Exposed concrete floors are much sought after for their contemporary look, and increasingly found in lofts, condos and retail spaces. If you think one would look good in your home, you’re not alone—it’s definitely a décor option to consider!
Resin coatings 2.0
These days, there are several ways of highlighting exposed concrete. The products that offer the greatest resistance and practicality are thermosetting resins, which have two components, namely, a resin and a hardener. There are two types: epoxy and polyaspartic.
Resins are in a pure state (100% solids) and contain no solvents, which means they don’t release harmful fumes, as VOCs (volatile organic compounds) do. This makes them a particularly good choice for indoor use.
Resins are industrial products that can be ordered from retailers and applicator companies. It’s best to entrust the job of applying them to professionals, however: first of all because of the difficulties involved in application, but also because the warranty coverage won’t be the same if you do the work yourself.
This article deals with epoxy coatings. To learn about polyaspartic resin, another product with attractive properties, read our Tips & Tricks instalment on coatings for concrete garage floors.
Epoxy: steps for application
Before applying an epoxy coating over a concrete floor, the applicator must:
- Polish the concrete lightly using a grinder with a diamond blade
Two full passes are made over the entire concrete surface to remove the whitish film—which is not very resistant—as well as any impurities. Polishing also increases the porosity of the material to ensure that the coating adheres properly. Lastly, it brings out the texture of the concrete: aggregates of varying shapes and hues.
- Apply the primer coat, which can be coloured
There are many possible looks, from simple to elaborate. By colouring with metallic pigments, for example, all kinds of visual effects can be achieved: an illusion of depth, marble veins, “lava flows,” etc. Depending on their skills, professional applicators can, in principle, offer you a lot of options.
- Apply one or more clear epoxy top coats
A clear finish leaves the concrete aggregates visible, resulting in a terrazzo effect, which is very attractive in many kinds of rooms.
Concrete in the basement
If you are thinking of concrete for your basement floor, it may or may not be a good idea, depending on how old your house is.
In a recent property, applying a floor finish directly to concrete is certainly feasible, as long as the slab beneath is protected by a vapour barrier and rigid insulation. Among other things, using concrete as a floor covering allows you to maximize ceiling height: you won’t lose any space by applying extra layers.
In an older house, it may not be a good idea. Humidity issues, for example, can thwart your plans. Why? Because coverings sealed with 100% epoxy solids form a vapour barrier; they can’t be applied to a floor slab that is subject to pressure from groundwater. That pressure could lift the finish and ruin the look of the floor covering. A moisture test is therefore a must.
What to do if a test confirms a moisture problem
There are several possible actions to correct a problem of excess humidity with a basement slab, but this work can be very expensive. An alternative is to live with the moisture and build a subfloor that allows it to dissipate into the ambient air. You can then install a floor finish that handles varying humidity levels well.
To keep an exposed concrete floor in spite of a humidity issue, you can apply thin coats of a water-based epoxy sealant, which is much less viscous than 100%-solids resins. The sealant will penetrate the pores of the concrete, rather than forming a film that would be likely to lift under water pressure—on the contrary, it will help reduce that pressure. This type of sealant, however, needs refresher coats more often than solid finishes do.
A durable, versatile solution
It’s no accident that concrete has become so popular as a floor finish. Products available today bring out its natural qualities and make for a durable, easy-maintenance surface that fits well with many décor styles and can be applied in a wide range of colours.
This waterproof surface is perfect in laundry rooms, bathrooms, entryways and even kitchens. In short, it’s a rock-solid floor-covering option!