Metal Roof Coatings – Everyday Questions About Today’s Roof Systems



Roof coatings are helpful today in maintaining all kinds of roof substrates. Not only do they extend the durability of any roof, they also provide energy savings in warmer climes. A renewable weather barrier over the regular roof acts as the first line of defense against elements.

Here are some everyday questions about roof coatings that home owners have – and their answers from industry leading specialists.

Why are roof coatings used with metal roofs?

The coating of metal roofing systems degrades over time. A maintenance layer of roof coating can restore them and extend their life. Galvanic corrosion is a major problem with un-coated metal roofing, creating the demand for corrosion inhibiting roof coatings. Reflective roof coatings can provide an added benefit of a cool roof which helps cut down on energy costs.

Roof coatings can be aesthetic and have weatherproofing effects. As they come in various colors, roof coatings can add to the visual appeal of your roof. At the same time, they guard your roof against moisture and prevent structural weakening from damp. Roof coatings may successfully put off the need for replacing leaky metal roof panels.

Metal roofs have the unique feature of expanding and cooling with temperature shifts. Roof coatings address this and are useful for retrofit or roof repair projects. By also preventing rusting and becoming a ‘sacrificial layer’ for the elements to act upon, they add value to any metal roof. Another common use of roof coatings is for waterproofing.

What influences the demand for metal roof coatings in today’s market?

In a cost conscious and environment friendly world of green buildings, the energy savings provided by roof coatings make them desirable to home owners. Throw in the environmental advantages of roof coatings and together they become a powerful incentive for adoption. State government programs that highlight these advantages have added to the growing popularity of metal roof coatings.

Reflective coatings can deflect heat and keep buildings cooler even without air conditioning. As factory coated metal sheets develop wear and tear around 10 to 15 years after they are first installed, many metal roofs applied in the 1990s are becoming due for renovation or replacement. Roof coatings are an effective solution, being cost effective and reflective into the bargain.

Metal roof coatings like acrylic, rubberized aluminum, SBS white coatings and polyurethane materials all offer a greater diversity of choices, appealing to a wider audience of home owners and roofing contractors.

What new roof coatings are popular?

The latest roof coatings are zinc rich metal and roof primers. These enhance the adhesion of finish coatings, and at the same time they cover rust and prevent sheets from rusting further.

Newer materials like the poly-urea and fluoro-polymer formulations are in the news more often. These have good elongation and greater tensile strength as compared to other roof coatings. However the time-tested acrylic and polyurethane products are still the best selling ones.

Another new technology that’s gaining traction is based on fluoropolymer roof coatings like Kynar. These materials are supposed to provide higher reflectivity, durability and are easier to clean. As building codes change to require cooler roofing, the use of energy efficient roof coatings is only set to grow even further.

What kinds of metal roofs are ideal for roof coating?

All metal roofs – the factory applied coated ones as well as un-coated metal roofing systems – are ideal for roof coating restoration. This includes steel, galvanized metal and aluminum systems. The key test is one of adhesion, to make sure the coating will ‘stick’. Some slick finishes like Kynar-500 won’t let acrylic coating adhere well. Metal roofing needs to be clean and sound before you can apply roof coating to it.

Four products are used in roof coatings – a cleaner, a primer, a flashing grade sealant and a finish coating. Using the appropriate combination for a specific kind of roof will deliver the best results. Including a foam layer to absorb the expansion and contraction can work even better.

Does the color of roof coatings affect roof temperature?

White roof coatings reflect the most light and heat. They also emit heat better than others. Many other “cool colors” are rated by the CRRC (Cool Roof Rating Council), and any top quality roof coating reflects all radiation and will emit most of the little heat that it does absorb. Thus lighter colored roof coatings can lower cooling costs on air conditioning.

What other problems exist with roof coatings?

Roofs attract dirt and so a white (or light colored) roof coating will lose some reflectivity as it dulls. In time, up to 80% of their reflecting power may be lost, the speed of decline depending upon weather conditions. But even at these low levels, roof coatings work better than typical dark colored roofs without coating.

Roof coating system manufacturers typically offer 10 year warranties. Designing the coating process and planning the roof well can minimize dirt accumulation as well. Regularly cleaning the roof of accumulated debris can also help. Less sticky roofs are less likely to hold on to dirt.

Roofs with irregular projections may pose a challenge with roof coatings. Spray application methods may help work around this. Coating can be applied using brushes, rollers, or spray rigs. Seams must be managed manually.

In many different ways roof coatings deliver extra value to your roofing system. Lowering energy consumption, protecting metal and adding durability, waterproofing, and repelling moisture are the most obvious. Adding longevity to your roof and being an effective temporary bridge until the time for roof replacement are other benefits of roof coatings. But be sure to consult with a specialist about which kind of coatings are best for your home.



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