A new office building designed by Abramson Architects located at 5237 W. Jefferson Blvd in Los Angeles is situated on a former gas station and car service facility. The entire 54,393-square-foot site will include a three-story office building with approximately 72,000 square feet of available space and a three-story below grade parking garage with 185 covered spaces. The building will also feature a roof terrace.
The building’s foundation sits just above the water table, and significant vapor intrusion concerns arose due to the site’s previous use as a gas station. These conditions required a preventative measure, and the below grade system had to mitigate both potential water and vapor intrusion. Due to site access restrictions for heavy equipment, the material also had to be light enough for laborers and easy to stage for installation.
WATERPROOFING MEMBRANE
EPRO’s PreTak HW, a HDPE self-adhesive pre-applied waterproofing membrane with seams designed to be heat weld capable, was selected to protect against water ingress and the environmentally impacted soil. The specification called for a continuous full bathtub application, meaning the system needed to run uninterrupted from under the slab and up the vertical blindside walls. PreTak HW’s ease of application, tested performance, and overall cost effectiveness were the deciding factors for the waterproofing consultant and general contractor at this site.
PreTak is available with two selvedge edge options. One version includes a factory-applied adhesive edge on both sides of the sheet to create a secure bond at the seam. The other version, utilized for this project, omits the factory-applied adhesive selvedge to allow for a thermal fusion of one piece of HDPE to weld to another piece of HDPE at the seam. Installation is efficient and reliable with a marked adhesive selvedge, which allows for easy application at seam overlaps.
SOLUTION APPROVED
PreTak delivers superior performance in harsh conditions and can withstand follow-on trade construction traffic and all types of environmental conditions, post installation. PreTak is City of Los Angeles-approved as a waterproofing and methane barrier (LARR #26164) and for shotcrete.
“One of the benefits of the product was that it was hot-air welded, so this definitely saved us some time on site,” says Kevin Burpee, senior superintendent, Suffolk Construction, the general contractor.
As an added bonus and site requirement, the PreTak rolls were lightweight and did not require additional heavy machinery to lower them into the excavation.
“The mat foundation system had thickened areas so we could not utilize equipment in the hole but the size of rolls was manageable by hand,” explains Burpee. “This meant that the only equipment required to lower them into the 40 ft deep excavation stayed on the street. On a site like this, it was key to maneuvering the material and getting it applied quickly and easily.”
CLOSING THOUGHT
Leasing began in OCTOBER 2023 at 5237 W. Jefferson Boulevard. The structure is located in a rapidly developing opportunity zone, anticipated to experience further development in the future.
For More Information:
For more information about EPRO’s PreTak HW, a HDPE self-adhesive pre-applied waterproofing membrane, visit www.eproinc.com.
Modern Contractor Solutions, October 2023
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