Concrete Waterproofing Alternatives
Crystalline Waterproofing
Instead of using a separate membrane, crystalline technology provides concrete waterproofing for new construction by using any or all of the available application methods. A crystalline admixture can be added directly into the concrete mix at the batching plant (preferred) or on-site (for small batches) for most concrete elements. In addition, a slurry mixture can be used to cover joints and seams or untreated concrete and be applied by brush or spray methods. For new concrete slabs or decks, a dry-shake formulation can be troweled into the fresh concrete prior to finishing.
All of these methods provide a continuous waterproof surface across the concrete without any seams. As such, crystalline waterproofing eliminates the need for separate membranes. (Note that a drain tile system along the base of a wall around the perimeter is still recommended). This usually provides significant cost savings compared to the installation of a membrane of any type. Further, it is notably more cost-effective to use integral products (admixture and dry shake) during new concrete construction than an applied coating after the wall is completed.
Some of the characteristics of new construction using crystalline concrete include the following:
- Resistance to extreme hydrostatic pressure: The pressure of water on a concrete wall is what drives many water leaks. Crystalline concrete will resist this effectively whether applied on the positive (exterior) side or the negative (interior) surface of the concrete.
- Integral application: The crystalline treatment becomes a fully integral part of the concrete substrate. It does not require sealing, lapping, and finishing of seams as with membranes. It cannot puncture, tear, or come apart at the seams
- Chemical resistance: Aggressive chemicals found in many subsurface and concrete construction locations are not a problem for crystalline applications since most do not affect the crystalline structures.
- Crack sealing: All concrete will develop some cracking as it cures. Crystalline admixtures can fill and seal static hairline cracks up to 0.4 millimeter wide.
- Human safety: Crystalline applications are nontoxic and contain zero volatile organic compounds (VOCs).
- Cost: It is routinely less costly to incorporate crystalline technology for waterproofing when compared to most other methods.
- Permanence: As noted, the crystalline admixture becomes a permanent part of the concrete that will remain in place for the full lifespan of that concrete.
- Abrasion resistance: Some formulations are available that provide greater resistance to abrasion where required.
- Construction scheduling: As an admixture, crystalline waterproofing is added to the concrete at the time of batching and therefore is not subject to climatic restraints. Further, it does not require protection during backfilling or during placement of steel, wire mesh, or other materials. All of this increases the flexibility in time scheduling and helps projects meet or even beat construction deadlines.
Due to this significant list of properties, crystalline concrete has been used successfully in new construction for commercial buildings, industrial settings, institutional facilities (hospitals, schools, higher education, etc.), multifamily housing, and even high-end single-family homes. All have received the waterproofing and other protective benefits of this technology applied during new construction and realized over the full life of the building.
NEW CONSTRUCTION CASE STUDY 1
Project: Golden1Center
Location: Sacramento, California
Owner: Fulcrum Capital Group
Architect: AECOM
Contractor: Turner Construction Company
The Project: After nearly 20 years of discussions, an arena for the NBA’s Sacramento Kings, named Golden1Center, was finally under construction in downtown Sacramento, California. The very existence of the arena, which has sparked revitalization of downtown Sacramento, is due mostly to the efforts of two determined players. They are the Kings’ chairman Vivek Ranadive, who led the investment group that prevented the team’s proposed move to Seattle, and Sacramento’s Mayor Kevin Johnson, who successfully pushed for a $255-million city subsidy. The Kings are funding the remaining $222 million.
The Challenge: After the initial pour of more than 300 foundation piles, it was discovered that half of them had filled with 4 inches of groundwater. This was due to extreme hydrostatic pressure, resulting partially from the nearby convergence of the Sacramento and the American rivers. Needing to seal the pile caps, whose size ranged from 5 feet x 8 feet to 15 feet x 20 feet, waterproofing contractor F.D. Thomas sought a waterproofing material that could be applied and cured quickly to keep to the schedule and because a storm was coming.
The Solution: After a site inspection, it was confirmed that a brush application of crystalline concrete treatment applied at 2 pounds per square yard followed by a heavy spray of a second coating within 4 hours would serve as the stand-alone waterproofing mechanism for the pile caps at this critical juncture. After the design team and construction manager and general contractor Turner Construction approved the use of this approach, all the pile caps and re-bars were coated and cured the same day. This solution provided a nontoxic chemical treatment for the waterproofing, and protection of concrete by generating a nonsoluble crystalline formation deep within the pores and capillary tracts of the concrete—thus providing a permanent seal against the penetration of water and other liquids.
Results: The $477-million, LEED-certified sports and entertainment arena was completed on time for the 2016–2017 basketball season.
NEW CONSTRUCTION CASE STUDY 2
Project: 327 Royal Palm and Tower 155
Location: Boca Raton, Florida
Architect: Vander Ploeg and Associates
The Project: 327 Royal Palm and Tower 155 are designed by the same firm but are projects with decidedly different concrete foundation systems. 327 Royal Palm is a hydrostatic slab with deep piles ranging from 30 to 35 feet below grade, with a total dynamic head pressure (TDH) of 22. Tower 155 was a matt slab ranging from 42 inches to 6 feet in depth, with piles 20 feet below grade and a TDH of 20.
The Challenge: Due to the high population density around the site and construction restrictions, the below-grade foundation concrete placements had to be done in multiple segments. The parking garage at Tower 155 is two levels below grade with the presence of extreme hydrostatic pressure. The area’s water table is 3.5 feet below the ground level, so making sure the structure is watertight was extremely important.
The Solution: Derek Vander Ploeg, president of Vander Ploeg and Associates, reports that the firm specified crystalline concrete on both of these projects. Crystalline admixture is being used throughout the mat slab, walls, pool, spa, and spa fountain for a total application area of 6800 cubic yards. A sheet waterproofing system was also considered, but due to space constraints and its difficult installation process, the crystalline waterproofing system was the best choice. When asked what made Vander Ploeg decide to use crystalline concrete, he replied it was “due to limitations in construction logistics, such as tight space allocation, thus difficulty installing membranes, and the need to accelerate the construction schedule due to the densely populated area. Both were critical elements in deciding to use crystalline concrete. Plus cost savings was also a significant benefit.”
A vast quantity of concrete was used in Tower 155, so placement of concrete was significantly enhanced from every perspective using crystalline concrete. Vander Ploeg says, “With all the cold joints in the slab and walls due to the mass amount of concrete and many separate pours, there is not a leak anywhere. Both projects are dry. The technology is amazing, and it really works well under pressure.” He also comments that the crystalline technology used made both of the slabs “beautiful,” and adds, “It seems the finishers had extended working time, thus really improving the finish on 8,000 psi concrete.
Results: By choosing crystalline concrete technology, the project saved 28 days on the construction schedule.
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