Resin for outdoor concrete

Exterior concrete surfaces require proper protection to ensure they last for years. Concrete resin is a material that not only protects concrete from damage but also adds aesthetic appeal.

What is concrete resin?

Concrete resin is a specialized material used to protect and finish concrete surfaces. It is a synthetic substance based on polymers such as epoxies, polyurethanes, and polyureas

Why is it worth using resin for concrete outdoors?

Outdoor concrete surfaces are exposed to weather conditions such as rain, snow, frost, and UV radiation. Resin protects concrete against: 

• water ingress,
• scratches and mechanical damage, 
• cracking due to changing temperatures,
• dirt and stains, 
• various types of chemicals.

Additionally, the resin-coated surface looks modern and aesthetically pleasing, which undoubtedly increases the visual value of the investment and also affects the entire surrounding space.

Properties of resin for external use

Resins used outdoors have a number of properties that make them an ideal choice: 

• UV resistance – prevents the surface from yellowing and fading. Epoxy resin is an exception to this, and therefore it is not recommended to leave it outdoors without covering it with another, UV-resistant resin.
• Resistance to temperature fluctuations – polyurea and polyurethane resins are fully resistant to temperature fluctuations, which are quite common in the Polish climate, both throughout the day and year. Coatings based on these resins do not crack or deform due to frost or heat.
• Waterproofing – resin coatings for concrete protect it from moisture ingress, preventing corrosion and mold growth. Furthermore, water entering the pores of concrete, expanding and then turning into ice during frosty weather, can lead to concrete damage. Therefore, it's crucial to protect concrete, for example, with resin coatings, to extend its lifespan.
• Resistance to mechanical damage – resin materials are highly resistant to loads and intensive use. They originate from industry, where they have been repeatedly subjected to various load tests. Therefore, they can also be successfully used in areas not strictly related to industry, such as parking lots, garages, driveways, and ramps.
• Aesthetics – the ability to choose from a variety of colors and finishes (matte, gloss, and anti-slip), as well as additives such as decorative flakes, liquid granite, or colored quartz sand, not only enhances the floor's protection, but also creates a visually pleasing user experience, adding value to the entire investment.

Types of resins for outdoor concrete

Depending on your needs and conditions, you can choose different types of resins:

Epoxy resin

Ideal for surfaces exposed to intense stress. It is characterized by high durability and chemical resistance, but may be less resistant to UV radiation. Therefore, for outdoor applications, it is most often recommended to cover it with another type of resin, such as polyurethane, which is UV-resistant.

Polyurethane resin

More flexible than epoxy resin and resistant to fluctuating temperatures, it's ideal for outdoor applications where surfaces are exposed to sunlight. These materials are typically tintable, allowing you to achieve any color on a vehicle, parking lot, or ramp. Polyurethane resin is an excellent choice for protecting outdoor concrete from late spring to early fall, as it requires positive temperatures, typically around +10°C, for proper application.

Polyaspartic resin

Also known as polyurea resin, it creates a quick-drying and highly durable surface. It's suitable for areas requiring rapid completion of work. Furthermore, projects using this type of material can be completed at relatively low temperatures, close to 0°C. In such conditions, the polyurea resin cures without any problems. It's worth remembering that polyurea coatings are also highly flexible, making them ideal for various types of ramps, balconies, and other outdoor areas where the building or substrate is subject to some stress.

Advantages of using resin for concrete outdoors 

• Long lifespan – resin surfaces can last for many years without the need for frequent repairs. Of course, it's worth periodically inspecting resin coatings to check for wear, cracks, or other damage. Nevertheless, resin floors on concrete typically last from several to a dozen years without the need for repairs.
• Aesthetic appearance – the ability to match the color and finish to the surrounding style. Creating colorful, interesting coatings using resins is usually very simple, yet significantly impacts the overall perception of the surroundings. Using decorative flakes and other additives is inexpensive and creates a unique effect on concrete floors.
• Weather resistance – the perfect solution for harsh weather conditions. Whether you need to protect your concrete floor from moisture, temperature changes, or UV rays, concrete resins can handle them all! When choosing a resin for outdoor use, consider polyurethane and polyurea resins.
• Anti-slip properties – resin floors on concrete can create a smooth, and therefore slippery, coating. This can be compared to smooth tiles. This effect can be easily mitigated by using anti-slip additives, such as anti-slip resin microbeads or quartz sand. Depending on the level of wear, anti-slip properties ranging from R10 to even R13 can be achieved!
• Concrete protection – resins for concrete, in addition to their weather resistance, also offer excellent resistance to mechanical damage and chemicals. This protects the concrete floor from abrasion, for example. If it's known in advance that specialized chemicals will be used in a given location, it's worth checking the resin manufacturers' technical data sheets when selecting a resin to ensure the best resistance to the selected chemicals.

How to apply resin to concrete outdoors?

Resin application requires proper substrate preparation, as well as several other steps to ensure the entire process is effective. The basic steps to take are:

• Surface preparation: The surface to which the resin will be applied should be clean and free of grease, dust, and dirt. If present, degrease the floor using, for example, concrete degreasers. Furthermore, it is recommended to vacuum the floor before applying resin to concrete, including outdoors, to remove dust particles and other contaminants that cannot be removed by hand. At this stage, it is also necessary to fill any imperfections in the concrete surface to ensure a satisfactory final visual effect. Sanding the concrete surface is also recommended to improve resin adhesion.
• Priming: To ensure proper adhesion for the resin layer, it is recommended to prime the concrete first. With outdoor concrete, the moisture content of the concrete is never certain. Most epoxy-based resin primers for concrete require a 4% moisture content, which is difficult to achieve in the Polish climate due to high humidity for much of the year and a relatively low number of sunny days. Therefore, an epoxy primer for damp concrete, such as Neopox Primer WS, is recommended. It will not only provide adequate adhesion for the resin but also handle the moisture trapped within the concrete. A properly primed substrate should have a uniform gloss. If any dull spots appear, this indicates increased absorbency in that particular area and requires the application of another layer of primer.
• Resin application: Apply the first layer of resin using a roller or trowel, depending on whether the product is thin or thick. Once the first layer has dried, subsequent layers can be applied, depending on your needs and the type of product. When applying resin outdoors, it is important to maintain minimum humidity and temperatures of the air and substrate to ensure proper application and subsequent curing of the resin coating on concrete.
• Finishing: In some cases, it's worth applying an additional topcoat, such as a non-slip or protective layer of decorative flakes or liquid granite. For the floor to be fully functional, you need to wait the appropriate time specified by the manufacturer in the technical data sheet of each product, which ranges from 24 hours to up to 7 days in the case of epoxies or polyurethanes.

Care and maintenance of outdoor resin surfaces

To ensure that the resin surface continues to function as long as possible: 

• It is worth cleaning it regularly from dirt using mild detergents. 
• Avoid using aggressive chemicals that may damage the resin structure. 
• Check the condition of the coating – if you notice any cracks or other damage, it is recommended to repair them quickly.

The most common problems with outdoor resin

Although concrete resin is a permanent solution, there are some issues that can arise:

• Cracks – resulting from improper preparation of the substrate or subsequent use.
• Yellowing – may occur with resins that are not sufficiently resistant to UV radiation, such as epoxy resins or aromatic polyurethanes.
• Mechanical damage – due to very intensive use or the use of the wrong type of resin.
  To avoid problems, it's best to follow the manufacturer's recommendations and use professional services during application.