How Weather Affects Painting
In industrial projects, latex paint is rarely used. Urethane or epoxy-based coatings are 2 or 3- component products. They are “chemically-cured” products, and if the temperature is not controlled properly, the coating will not properly cure. Containing the environment — the temperature, humidity, etc. — within specs is not as easy as you may think!
Most people don’t understand that on an industrial project, where we are typically coating concrete and/or steel, the substrate temperature (the temperature of the steel, for example) is always different from the ambient temperature (or what the thermostat on the wall shows you.) Concrete and steel retain heat and cold differently than, say, drywall. Steel in direct sunlight can easily be 40 degrees hotter than ambient temps in the summer months.
So to get the environment right, we will often build scaffolding, around the project, and then shrink-wrap the scaffolding, resulting in a complete bubble — a custom-built, onsite isolation booth. We then add indirect heat (no direct flame source), dehumidifiers, and explosion-proof ventilation fans, to control the project environment, despite changes in the outside weather. That is key to getting the job done correctly without impacting the schedule.
Take the example of a project with cooling towers on the side of a building. (Cooling towers use falling water to provide cooler temperatures in a variety of applications.) We build a scaffold around the structural steel tower and shrink-wrap it, creating an isolation booth. Using abrasive blasting, we then take the tower down to the bare metal, in preparation for painting it. During that process, we must keep humidity at a minimum, in order to prevent rusting. We have to do all this while the client is using the cooling tower — without interrupting his production. Controlling temperature and humidity in this situation is a real challenge. Our containments must be weather-proof and rugged as this environment mirrors that of consistent rain.
All of this goes far beyond what the average person may imagine when they think about painting and the weather.