Understanding the Differences between Epoxy, PMMA, PUMA, Polyurethane, and Polyurea Coatings for Parking Decks

Traffic-bearing membranes are an excellent solution when it comes to protecting your parking deck from external elements like unpredictable weather conditions. Since the objective of installing these structures is to protect your investment, it’s important to consider all necessary factors and make the right decision for your needs.

Parking decks are often exposed to harsh elements and endure a great deal of abrasion caused by constant vehicular and foot traffic. Traffic-bearing membranes act as a reinforced structural support system. They need to be durable enough to handle heavyweight objects, while maintaining a certain level of flexibility to prevent cracking and structural failure.

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The challenge is finding a happy medium and striking the right balance between rigidity and flexibility—hard membranes are inflexible, while pliable membranes can’t withstand abrasion.

What is the best solution? To begin, we will look at the reasons why deck protection is necessary as well as the pros and cons of Epoxy, PMMA, PUMA, Polyurethane, and Polyurea coating systems.

Why Protect Your Parking Deck?

In colder climates like ours, traffic and parking decks are subjected to extremes in temperature and environment. Moisture, containing chlorides from de-icing products, will track into garages on tires, or hitch a ride as built up ice within the wheel wells, and ultimately will soak into the concrete surface. These chlorides then travel to the embedded steel reinforcement via the pores and cracks in the concrete. Once these chlorides reach the steel, they cause expansive corrosion, resulting in damage and deterioration of the structure.

In addition to being the delivery system for chlorides, water also causes other issues in colder temperatures. The water in the concrete decks will expand and contract during freeze/thaw cycles. There is a solution to this—air entrainment—however, garages continue to be constructed without sufficient air entrainment, leading to the premature degradation of the concrete as freezing & thawing water destroys it from the inside out.

Because parking structures are exposed to the elements, they are more susceptible than other types of building structures to deterioration caused by contaminants, moisture, and temperature changes. Even the best built parking decks need some help to battle this onslaught of negative forces.

The Options

Today, there are many options for traffic-bearing coating systems. The main goals of using a deck coating are to:

  • Improve aesthetics
  • Protect the concrete surface
  • Waterproofing (to provide a leak-free system, not a water resistant one)

The following are some of the coating options available with the pros and cons of each.

Epoxy Broadcast Systems

Pros: These systems have been used for many years, are easy to apply, economical, and provide concrete surface protection. They are durable and by using different aggregate (flint, aluminum oxide, etc.) can offer a heavy-duty type wearing surface that can handle severe traffic such as loading docks, service ramps etc.

Low-viscosity epoxies fill the pores present in concrete creating a barrier to chloride contaminated water. Additionally, they can be injected into cracks to structurally repair them. Epoxies can also limit vapour transmission, although this must be done carefully to ensure moisture is not locked within the deck. Epoxy systems offer a good, moderately priced, solution for parking structures that are starting to show some distress, both in treating deterioration and preventing further water damage.

Cons: Epoxy coatings are not known for their flexibility and are not capable of crack bridging, so they are not considered to be a true waterproofing solution when used on their own. They will not adhere to wet or soiled fractures and are not good with moving cracks. Where a traffic deck is continuously exposed to sunlight, epoxies will degrade due to UV radiation.

Polymethyl Methacrylate (PMMA)

Pros: PMMAs are in the acrylic family and are very durable, colour stable, and chemically resistant. They cure fairly rapidly (60 mins), can be placed at low temperatures, and can accommodate traffic within a few hours.

Cons: For enclosed parking structures, or other areas where fumes might be a problem, offensive odours might prove prohibitive. Like the epoxy healer/sealers they also fall short in wet or soiled fractures, to which they will not adhere, and in moving cracks that are likely to re-fracture. Additionally, you need to play chemist on-site mixing a number of components.

Polyurethane Methacrylate (PUMA)

Pros: PUMA membrane is similar to Polymethyl methacrylate (PMMA), although the material offers more elongation. The membrane does provide a material that can bridge cracks (thanks to the polyurethane component), though in some applications reinforcing fabric is required. PUMA has rapid cure time (30-45 mins) and can be quickly opened to traffic.

Cons: Odour is an issue, similar to the PMMAs. Like the PMMA systems, you have to measure and mix a number of different components on site. In certain cases, reinforcing fabric is required.

Elastomeric Polyurethanes

Pros: In parking garages where there is continuous movement of the deck—vibration, cracking, expansion and contraction due to weather changes, etc.—or there is more advanced damage, a polyurethane traffic-bearing membrane may be one of the only options that can handle the ongoing degradation.

Polyurethane coats the surface and creates a barrier to lock out moisture and chlorides. Most elastomeric polyurethane systems have two coats: a base coat that provides the waterproofing protection, and a topcoat, which protects the base membrane and provides skid resistance. The end result is a much improved, attractive looking parking deck that is easy to clean.

Cons: Elastomeric polyurethane membranes’ assets are also their downsides. Because they are highly flexible, polyurethane systems in high-wear areas like ramps and turn areas may require additional layers of coating to help with durability. More rigid polyurethane varieties have been designed to better withstand abrasive forces of heavy traffic.

The use of hybrid systems with a more flexible polyurethane membrane base coat, with a more durable polyurethane topcoat, will provide the required durability. When you also add an aggregate, this will increase the durability of the system even further.

Polyurea

Pros: Polyurea traffic coating systems are vapour-permeable, waterproof, and can easily be applied by spray. They form a seamless, monolithic, flexible, and waterproof protective coating.

Polyurea coatings dry to the touch in seconds and are walkable within a few minutes forming an outstandingly tough, flexible, and chemically resistant surface. These coatings waterproof their substrate and have the ability to extend by 300% to over 600%, thereby enabling them to bridge hairline cracks on concrete surfaces.

Polyurea is 100% solid with no solvents, meaning no emissions and no VOCs, hence an extremely environmentally friendly coating. There is no odour. Due to their exceptional properties, Polyurea spray coatings are now being used extensively for waterproofing, corrosion protection, containment, linings to tanks and structures, protection of concrete joins, and structures, etc.

This surface treatment combines the best of all the above options. Although abrasion-defiant, it is flexible enough to bridge moving cracks, locking out all moisture, chlorides and other contaminants, and cures quickly (six seconds). It is 100% environmentally friendly, has no odour, and available in a wide variety of colours to match any decor.

Cons: Requires the use of specialized spray equipment and applicators will require specialized application training.

Why Choose IMC Distributors?

IMC Distributors is proud to be the exclusive distributor for ISOMAT products in Canada. We’re also the master distributor for Lab Surface in Ontario and we distribute Protocol Concrete Protection Products that are designed with Innercrete technology. Our mission is to provide the latest product advancements and the most efficient installation methods. Contact us today to learn more!