Choosing between PU and epoxy resin flooring systems depends on the environment, explains Chris Dobbie.
01 April 2019 | Chris Dobbie
The two main types of resin floors are polyurethanes (PU) and epoxies, and each has different properties suited to particular uses. Choosing the wrong solution could result in costly repairs or even complete floor failure.
Although both are called resins, epoxy and PU floors are not the same. They share similarities, such as being two-component systems (resin and hardener) that, when brought together, undergo a stoichiometric curing process to form a solid layer.
During curing, the main components of the resin mixture link together, which can vary drastically in timescale depending on the specific components, ambient temperature and on-site conditions. In both cases this results in a seamless, impervious coating that can be applied in large quantities.
But they are two very different types of materials. The main difference is the molecular structure, which affects how it fuses together during the curing process. There are multiple types of components that can be used, which will slightly vary the result. However, the essential point to note is that PUs have a higher cross-linked density than epoxies, making them hardier.
PU for strength
PU systems are durable and resilient against heavy footfall, physical impacts, extreme temperatures and corrosive chemicals, making them well suited to industrial facilities.
They could even bear the burden of a fully loaded hand pallet truck weighing more than a tonne. Fortunately, PU is thicker and heavier than epoxies, and can absorb higher impacts and thermal shocks.
PU systems can tolerate intense heat; some are resistant to 120°C (epoxies can only handle up to 65°C). They also offer superior chemical resistance, making them popular in the food and beverage industry, with large quantities of corrosive acids and by-products.
They can also stand up to chemicals from organic acids, sugar and malt, as well as caustic and powerful cleaning agents.
Different types of PU
Just to confuse issues further, there are different types of PU systems. There are full PU 'liquid-vinyl-type' floors, which are great for creating soft surfaces underfoot because of the elastic nature of PU.
More common are PU deck coatings for car parks and PU concrete systems, which are often found in industrial facilities as they are the most failure-resistant type of resin flooring available - able to withstand punishing impacts, extreme temperatures, heavy loads and harsh chemicals.
PU systems can also be customised with anti-slip aggregates and anti-bacterial additives, and are able to deal with rising moisture. However, they're not very pretty or colour stable, unless covered with an aliphatic coating.
Epoxies for aesthetics
It might seem like polyurethanes are superior, but they are less versatile than epoxies and lack high-quality aesthetics.
Epoxies can be adapted for a variety of environments and come in many colours, styles, effects and decorative options.
There may be a specific challenge or requirement that warrants choosing a polyurethane flooring, but for the most part, an epoxy floor will be up to standard - while offering bright and glossy tones, glittering light-reflective surfaces or multi-toned swirling shades.
This gives designers the creativity to install unique floors that convey the interior design scheme. This is a good way to represent a brand identity, aesthetic or infuse the environment with a desired vibe.
Epoxies are the go-to floor for large-scale commercial venues such as shopping centres and airports, non-heavy-duty industrial spaces and customer-facing processing zones that need to look good and be functional.
The choice between epoxy and PU systems will depend on the needs and stresses of your building. The decision is largely based on aesthetics and versatility versus resilience and durability.
Chris Dobbie is UK sales director at Flowcrete