Metal roofs should be painted at regular intervals to protect the metal surface and prevent rust from forming, without wasting too much time introducing the subject and answering the question as quickly as possible, yes, corrugated roofs can be painted with a roller, special rollers are available to suit different corrugated roof configurations.
In the research I did for the subject I directly asked two of the painters I always use for general jobs, and they both affirmed that you can paint a corrugated roof with a roller, although they prefer to do it with a paint spray gun, painting a corrugated ceiling with a spray gun has its drawbacks as well.
Obviously painting a corrugated roof is not as easy a task as it sounds, especially if you are not a professional painter, I must say, there is also some confusion with the term “corrugated metal roofing”, this concept can refer to any type of metal that is formed by grooves and ridges, but in reality, in the professional field they refer to corrugated roofing that has a corrugated profile in the shape of an “S”.
Specially shaped rollers for corrugated metal roofs
The complication of painting corrugated ceilings is precisely the undulations generated by the material, apart from the fact that these ceilings are usually found in sometimes steep slopes, whatever the type of corrugated ceiling you need to paint with rollers, there are special corrugated rollers that adapt to the corrugation patterns of the ceiling.
The Roller is made of polyester foam in corrugated form, resists all types of paints, is washable and reusable, and is specifically designed for painting corrugated metal surfaces.
This roller usually has a width of 14″ (36 cm), this width is sufficient to paint the corrugated surfaces of a metal roof with relative ease, and I say this because I once witnessed how a corrugated metal roof of a small house was painted with a 6″ brush, which seemed to be an extremely tedious and titanic task.
The brush can be used in a common way to make touch-ups on the roof, but painting large surfaces of a corrugated roof with a simple brush is a task almost comparable to climbing Mount Everest.
In case the shape of the corrugated roller is not suitable to adapt to the corrugations of the metal roof you intend to paint, don’t worry, there are other types of rollers specifically designed for painting corrugated and ribbed surfaces, such as the spherical roller.
The spherical roller may not have the same surface coverage as the corrugated roller, but the speed with which you can paint with this roller makes up for the rest, plus, its spherical shape adapts to any corrugation or channel created in the surface of the metal roof.
The spherical roller can paint any corrugated metal roof surface with almost no problem, but for corrugated roofs with channels and slots, there are also special rollers up to 14″ that adapts perfectly to the shape of the roof.
There are metal roofs that instead of being corrugated have trapezoid shapes, and the spaces between the “corrugations” are much wider than the roofs with “S” shaped corrugations, for these roofs there is a special type of roller as well.
Is it better to paint a corrugated metal roof with a roller or a spray gun?
I mentioned at the beginning of the topic that for the research I conducted I asked several professional painters about it, both told me that they preferred to paint a corrugated roof with a spray gun than with a roller, and this is precisely the fundamental difference in the comparison.
Painting a corrugated metal roof may be better with a roller for people who are not professional painters, although it may not seem like it, it takes some expertise to paint, the use of the spray gun for painting requires skilled labor, the gun needs to be cleaned before and after each job.
There is also the fact that for spray painting in open-air spaces, such as a roof, for example, the amount of breeze that may be present will make the work very difficult, dispersing the paint in the direction of the wind and therefore the performance of the paint would not be the same.
The roller has the disadvantage of being slower than the spray gun, also, if the spray gun is used in optimal conditions and by people, a thicker and more consistent coat of paint can be obtained.
What type of paint is suitable for painting a corrugated metal roof?
The most suitable paint on metal is usually latex paint or acrylic paint, In most cases, if the metal roof has many pores, it is necessary to use a sealer before applying the acrylic paint, this will provide a better finish and further protect the material from possible corrosion in the future.
What to consider before painting a corrugated metal roof?
Ideally, plan the job in a warm-weather season, where the roof is dry and it is hot outside. Always keep in mind that in summer, when the outside temperature is extremely high, the metal roof can heat up to such an extent that it is impossible to repaint it, and waiting for the sun to go down will deprive you of the light needed to do the job.
Proper pretreatment is also important, you need a surface to which the paint will adhere. When the paint peels off, any paint residue from the past must be removed.
After the roof has been pretreated, a primer and, of course, the later paint should be applied, as the pretreated surface is relatively sensitive to the effects of the weather. You can use a normal standard primer or a special primer. Alternatively, you can use a protective varnish for metal that does not require a primer.
How to paint corrugated metal? step-by-step instructions
Corrugated metal roofs must be thoroughly cleaned and free of stuck-on dirt before painting, this is essential. If rust has formed, it is removed with a steel brush and brushed off thoroughly. Final cleaning is done with an alkaline agent.
If there is already a coat of paint on the corrugated metal roof, you should perform a scratch test to check its durability. The edge of a coin or the tip of a wrench is used to scratch the surface. If a trace forms on the roof surface without peeling off, you can paint over the paint without removing it. It is advisable to perform this scratch test in several places.
With painter’s fleece or abrasives from 300 grit and up, the surface of the sheet metal is roughened evenly.
Non-galvanized corrugated metal roofs are coated with a zinc-containing primer according to the manufacturer’s instructions.
5. Painting or coating
Depending on your choice, the paint is applied with a brush, roller, or spraying device. There should be no direct sunlight during application. After one hour of drying, most coating agents do not affect the sun’s rays.