With urban space at a premium in the U.S., 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 such as steel mills or refineries, which are referred to in some regions as brownfields. Obviously, there are cases where developing on these sites is not a wise choice, due to the level of health and safety hazards and/or the high cost of the cleanup. However, many sites are viable for building, if properly remediated.
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, and 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 down 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.
Not all pre-applied membranes are the same
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
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 there is 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 (which is 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 231ft 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.