Roof Coatings: Things to know before making a decision

Your roof is one of the most important assets of your building, responsible for keeping weather out and taking major abuse from mother nature.  Many building owners, home owners, building managers, and building maintenance staff are looking at roof coatings as a cost-effective way to maintain and preserve their roofs while minimizing the impact on their residents, tenants, or living conditions. Although roof coatings are an affordable solution, many times they are not applied correctly or in the right circumstance.  So how do you know if a roof coating is the right application for your roof?

Let’s first look at some of the roof coating systems available today.  One of the most well-known and commonly used systems are fabric-reinforced acrylic coating systems.  These systems consist of multiple layers of acrylic coating material with fabric embedded within the coating system for reinforcement. Acrylic coating systems are very cost -effective and have life expectancies anywhere from 5 to 30 years depending on the system design and amount of material applied.  Another well known coating system that has been around for a long time is Urethane Coating.  These coatings are typically applied in several layers (base layers and top layer) and do not require full reinforcement like acrylic coatings do.  Similar to acrylics, urethane coatings have life expectancies anywhere from 5 years to 25 years depending on the quality and type of urethane used.  One of the up and coming players in the coating world is silicone coating.  Rapidly growing in popularity, silicone coatings are typically single-component, single-layer coatings that do not require full reinforcement throughout the system.  Silicone coatings have life spans of 10 to 50+ years depending on the manufacturer and the thickness of coating being applied.

So, back to the question of how do you know if a coating is the right solution for your roof? With so many choices it can be very challenging to determine which solution is best based on cost, application, use, and life expectancy.  The most important factor to evaluate when looking at a roof coating is substrate condition, i.e. what is the coating going over.  While every coating has its pros and cons, all coatings are only successful if they are put over a proper substrate.   Far too often the condition of the existing roof or substrate is overlooked for factors such as cost, time, and impact to tenants or residents.

The most important factor to look at when assessing a roof coating as a solution is the presence of moisture within the existing material. If there is evidence of moisture within the roof system or active leaks occurring, there is the potential to trap moisture under the coating.   Although some coating systems have the ability to breath (allow small amounts of moisture to pass through them) the coatings will almost always fail as a result of moisture within the substrate. This is also a key exclusion in all manufacturer’s warranties.  It is imperative to remove all moisture from a roof surface prior to the application of a coating.  Determination of moisture within a roof can be made in several ways using equipment specifically designed for moisture detection.  Hiring a professional consulting or testing agency properly trained to perform these tests or mandating that the contractor or manufacturer perform a moisture survey prior to commencing with the work are some of the ways to know whether or not you will be faced with this problem.

If a roof has significant evidence of deterioration such as blistering, cracking, separation of existing roofing, or soft spots, these all need to be properly addressed prior to applying a coating.  Ways to solve these problems include pre-treating conditions with reinforcement methods as recommended by a roof consultant or manufacturer, repairing the damaged areas, or replacing the areas if the extent of damage/deterioration is too significant.

The third factor to assess when evaluating roof coatings is the presence of ponding water.   Most manufacturers exclude ponding water conditions from their warranties, so it is important to eliminate ponding water from the roof or apply a coating suitable for ponding water.  Acrylic coatings typically do not hold up in ponding water conditions and failures at ponding water is one of the most common issues noted with acrylic coatings.  Silicone and Urethane coatings are less susceptible to failures from ponding water and do not have ponding water exclusions in their warranties. If ponding water exists on a roof, the owner should make sure that all necessary steps are taken to eliminate the ponding water condition first and if that is not feasible, select a coating system that can tolerate the conditions present on the roof.

In conclusion, there are many roof systems out there and each system has its appropriate applications.  It is important to select the correct roof system for the application and conditions the roof system will face.  Need help determining which solution is best for you?  Contact a professional roof consultant today and ask these specific questions prior to making any decisions.


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