A roof coating may be something you’ve heard about as a building owner but know little about how it works. You may ask, “Do I need it?”. You may also have questions pertaining to its cost and life expectancy. Without spending a great deal of time researching the subject, you need answers. That’s why we’ve taken it upon ourselves to create this mini guide to roof coatings for you to read.
Ideal Roof for Coating
Before getting started, it’s important to know if the roof can be coated? Knowing which roof styles are suitable for coating helps you determine if your commercial building is a good candidate for the service. You will find a detailed description of the ideal roof for coating below.
Nearly every type of roof can be treated with some type of roof coating. Metal, single-ply, modified bitumen, spray polyurethane, and built-up roof (BUR) systems respond well to being coated. The only types of roof surfaces that don’t do well with roof coatings are ballasted and gravel surfaced membranes unless they are treated in advance to being coated.
Preparation
Preparation is key when applying a roof coating, the coating will only be as good as the surface its applied to. First things first, you want to make sure that all testing & surveys (e.g. Moisture Survey, Adhesion Test, etc.) have been performed and passed before making the decision to move forward with a roof coating.
Ensure all repairs have been made in accordance with the practices provided in the NRCA manuals. Be sure to build up any areas that are susceptible to ponding (low points in the surface). The easiest way to address this is by adding an additional ply of membrane to the area to raise it.
Once all the surveying, testing, and repairs have been completed then the roof can proceed to prepping roof to be coated. First the contractor must thoroughly clean the roof. Next, they put down a primer so that a roof coating can adhere better to the substrate. Finally, they apply the coating with either a sprayer, brush or roller for even distribution of the substance. Please refer to the manufactures materials data sheet and stick to the application rate that is recommended. Be sure to allow the proper cure time before applying additional coats.
Types of Coating
There are many types of coating. Determining the right type for your roof depends on what you’re hoping to do with the treatment. Getting to know the advantages of each allows you to make an informed decision about which to choose for your commercial property.
The three types of roof coatings available are Acrylic, Polyurethane, and Silicone. Each has its advantages. For example, acrylic is inexpensive, ideal for all roof types, and holds up well in most climates.
Polyurethane coating come in two types, aromatic and aliphatic, and withstand impact well. The first variety is inexpensive but does not hold up as well under UV rays. The second variety costs more but retains its color better and handles the hot sun better.
Silicone doesn’t become brittle or harden in extreme temperatures. Humidity doesn’t negatively affect the coating. Applying it removes the need for a primer in many cases.
Life Expectancy and Typical Cost vs. Replacement
Among the many benefits coating provides is an increased life expectancy for an existing roof. Rather than wear down as quickly due to age or the elements, roofs with coating last longer. The advantage of this is that you’re not out the money that it takes to completely replace the roof.
To get a sense of the value of the service, it’s important to understand what coating costs and how long it lasts compared to replacing the roof and how long it lasts. A roof coating has a life expectancy of five to ten years according to the manufacturer’s guarantee. A roof can last seven to fifty years depending on the materials used to create it, the geographic location of the building, and how well it has been maintained by the building owner.
