Story at a glance:

  • Brownfield redevelopment projects require carefully thought plans, including an in-depth assessment of the soil.
  • Pre-applied membranes can help prevent harmful gases in the soil from seeping into the structure.
  • GCP’s PREPRUFE Plus waterproofing membrane has proven protection from both water as well as ground contaminants and various gases.

With urban space at a premium in the US, developers are finding it difficult to locate unspoiled sites to build on. Centuries of industrial development have left countless lots contaminated. Often these are abandoned industrial sites like steel mills or refineries, which are referred to in some regions as brownfields. In some cases developing on these sites is not wise due to health and safety hazards and/or the high cost of the cleanup, but many sites are viable for building if properly remediated.

Redevelopment Challenges

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In Pittsburgh, the three rolling steel mills were preserved to make up what is now known as Mill 19. Photo courtesy of Ten X Ten

When embarking on a redevelopment project, it’s critical to have a plan in place for remediation. This will involve ordering an in-depth assessment of the soil and the nature of its contaminants as well as getting expert advice on the most effective remediation techniques available. It is critical to comply with the latest regulations. It’s common for multiple remediation approaches to be used inside and outside of the structure. A geotechnical engineer can provide recommendations that are specific to the particular site.

The Need for Pre-Applied Membranes

Often part of the remediation process involves treating the first few layers of soil or removing several layers of soil from the site. However, this will most likely leave traces of volatile organic compounds behind. This means it is also essential to prevent harmful gases in the soil from seeping into the structure. Pre-applied membranes can offer this protection. They prevent contaminants in the ground from corroding the structure or migrating inside and degrading the air quality.

How Pre-Applied Membranes Work

Pre-applied membranes are laid before the foundation is poured. The membrane is placed directly against the soil retaining systems. The concrete is then poured directly onto the membrane. As the concrete on the foundation slab and walls hardens, it forms a bond with the membrane.

Different Kinds of Pre-Applied Membranes

One might assume that any pre-applied waterproofing membrane would also protect against hazardous chemicals (ground contaminants) and gases. However, most pre-applied membranes do not offer both protection against water and harmful gases. Some waterproofing membranes will break down over time when exposed to certain contaminants. Others may not have the tight, integral bond to keep vapors out. The PREPRUFE Plus waterproofing membrane from GCP has proven protection from both water as well as ground contaminants and various gases—including methane.

A Superior Membrane Waterproofing Solution

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Photo courtesy of GCP Applied Technologies

The PREPRUFE waterproofing membranes provide a continuous layer of protection. It prevents water migration into and around the structure thereby protecting the concrete from deterioration caused by the chlorides and sulfates in groundwater or aggressive soils.

A big advantage the PREPRUFE system has over alternative waterproofing membranes is that it is applied as a single layer with Dual Adhesive ZipLap, which means less opportunity for error during installation. The membrane is a composite sheet comprising three layers—a durable high-density polyethylene (HDPE) film, a pressure-sensitive adhesive layer, and a patented weather and dirt-resistant protective layer (suitable for foot traffic without protection). Alternative solutions cannot match this simplicity and will typically need to be applied in several layers or with a wide range of ancillary materials and specialized equipment.

The PREPRUFE membrane can be installed much faster than a traditional loose-laid PVC system, with its welded seams and compartments or fleece membranes. This benefit alone can result in significant cost and time savings for contractors on site. In addition to schedule acceleration, PREPRUFE technology offers superior waterproofing performance for the design life of the structure.

A high-performance, adhesive bonded waterproofing membrane like PREPRUFE can improve the concrete’s long-term structural performance and durability by providing constant protection from sulfate, chloride and water ingress, offering the ultimate solution for projects where failure isn’t an option.

Versatile and Reliable

Compared to alternative methods of waterproofing PREPRUFE is significantly better suited to handle the unpredictability of site conditions. It can be applied directly to compacted soil or mud slab or compacted gravel and is immediately ready for rebar and concrete placement—without the need for protection layers. Though it can be used immediately, the membrane is designed to withstand the jobsite environment and can be left exposed for a minimum of eight weeks without protection. This allows plenty of time for concrete pouring or other site work, giving contractors much more flexibility in their schedule than competing technology.

Critical to the performance of the system, PREPRUFE does not rely on the mechanical bonding of fibers or variable hydration and/or activation processes as do the majority of alternative membranes. It can withstand a head of water of more than 231 feet at laps and its Advanced Bond Technology provides an impermeable barrier to liquid water and moisture. Poured concrete aggressively adheres to PREPRUFE forming a continuous adhesive seal and preventing water migration between the waterproofing layer and the structure – substantially reducing the risk of leaks.

A Complete Solution

GCP’s complete systems-based approach to waterproofing offers an extensive range of fully compatible products and accessories that provide effective enveloping of structures and create a flexible, fully adhered waterproofing barrier.

In addition to providing high performance technology, GCP works closely with its clients to tailor its solutions to meet the needs of individual projects and deliver the correct waterproofing solution for the project.

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