CONTRIBUTORS | CONCRETE
Learning the Language of Sealants
SCOTT BARNES
Choosing the right concrete coating depends on the project
I
n our business we often hear phrases that use the word “seal” in relation to concrete decks. Coming from property owners, condo board members and property managers, the word has so many meanings and far-reaching implications that we usually stop the conversation right there and start asking questions to narrow down what it is that they want to achieve. Ask 10 people what “sealing the concrete” means to them and you will likely get 11 answers! As a rule of thumb, “sealing” to a licensed concrete coating contractor means either installing a waterproof coating, decorative coating or penetrating coating, or maybe a combination of coatings depending on the structure. To further complicate things, each of these coating types has sub-categories, grouped by material, application and finished appearance. There are even some waterproofing coatings that still “breathe.” Understanding the language used in concrete coatings also is important so both client and contractor are on the same page. Words you might hear or come across in a proposal or in researching coatings include elastomeric, solvent-based, water-based, cementitious, penetrating, on-grade, above-grade or elevated, primer coat, base coat, wear coat, texture coat, top coat and clear coat. As an estimator, I usually start by asking whether the structure to be coated is elevated or on-grade? This is key, and depending on the answers to the next few questions there could be multiple options. Or maybe just one. My next question usually is about traffic—is it vehicular or pedestrian?
At this point I am narrowing down the options available and starting to formulate additional questions that will ultimately give me one or two recommendations. Next question: Are you trying to protect the concrete or change its appearance, or both? Next I ask the client what they want to see as a finished project. What do they expect the coating to do or solve? How long do they expect it to last, and what is their expected level of maintenance? I usually get asked about coatings for four basic types of structures: parking decks, pool decks, walkways/lanais and planters. Parking decks and walkways are usually the easiest to provide recommendations for, because by their very nature they are “elevated” and should be waterproofed. Typically, that waterproofing type is the multi-layer elastomeric coating. They start with a primer
22 BUILDING MANAGEMENT HAWAII | JULY 2020
and base coat to seal the concrete in a non-breathable “rubber” coating. The rubber coating of course needs to be protected so additional layers of material are added on top of the primer and base coat. For vehicles, it is usually two wear coats in driving lanes and a single coat in parking stalls. Elevated deck waterproofing usually involves coating the whole concrete slab on every elevated floor, but there are some parking decks that only receive the coating at the parking stalls that are open to the environment (rain). This is less costly than coating the whole structure, but in my opinion does not fully consider wind-swept water being moved into the driving lanes, causing wheel spin and sliding by cars and pedestrians moving across wet floors. In cases like this, maybe the parking stalls should be coated with an elastomeric, and critical known areas of pedestrian traffic or vehicle turns
