How to paint a metal roof

Metal roof painting and repainting is no small task; even the pros can make mistakes if they forget a step or accidentally start painting as if it were a normal surface such as wood or concrete. Metal roofs need special paints and special care. Learning how to paint metal roofs, what to buy, and what to avoid can’t be completely explained in one article, but you can get a good idea as to what the best ways are to approach a project of this skill level and expertise. Even if you wind up hiring a contractor, it’s still a good idea to arm yourself with a basic understanding of what’s going to be involved. Let these tips guide you to a more informed purchase.

Paint isn’t “just paint”

You cannot use any of your normal house paints to paint a metal roof. Metal roofing paints need to be made specifically for the conditions that they are going to encounter. The paint must be able to withstand boiling temperatures from the sun’s rays, as well as be fire-proof, water-proof, and able to fend off any pest invasions. You will notice many options if you visit your local home supply store, like elastomeric, acrylic, and oil-based paints. You will need to know whether your roof is galvanized to choose the correct paint that will hold up the best for your roof.

A good example of paint that will protect your home, as well as make it look nice, is elastomeric paint. These specialized paints offer great protection from the sun’s rays because of their inherent reflective properties. These qualify as “green” energy efficient paints. The paint is also a bit thicker and offers great waterproof protection, too.

Proper Technique and Maintenance

No matter how high quality your paint is, if it isn’t applied correctly and carefully maintained, it will not prove to be a worthwhile investment. One big example of unknowingly sabotaging your investment is by neglecting to seal the roof first before applying the metal paint. Use of sealant isn’t optional, so never let a contractor tell you otherwise. Without it you will risk your paint coming right off, whether that is in a few months or a few years. Your paint will be unsalvageable if it is applied without sealant. Just as with pairing your paint to match a galvanized or non-galvanized roof, the sealant must be compatible with the type of paint in order to be effective.

After successfully painting your metal roof and everything looks great, it is your job to keep it that way. Yes, the best metal roof paints will withstand lots of abuse from the outside elements, but that doesn’t mean it can clean itself and deflect all the debris that can pile up over time. Preferably, you should be removing any pile-ups of dead leaves and branches every week in the fall. If your house doesn’t get a great deal of large debris, then giving it a good wash twice a year is adequate to maintain the paint’s integrity.

How to Prepare your Roof

If you’re one of the lucky ones that has a metal roof with no previous history of painting, then you can skip this section. Metal roofs are rarely in a pristine, ready-to-go condition that is just waiting to be painted, so if your roof has paint already, you’ll need to estimate how much it’s going to cost to remove it. It can be expensive to repaint metal roofs. The more layers of paint, the less likely it’s going to be worth it, financially, over replacing it altogether. You don’t want to go into this project with a half-baked cleanup plan that just involves scraping and sanding as much as you can before adding a new coat of paint.

If your roof just has one previous coat of oil-based paint, then you should be able to get most of it removed through some hard work, provided you have the proper tools. You’ll need to start with large scrapers, down to sanding tools, and finally wire brushes. After that, you can move onto pressure washing and attending to any rusty spots. If there’s a lot of rusty areas, this could really compromise your new coat of paint, so err on the side of caution.

As for other types of metal paints, acrylic paints take more time to remove, but otherwise apply the same rules as the above instructions. Asphalt coatings are trouble, and it is often not worth the investment of buying special metal paint due to the simple fact that old paint will never come off completely. It is also worth noting that asphalt can hide issues with a roof’s integrity and it is worth considering replacing it if you really want to improve the quality and value of your home.

DIY Application Tips

Again, these tips are useful to know even if you don’t plan on painting your roof personally. Proper technique and smart application can save you lots of money and future headaches. Below are a few things that often get overlooked.

Don’t start painting under direct sunlight. Just because the paint is graded to be able to stand up to temperatures of 110F doesn’t mean that you can expect it to adhere to the roof properly upon application. You want to stay below 80F, if you can, so the surface of a metal roof can effectively have the chance to set properly. Otherwise you’ll have lots of bubbles, ripples, and little imperfections that can compromise the effectiveness of a roof, as well as its visual uniformity. As for colder temperatures, try not to go below 50F, as once the surface starts getting closer to the freezing point, it starts to affect the way the paint adheres to the metal/sealant because of the extended drying time.

Now you have a basic understanding of just how delicate and nuanced metal roof paints can be. Keep these things in mind when you are planning your own project or when you are researching candidates to tackle it for you.