The curtain is going up on a big show outside the Mondavi Center for the Performing Arts.

In this case, the curtain is scaffolding all along the building’s south wall, from the ground to the roof. Workers will be removing all of the sandstone — an estimated 50,000 tiles — to repair the waterproofing underneath.

The project is expected to last into December. During this time, the real show, inside the center, will go on as scheduled.

The scaffolding, scheduled to go up around the end of the month, will be enclosed in mesh to protect the workers from the elements. In addition, the beige-colored mesh will minimize the visual disruption.

After removing the stone, the workers will replace the sheathing and the waterproof membrane, to stop rainwater from getting inside, as has happened periodically since the center’s construction 10 years ago.

The stone tiles will not come off easily — in fact, they are likely to be broken into pieces, irregularly shaped, so much so that they will not be suitable to go back on the wall. The replacement tiles will come from the same quarry in India that supplied the tiles for the original construction.

The Mondavi Center’s general contractor, McCarthy Building Cos., is doing the work under a mediated settlement with UC Davis, said Assistant Vice Chancellor Clayton Halliday, campus architect. He said the settlement includes a confidentiality clause, preventing the parties from disclosing the terms.

The university and McCarthy and its subcontractors worked through all the issues amicably, Halliday said, and UC Davis retains its good relationship with McCarthy— which, subsequent to the Mondavi Center, built the Activities and Recreation Center, the Student Health and Wellness Center, and is now at work on the Segundo Services Center.

Leakage tied to wind speed, rain angle

Alex Achimore, senior project manager with UC Davis’ Design and Construction Management, said the Mondavi Center's water inlfiltration problem usually occurs only when the wind is of sufficient speed to push the rain into the wall at a certain angle.

The university and McCarthy conducted extensive testing of the wall to zero in on the problem and develop the solution. It is not an easy one.

The waterproof membrane goes on as a liquid, like paint, and solidifies on the sheathing that goes over the building’s frame. Therefore, workers must remove the sheathing, and, to get at the sheathing, they must remove the sandstone and the mortar under the stones.

“Unfortunately, the stones are bonded to the sheathing and will not come off in such a way that they could be reused,” Achimore said.

“We are applying new sheathing and new waterproofing, and the stones will be set in place over a half-inch mortar bed that is made by the waterproof membrane manufacturer, so that they are compatible and bond.”

Achimore joined the contractor’s representatives in making a trip to India to ensure the new sandstone will be a good color match for the stones that will remain on the rest of the Mondavi Center.

Besides working on the south wall, the contractor will replace the waterproofing (and the stones) around the windows and doors on the north and west sides of the building, and on the Mondavi Center’s front, specifically where the canopy connects with the building.

The project also involves waterproofing repair on the box office.

Earlier this year, workers completed waterproofing repair on the Mondavi Center’s glass front, including the tie-ins to the box office.

Project website.