The design is one of the oldest in the world. The technology used to protect it from weather is one of the newest.
This 10-story stepped pyramid in Sacramento, known as the Ziggurat, is HQ for California’s Department of General Services. Though the Ziggurat was constructed in 1997, it hearkens back to 3,000 BC when ziggurats first appeared as platforms for temples in Mesopotamia.
We know that area now as adjoining parts of Iran, Iraq, Syria, Turkey and Kuwait.
Ancient ziggurats were usually made of sun-baked bricks faced with fired bricks glazed in different colors.
Sacramento’s Ziggurat, designed by E.M. Kado Associates, Sacramento, is faced with Minnesota Gray Buff limestone.
Project Manager Chris Hill, WSP Roofing & Waterproofing, Sacramento, oversaw cleaning and weatherproofing of the pyramid in autumn and winter 2012 and spring 2013. His crew stripped out and replaced bad caulk joints and pressure-washed to remove traces of biological staining.
To ensure the staining stayed gone, he treated the cleaned stone with Weather Seal Natural Stone Treatment WB Plus, one of PROSOCO’s newest masonry water repellents. Keep out water, of course, and you keep out the problems water brings, like biological staining, as well as wet-dry and freeze-thaw cycling.
The treatment made the shortlist of three candidates for the project, Chris said, after he asked the quarry that supplied the stone for suggestions. Chris got an unqualified endorsement for PROSOCO protective treatments. He asked Manufacturer’s Representative Tim Sinnott, Sinco Sales, Danville, Calif., to suggest a specific PROSOCO product.
Tim recommended PROSOCO’s newest water repellent for limestone and other stone masonry after consulting with PROSOCO’s Lab.
“Natural Stone Treatment WB Plus provides better water-repellency and bonds much more tenaciously to calcareous stone than the standard water-based water-repellents,” says PROSOCO Research and Development Chemist Chris Moore. “It does it without the blushing or whitening sometimes associated with these water-based products.
“It’s a modified siloxane, but it’s modified in a way that no one has ever tried before, to my knowledge,” says Chris, who created the new protective treatment in 2012.
The Lab tested the new treatment according to ASTM C97, among other tests, which measures by weight how much water a piece of treated stone absorbs after being immersed for 24 hours, compared to an untreated control.
“I expected about an 84 or 85 percent improvement compared to the untreated stone,” Chris says. “I knew we had a winner when it showed a 96.6 percent improvement. We pulled the treated stone out of the water after 24 hours and it was practically dry.”
In addition to effectiveness, the penetrating, breathable water repellent met two other checkpoints. It complied with California’s strict Volatile Organic Compound (VOC) regulations, and it had no effect on the stone’s appearance.
H.D. Supply/White Cap Construction Supply, Roseville, Calif., supplied the Natural Stone Treatment WB Plus, and Chris Hill and crew sprayed it onto the dense stone, then backrolled it, stone by stone. They weatherproofed from the top down, treating each level’s North, East, South and West elevations in turn.
Portions of the odd-shaped building were hard to reach, Chris said, such as the recessed ridges over the entrance and rear exit. To reach those with their sprayers and rollers, WSP crew members used an all-terrain lift with basket. In other places they had to harness up like mountaineers.
“We used lots of scaffolding,” Chris said. “After we finished each level, we had to disassemble it, hand it down to the next level and reassemble.
By project’s end, Chris and his team had weatherproofed 61,250 square feet of limestone pyramid with PROSOCO’s new Natural Stone Treatment WB Plus — a new technology for an ancient design. ###