GCP Waterproofing "Saves" San Francisco's Transbay Transit Center

At least 30 feet (9 m) below the water table, the hydraulic forces compressed the worksite on all sides and made the walls weep immediately when the extraction pumps, otherwise chugging around the clock, stopped working. So close to the Bay Area, the stresses at work were immense on waterproofing the gargantuan Transbay Transit Center in San Francisco' city centre. 

The problem: an asphalt-based fabric for below-grade waterproofing could not cure under the adverse site conditions. The $4.185 billion project had plunged two and a half months behind schedule. 

Luckily, project manager for the waterproofing contractor Dean Edwards knew what to do. 

"We brought (GCP Applied Technologies) to the table", Edwards said. "We explained that PREPRUFE^® is a pre-applied, zero-cure waterproofing membrane. No waiting, and proven across hundreds of major infrastructure projects over the past 20+ years. What’s more, I believe in it. By taking curing off the table, we knew we could expedite the schedule". 

Much like its aid in sealing the Sacramento Kings' arena in no time and keeping one of the largest infrastructure projects in the Middle East—the Haramain High Speed Railway—on track, GCP's Preprufe once again proved it is the "gold standard of the business", said Edwards. 

With more than 500 million square feet (46 million m2) installed across hundreds of high-profile public and private projects worldwide, Preprufe waterproofing membrane is designed to deliver… 

• Fast, easy and straightforward installation
• A robust product design able to withstand wet weather
• Permanent adhesive bonding of the strong HDPE barrier to the concrete
• A clean, neat, asphalt- and clay-free product that is highly resistant to contaminated and aggressive soils
• Immediately trafficable with same-day rebar setting and tying

With the Preprufe fully installed, the massive job is back on schedule and Edwards now has time to rest easy on the dry construction site. 

"We’ve been actually waiting on the general contractor to catch up with us". 

Preprufe outperforms the competition

GCP Applied Technologies’ patented ADVANCED BOND TECHNOLOGY™ enables Preprufe to adhere directly to wet or dry concrete and to form an intimate and impenetrable seal. Unlike mechanically attached bonding technologies which risk water migration between the mesh interface and concrete, Preprufe is designed with synthetic adhesive layers and is combined with a robust HDPE film, providing a permanent physical barrier that protects structures against water and moisture, and chloride and sulphate attack even if their concentration changes over time.

Preprufe is a durable and flexible waterproofing membrane that withstands harsh site conditions for a longer period of time than competitive waterproofing membranes. It can be walked on during installation without risking damage and is considerably faster and easier to install and detail than mechanically attached membranes. Protective layers of concrete or boards are eliminated, reducing the depth of excavation and spoil, whilst the number of additional materials required with mechanically attached technologies is minimised.

>> Read full article on architectmagazine.com San Francisco's Transbay Transit Center builders applied GCP's PREPRUFE^® waterproofing membrane when nothing else would work.