Over time and under the right circumstances, gutter rust can form and destroy your gutter system. Gutter rust can occur on all components of the gutter system. Such as the corner miters, the downspouts, the gutter trough, the end caps, etc… Basically any aluminum component is susceptible to the same gutter rust or corrosion.
Once gutters begin to rust, there usually is no going back. If rust holes have started to form then the rust is spreading through the inside of the metal and will continue to spread.
Aluminum is a rust proof material. That is one of the reasons it is the most popular guttering material, aside from being very light and affordable. However, over time rust can form on this rust proof material. It does take extreme circumstances to make this happen.
In this article we will explain gutter rust/corrosion on aluminum guttering and any possible solutions to fix. Other gutter materials like galvanized steel, pvc, and/or copper do not apply to this article. Galvanized steel guttering rust all over and copper gutter forms a patina that is similar to rust. Lastly, pvc guttering does not rust at all because it is plastic.
THIS ARTICLE IS 100% ABOUT ALUMINUM GUTTER ONLY!
Causes of Gutter Rust or Corrosion
In the spring season most trees don’t drop a lot of leaves. They do however drop flowers, seed pods, and pollen. Some tree pollen is very acidic and dangerous to your gutters if left unchecked. Acidic tree pollen can eat the coating right off the aluminum, leaving the gutter material vulnerable to rust and corrosion.
When tree pollen drops onto your home, it flushes through your gutter system fairly easily because pollen is very very small particles. As long as there are no clogs the pollen washes away just like dirt. When pollen falls into your gutters and then there is no rain for weeks , is when the damage starts to happen.
Spring is generally a rainy season so the tree pollen will flush away every time it rains. It’s when there is no rain for weeks, right in the middle of pollen season, that your gutters could be at risk. All it takes is a little bit of moisture, like fog or dew, to start the process.
If you know pollen is stacking up on your roof/gutters and there is no rain in the forecast, you can wash off your roof and flush your gutters just by using a garden hose from the ground. Give your roof a nice thorough spraying so that every shingle looks wet. This will ensure you’ve flushed all the pollen off the roof and through the gutters, and will prevent any acidic pollen from eating your aluminum gutters.
Reactions With Other Metals
All metals are prone to different types of corrosion such as Galvanic Corrosion. Galvanic Corrosion is when two dissimilar metals come in contact through a conductor (water) and they react to each other which causes gutter rust/corrosion.
The basic explanation of this when dealing with gutters, is that copper can’t touch aluminum or steel. Copper guttering needs all copper components and hardware. Aluminum guttering needs stainless steel hardware. Any other metal will start a reaction that will cause the hardware and surround surface area to rust or corrode.
Extreme temperature fluctuations can also wear down your gutters much faster than it would normally occur. When temperatures make extreme changes, over and over, it starts to break down the structure of the aluminum. For example, let’s say it gets up to 90 degrees by day, but down to 40 degrees at night, this is what we would call extreme temperature fluctuations.
These types of issues are mostly common to mountain regions or coastal regions. Also, there is no way to prevent this from happening besides not living in these regions.
General Gutter Neglect
Gutter neglect can mean a variety of things, but what we are talking about here is when you don’t clean your gutters for a couple years. Neglected gutters will clog up from debris and eventually fill with water and decomposing plant material. When the water can’t drain properly through the gutter system, a pool of swampy water is stuck there.
It’s important to remember that clogged gutters aren’t going to rust on their own. Something needs to break down the outside layer of the aluminum to allow the rust to infiltrate the material. Such as acidic pollen or reactions with other metals.
However, neglecting your gutters will speed up the gutter rust and/or gutter corrosion process. If rust is forming and there is standing water present, that rust is going to spread at a much faster rate.
Sand Gutter Rust
Gutter rust can be slowed down and sometimes stopped if caught at an early enough stage and treated properly. You can sometimes use sandpaper to sand off the surface rust that is forming on the gutters.
You can use sand paper or even a wire brush to clean the rust off of the aluminum surface. Be sure that you get every last speck or color of rust off of there. When you are finished with the sanding process, it is very important that you now paint the gutter with a primer. Sanding of the aluminum removes the protective outside layer and leaves the rest very vulnerable to rust. You must seal this off with the water proof primer.
It is important to remember that if rust holes have started to form, meaning you can see through the hole or water leaks from the hole, than it is too late to be sanded. If you can see holes than there are more holes forming throughout. Think of it like swiss cheese. Once the rust bypasses the coating and infiltrates the inner layer of the aluminum, it spreads like wild fire.
Remove Rusted Gutter Section
Another short term solution to gutter rust is to cut out the entire rusted section of gutter and replace it with a new section of gutter. Let’s say that you have a long run of gutter (50 ft) and you can’t really afford to replace the entire 50 foot section. Perhaps cutting out a couple feet and replacing is the better option.
We don’t really suggest this unless it’s an emergency for a couple reasons. One is that when you join two or more sections of gutter together, you have gutter seams. These seams are prone to leaks and will need to be resealed every few years.
If you are going to cut out a rusted section of gutter, we would suggest making sure your cut is a couple feet away from the rust or corrosion. Rust permeates the aluminum and spreads so if you can see rust on the outside, it is safe to assume that it is much more spread on the inside of the aluminum.
Caulk Gutter Rust Holes
Another temporary solution you can try, is to caulk your rust holes. This one isn’t rocket science to explain, you basically use a waterproof sealant/caulk to cover the entire hole. Once it is dry and cures properly, it will prevent the water from leaking through the hole.
The important thing to remember with caulking rust holes, is that the rust is going to continue to expand and eventually outgrow the caulk. Therefore, using caulk on any rust hole is a very temporary fix. Moreover, if you have rust pin holes forming than your aluminum gutter has been infiltrated with rust and more holes are going to randomly appear and also need to be sealed. Once this starts happening, replacing the gutter is the only option.
Galvalume Guttering Material
Regions that are close to salt water generally see aluminum gutter material rust and corrode much faster than in a non coastal area. The salty air breaks down aluminum and causes corrosion. In these areas Galvalume Gutter is substituted for Aluminum Gutter because it is more resistant to gutter rust and corrosion. However, it cost about double the price as aluminum so it is a very expensive fix. We would only suggest this if you have had many problems with gutter rust and nothing else seems to help.
Gutter rust is rare, but it does happen and it is something that you should keep an eye out for. If you can find the rust in it’s early stages you should be able to sand it down and primer to prolong the life of the gutter. Lastly, if you have a lot of rust appearing you may need to replace those sections.
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