When it comes to buildings, a common misconception is that the material of the building is enough to help it stand up to the elements.
There is some truth in that logic, as the building’s material does determine how hardy it inherently is, as well as how long it can last.
However, even the toughest materials aren’t immune to wear and tear.
Just look at the rocks by the beach. Even the hardest rocks will, over time, be worn out by saltwater and develop holes.
Whether it’s metal, concrete, or glass, the sun, rain, debris, and temperature changes will eventually wear it out — if you don’t protect it, that is.
Steel can rust, concrete can crack, and glass can be scratched. But with the right paints and sealants, those will become worries of the past.
To find out which are the right paints and sealants to use for each surface, we consulted Anthony Meyers, the founder of Renewed Walls Painting.
These are the protectants to use for each material.
Metals
The main enemies of metals are corrosion and oxidation. Needless to say, a metal beam that rusts is extremely dangerous, so using the proper paints and coatings to keep that from happening is a top priority for building metals.
Carbon Steel
Among all metals, carbon steel is the most commonly used for building structures.
The main threat to carbon steel is rust, and to safeguard against that, you’ll either have to be using galvanized steel, or you’ll have to apply a zinc-rich primer over your non-galvanized carbon steel, usually followed by an epoxy or polyurethane topcoat.
Galvanized steel itself will resist rust, so if it’s galvanized steel that you’re using, there won’t be a need for additional protection, except in very aggressive environments.
Stainless Steel
Stainless steel is known for its toughness, and it’s much less prone to corrosion than most other metals.
Nonetheless, even stainless steel will still corrode in harsher environments, like coastal areas or regions with heavy pollution.
Generally, for regular use, stainless steel, like galvanized carbon steel, will actually have no issue with corrosion.
But for those above-mentioned harsher environments, you’ll need an additional protective coating like a fluoropolymer or acrylic coating.
This coating will act as a barrier against salt, chemicals, and other pollutants, significantly bringing down the chances of corrosion.
Smother finishes, like polished or electropolished finishes, also leave fewer crevices for salt to cling to, helping further reduce the chances of corrosion.
Aluminum
Aluminum, like stainless steel, is mainly at risk of localized pitting corrosion.
Aluminum actually naturally forms a thin protective oxide layer that protects it from external elements, but as always, in salty or acidic environments, that layer won’t be enough.
The main additional protection methods are anodizing, powder coating, and polyurethane coatings.
For most buildings, anodizing usually suffices, but its color shades are limited to metallic shades, so if you’re looking for other colors, you’ll want to go with a powder coating or polyurethane coating instead.
The main difference between those two coatings is that powder coatings are usually more robust and also provide UV resistance, while polyurethane paints are used either when powder coatings aren’t feasible, or when you want a glossy finish.
Concrete
Concrete may seem sturdy on the surface, but it’s actually quite porous.
This wouldn’t be an issue for normal water, but when the water contains salt, the salt can corrode the steel reinforcement inside concrete.
Not all rainwater will contain salt, if the building is near a coastal area, tiny seawater droplets are constantly being thrown into the air, and that’s how they reach nearby concrete surfaces.
Or if roads were treated with de-icing salts, these salts will find their way to concrete surfaces, whether it’s through the melted ice or car tires going over then and throwing them around.
This is made worse by the fact that carbon dioxide will react with the lime in concrete and weaken its alkalinity. In simple terms, that means it becomes more prone to rust.
Even putting rust aside, since concrete is porous, as freeze-thaw cycles cause expansion and contractions, they add to the stress and wear the concrete out more quickly.
To prevent all these from happening, the best way is to keep the water out in the first place, while ensuring any that gets inside can escape easily.
This is usually achieved with acrylic or elastomeric paints.
For tougher environments, epoxy or polyurethane coatings may be used instead for stronger protection.
Brick & Masonry
Brick is extremely porous, even more so than concrete, which means the freeze-thaw effects are even more severe.
Again, as with concrete, the most effective solution is one that keeps water out while letting any that get in escape easily.
This means breathable water repellants like siloxane or silane sealers.
You’ll notice that we’re using different protectants, and that’s because concrete tends to require more heavy-duty protection, since they’re usually used for important supporting structures like columns and pillars.
In contrast, brick and masonry tend to be used for facades and walls, which isn’t to say that protection isn’t important, but it’s just more crucial that concrete structures suffer as little wear and tear as possible, seeing as they directly affect the building’s stability and safety.
Another reason why the protectants are different is that the ones used for concrete tend to affect the surface’s appearance and detract from its natural look. We don’t want that with brick, since brick’s intended aesthetic is usually natural and timeless.
In certain cases, when more heavy-duty protection is needed, such as for data centers, elastomeric paint is still used, even though it changes the appearance of the masonry. This is because in such cases, performance matters more than appearance.
Conclusion: Don’t Skip the Protection
It’s easy to tell yourself that using a heavy-duty material is enough, and that it should be able to last for a long time, even without additional protective coatings.
However, this is a huge mistake, because it’s a surefire way to shave off many years from your building’s lifespan.
In the worst cases, it could result in complete collapse when there’s structural damage, but even in the best cases, you’re looking at a facade that wears out much quicker and brings down the aesthetic appeal of your building.
So spend a little more upfront and have a painting contractor apply the necessary protectants. You’ll save yourself much more on future replacement and repair costs.
