replacement and CBI recommended a longer cure time for the concrete slab in the crawl space below the gymnasium as well as moisture monitoring prior to the new flooring installation. The concrete slab in the crawl space was installed over a vapor barrier membrane preventing moisture released during the concrete curing process from being absorbed into the earth below. For this reason the vapor was released upward into the crawl space and then absorbed by the concrete gymnasium slab. It was important to allow the moisture to pass through the first floor slab before installing the new gym flooring system so that moisture would not be trapped in the crawl space below.
An evaluation of both schools determined the existing framing would be suitable to accommodate the new concrete slab overlay along with the new synthetic flooring.