What Is Positive and Negative Waterproofing?

There are a number of methods that are used to waterproof a structure from the inside and outside, which are often determined on a case-by-case basis depending on the dynamics, design, and circumstances of the structure. Positive side and negative side waterproofing are two of the waterproofing solutions in the construction industry.

What’s the difference between these two? In this article, we will explain and explore both methods, so that you can make an informed decision when determining which one is the most appropriate for your specific needs.

What Is Waterproofing?

Before diving into the specific types of waterproofing, it’s important to understand what it means to waterproof a structure. As you probably already know, waterproofing simply means to prevent water from penetrating a surface or substrate and causing severe damages such as cracking or weakened structural integrity. 

Waterproofing is the process of applying a certain coating or protective barrier on top of an existing object or surface to make it impervious to water damage and permeation. 

Positive and Negative Waterproofing

What Are the Differences between Positive Side vs. Negative Side Waterproofing?

The waterproofing method required for your residential or commercial structure depends on a number of factors including the climate, building materials used, and the purpose of the structure itself. There’s where positive side and negative side waterproofing solutions come into play. Both serve very distinct purposes.

Positive Side Waterproofing

Positive side waterproofing is the process of applying a waterproofing agent to the exterior of a structure or surface to prevent moisture from getting in. The objective with this process is to sufficiently protect the interior of the structure from being exposed to excessive moisture, which could lead to structural failures, moisture, and mildew development.

Positive side waterproofing is also meant to effectively prevent flooding and other related water damages.

Negative Side Waterproofing

On the opposite end of the spectrum, negative side waterproofing is the process of applying a waterproofing agent or coating on the interior of a structure, surface, or foundation. Similar to positive waterproofing, negative waterproofing also works to create a strong barrier to prevent external moisture from seeping into an otherwise dry space and causing structural damages.

Negative side waterproofing is commonly used for structures located in high-impact areas that are susceptible to heavy rain, flooding, or other types of inclement weather conditions. Structures that benefit from negative side waterproofing solutions include tunnels, townhomes, condos, apartments, semi-detached homes, or any structures that are attached to other structures.

For example, if you live in a townhome, it makes sense to apply negative waterproofing along the shared walls of each individual domicile to prevent inter-residential water leaks in the event of flooding in one of the units.

What Are the Advantages of Positive and Negative Waterproofing?

Positive and negative waterproofing solutions each have their own unique sets of advantages that come in handy in different ways.

One of the main advantages of positive waterproofing is that it protects the structure against external water damage, cracks, and leaks. Not only does this help extend the lifespan and functionality of the substrate, but it also keeps the structure looking and operating like new a lot longer. Plus, positive waterproofing also provides a layer of insulation which helps protect the structure from damages related to freeze-thaw cycles or exposure to corrosive chemicals.

But there’s also a glaring and unavoidable downside to positive waterproofing. Since the system can only be applied to the exterior of the structure, it’s impossible to access it from the inside when repairs, maintenance, or reapplications are needed. Whenever positive waterproofing requires maintenance of any kind, the overlying surface (e.g., dirt, grass, landscaping, hardscapes) needs to be removed so that the appropriate repairs can be made. Not only does this create a lot of extra work in preparation for even the simplest and smallest repairs, but it can also significantly run up the cost of maintenance.

On the other hand, negative side waterproofing is applied to the interior or dry side of the substrate. Negative side waterproofing is applied to prevent water exfiltration while also adding an extra layer of structural protection and strength. This method prevents water from entering into an occupied space such as a house or storefront.

The only blatant shortcoming of negative side waterproofing is that it doesn’t necessarily prevent water from making direct contact with the substrate. Once the substrate has been compromised, the structural integrity of the entire building could be put at risk for water damage or infiltration.

To be able to withstand hydrostatic pressure, negative side waterproofing applications typically use epoxy injections and cementitious coatings. The main advantage of a negative side waterproofing application is the undeniable easy access compared to positive side waterproofing. Since the application site is usually inside the structure in question, it’s a lot easier to get to it if it requires repairs, maintenance, or reapplication from time to time.

When to Use Positive and Negative Side Waterproofing

Foundation waterproofing in North America can be a little tricky mostly due to the constantly fluctuating climate conditions. When used in tandem with one another, positive and negative waterproofing solutions are extremely durable, resilient, and versatile. They complement each other perfectly by picking up each other’s slack and, ultimately, strengthen and improve the performance of the other.

Waterproofing Products from IMC Distributors

As the exclusive partner of ISOMAT waterproofing products in Canada, IMC Distributors is proud to offer high-performance positive and negative waterproofing solutions that are specially formulated to effectively work for a variety of applications and protect against external environmental elements such as extreme temperatures, inclement weather conditions, and more.

At IMC, we offer a wide range of waterproofing solutions, products, and materials that can help protect your structure from the inside and outside. We also offer training and certifications for our products and their applications.

Check out our extensive inventory of waterproofing products here. For more information about our waterproofing solutions or to place an order, contact us today.

Karli Logan is the Owner and President of IMC Distributors which is the exclusive partner of Nukote Coating Systems in Canada. With a B.Sc and M.Sc, as well as a demonstrated history of working across a number of industries, she has a passion to drive significant gains and benefits for IMC’s clients.