THE CHALLENGE
The Director of the Council on Aging noticed cracks at the surface of the some the VCT tiles in the “Main Hall” of the Senior Center building. The condition continued to worsen so CBI was engaged to provide an existing conditions analysis, review contractor exploratory investigation, and prepare a report with recommendations and a cost estimates for VCT flooring and slab repairs.
CBI’S SOLUTION
The tile in the Main Hall consists of a single layer of 12’ x 12” VCT that was worn throughout. We observed several linear cracks which appeared to continue across several tiles and appeared to run at least ½” deep (vertically) at points. These types of cracks are not typical of general wear and tear of VCT tile, and could reappear if the VCT is replaced with new tile without first addressing any underlying problems.
After CBI reviewed drawings of the original construction and a more recent addition/renovation project which occurred in the 1990’s, it appeared that the cracks showed up near the location where walls and unit vents were removed as part of the addition/renovation project. It was initially unclear whether these areas alone just started experiencing deterioration at the slab because of the renovation work, because of accelerated moisture infiltration, shrinkage of the concrete, or some other factor(s).
Test cuts were performed at the cracked tiles and the slab below so that we could visually inspect the actual conditions, the thickness and reinforcing of the concrete slab, and the presence and condition of any under-slab vapor retarder. We found that the soil had minor settlement under the slab along the perimeter of the exterior wall and also at an area on the northeast corner where a wall had previously been removed and slab extended during the 1990’s renovation. We also found that the vapor barrier was not continuous around these problem areas, but persistent delamination was not evident throughout.
CBI recommended terminating new replacement tiles slightly short of the exterior foundation wall so the slab could move without causing the tiles to crack. We recommended a wider vinyl cove base or strip of wood trim be installed to cover the edge of the tiles.
CBI recommended that a portion of the existing concrete slab above the abandoned wall at the northeast corner of the room be opened and the abandoned concrete foundation be removed so that compacted soil could be filled in and the slab and vapor barrier could be extended under the full area. CBI also recommended grinding the floor surface in areas to level the concrete, and filling in dips with a Portland cement leveling compound rather than gypsum cement.
CBI prepared the Bidding Documents, including details and specifications, and the work was completed in 2013.
