When junior architects or contractors are starting out, they get bombarded with new terms and a whole new language, so we want to make it our mission at W. R. MEADOWS to ensure everyone understands the most commonly used concrete, waterproofing, and construction terms. To that end, we recently were asked, “What’s the difference between positive-side and negative-side waterproofing?” Today’s blog serves to answer that question.
The first thing to know is that positive-side waterproofing is on the outside of the structure, which is sometimes referred to as the “wet” side of the wall. This prevents any water from entering the structure. In some situations, such as a swimming pool or water reservoir, the positive side would be on the inside of the pool or tank. Prior to providing a waterproofing solution, it is important to determine where the water is, or which side is the “wet” side. Positive-side waterproofing is normally done on new construction. Once you’ve completed the concrete pour and have removed the forms, this is the stage when you install the waterproofing material. You can either use a sheet-applied or a fluid-applied material, depending on your project’s requirements, and your contractor’s preference.
Negative-side waterproofing is normally done when there is an existing wall and there’s no way to get access to the outside (positive-side wall) to waterproof it. A typical example where this situation plays out would be with an existing below-grade, occupied space in a high-rise building in any downtown area. If there’s a building right next door, which is often the case, there is no space between the two buildings to access the outside of the wall and apply the waterproofing material. In this case, the only option is to waterproof that wall from the inside of the structure. After prepping the concrete to ensure the surface is clean and ready to receive waterproofing material, a waterproofing coating is applied to the wall to prevent any water from entering the structure.
We recently posted an article about how to prep elevator pits for waterproofing, which has relevant instructions for prepping a negative-side (interior) surface for waterproofing. You can access that information here.
Here are W. R. MEADOWS products that support your positive-side waterproofing:
Here are our negative-side waterproofing products.
Request More Information