Tasman East is a new development in Santa Clara, CA, consisting of two adjacent buildings, Tasman East Apartments and Tasman East Atria: Two residential towers, one 20-story Home for the Ambulatory Aged, and one 22-story rental housing tower. The full development of the area, also known as the Tasman East Specific Plan, includes 509 residential units, 191 senior assisted living units, 19,410 square feet of retail, 15,737 square feet of flexible and amenity space and a 0.5 acre park.

The site had both hydrostatic conditions in the form of shallow groundwater and methane gas due the project’s proximity to a former landfill. An additional challenge presented itself once construction had begun; the foundation was atypical with a lot of angles and changes in elevation. This meant that the site required a product that was easy to install and could easily conform to the foundation.

Additionally, in the current economic climate, developers are under pressure to minimize construction costs while maintaining high performance standards. PreTak outperforms similar systems and also results in substantial cost savings for the client. Ultimately, with this project, the developer selected EPRO’s PreTak, to meet the budget and keep the project on schedule.

EPRO’s PreTak and PrimeTak post-applied membrane were installed across approximately 230,000 square feet to form an underslab and blindside waterproofing and methane barrier.
“Installation went faster than expected,” said Nathan Shamosh, Gergen/JSS Construction, the EPRO installer.

PreTak transitioned to the self-adhesive membrane, PrimeTak, at locations on the mat slab that required post-applied waterproofing.

“PreTak was installed over the entire building footprint,” says Shamosh. “The large roll widths and excellent seam adhesion made this the perfect product to cover large areas.”

Due to the extremely tight schedules, PreTak was installed with Hydrolap seams, which allowed for a lightning fast installation due to its ability to form fully adhered seams in varying weather conditions.

“The owner was looking for a system that could keep up with the schedule, was cost effective, and most importantly, provided superior protection,” says Shamosh. “Going with PreTak met these needs, and ultimately helped us beat a tight construction schedule.”

PreTak is a pre-applied vertical and horizontal high-density polyethylene (HDPE) sheet waterproofing membrane combined with a pressure sensitive adhesive that fully adheres to cast in place concrete and shotcrete to prevent lateral water migration in both blindside shoring and underslab applications. Installation is productive and reliable with up to 8 ft wide rolls to minimize seams and dual factory-adhered Hydrolap selvedge with specially formulated adhesive for superior seam adhesion, even in environmentally challenging, wet conditions.

“The most challenging aspect of the project was transitioning from PreTak to PrimeTak in key areas. The EPRO team was responsive to changing field conditions and provided site specific details,” says Shamosh. “EPRO’s fast turn around time had a big impact on our ability to stay on schedule.”

Tasman East is scheduled to be completed in 2024. The architect is Steinberg Hart, the general contractor is Related California, and the EPRO installer is Gergen/JSS Construction. The building envelope consultant is WSP.