The application of liquid waterproofing membranes is a key aspect of modern foundation protection systems. Traditional methods are well established in the industry, including by brush, roller or spraying using a single-component pump.
Beyond these classic techniques, however, specific specialized approaches make it possible to optimize the performance of the system, speed up execution and ensure a consistent result. This includes co-spraying. This process involves the simultaneous application of two components that react directly on the support.
In the case of bitumen emulsions used for foundation waterproofing, it consists of applying the liquid membrane and an additive, usually a saline solution, from two separate nozzles. This interaction triggers a rapid reactionpon contact with the substrate, promoting the quick formation of a continuous, uniform and high-performance layer.
The Role of the Saline Solution in Co-Spraying
Adding salt to water alters the physicochemical properties of the bitumen emulsion, which directly influences its behaviour during co-spraying. The saline solution acts as a destabilizing agent, causing the emulsion to break down in a controlled manner as soon as it is deposited on the surface.
This results in the rapid expulsion of the aqueous phase, without relying solely on a slow evaporation process. The liquid film thus forms and stabilizes more quickly.
Significant Reduction in Drying Time
The main advantage of adding saline solution is the marked decrease in curing time. The membrane becomes dry to the touch quickly, is less affected by site conditions and is ready sooner for the next construction steps.
Wider Temperature Range
The rapid breaking of the emulsion also allows work to be carried out over a wider temperature range, increasing installation flexibility, particularly at the beginning or end of the season.
The Benefits of Co-Spraying
When bitumen emulsion and saline solution are applied simultaneously, their contact causes an immediate chemical reaction leading to the formation of a continuous, homogeneous and touch-dry waterproofing membrane.
This technique ensures a uniform seal thanks to consistent coverage that conforms to the irregularities of the support. This monolithic layer without joints or overlaps reduces the risks of water infiltration and results in labour savings due to the speed of application and drying, as well as a flameless installation that enhances workplace safety.
Equipment Required
The equipment required to co-spray COLPHENE LM 3200 is similar to that used for COLPHENE LM BARR SPRAY. The process relies on two distinct systems, each playing a specific role in the chemical reaction.
The bitumen emulsion is sprayed at high pressure, typically around 1,500 psi, ensuring uniform and controlled application of the liquid membrane. The saline solution is applied simultaneously with a smaller multi-purpose device fitted with a separate nozzle to trigger the reaction upon contact.
The choice of pumps, nozzles and accessories must be adapted to the site conditions, the required flow rate and the type of waterproofing system. The recommendations for the use of the equipment provided by the pump supplier must be followed to ensure the compatibility and performance of the co-spraying process.
Surface Preparation
Co-spraying requires no additional surface preparation compared to conventional liquid membrane installation methods. However, the system’s performance depends on the condition of the substrate, which must be clean, dry, and free from any contaminants that could impair adhesion.
For detailed information regarding surface preparation, application requirements and product installation, it is recommended to consult the COLPHENE LM 3200 technical data sheet, which remains the official reference to be followed on site.