Most people get sold on the idea of metal over other roofing materials because it is said to have an average life of 50 years or more. The truth is that before 50 years go past you will begin having problems with your roof. This can happen almost immediately if your roof was installed incorrectly or you might last five, ten or even twenty years before you find problems that need fixing.
Visual Problems Vs Structural Or Performance Issues
One of the biggest problems is rust but its not likely to be the first problem that you will experience. The first problem is likely to be leaks caused by the small gaskets under each fastener. When the sun hits the roof the gaskets will deteriorate. This makes them loose and you will have leaks. Other problems can be cause by improper surface prep before the metal was applied or things like valley flashing and gaskets failing. Most of these problems are not dramatically visual but they cause leaks and failures that need to be repaired as soon as they are noticed.
Rust On New Metal Roofing Is A Visual Problem That Will Only Get Worse
Rust and Rust Stains on a brand new roof are very common but they are not structural. They are a result of poor installations. Often when you are installing metal roofing you will have small scratches and chips through the painted surface. These areas have to be addressed immediately during install and should not even wait a few days because bare metal starts to rust within hours and a rain will make it worse.
Additionally the way a contractor cuts the metal can cause small chips of metal to broadcast all over the surface which will rust and cause stains and streaking. The best way to deal with this is to cut your metal on the ground as much as possible and clean up any metal chips and dust from cutting. Sheers are a better choice than a grinder with a cutting disk or a nibbler cutter which both will broadcast small steel fragments across your painted roof surface. Use a leaf blower and follow up with a pressure washer to remove all of it before completing the job.
If you find you have rust staining from either of these problems you can often treat the painted surface with a weak phosphoric acid based wash to remove the staining just like you would use in your bathtub or toilet.
Preparing A Rusted Steel Roof For Painting
Later in your roof’s life you will likely come to the point where the surface coating is beginning to fail and the look of the rust is making you consider painting it. There are a lot of products that are used for refreshing a metal roof’s appearance but the first thing you need to do is neutralize the rust that already exists. Just like removing surface rust stains a Phosphoric Acid Based Rust Converter is best for this procedure.
First inspect the roof and make sure that the metal has not been rusted so bad that it needs to be replaced. Second if the scale is very bad you might need to use a wire brush, or a twisted wire cup brush on a grinder to remove large buildup. You should also remove any rubberized or asphalt material that might have been used for patching in the past and then inspect your screws and gaskets and replace those that need replacing.
Next you will want to wash the surface clean with a mild soap and pressure washer. Be very careful while doing this and you do not need to be right up on top of the work as you clean. You can use extended rods for your pressure cleaner that let you reach onto a roof or that let you reach over a peak and get all the way down to the soffits.
Once the grease is removed and the surface is prepped you can apply your rust converter solution with a pump or electric sprayer. For best results you want this solution to stay on the roof overnight to react with the rust. You will then need to rinse off the solution before you can paint.
Painting Your Rusted Metal Roof
There are a number of products that you can use to resurface your steel roofing. An enamel based paint such as heavy equipment paint or rustolium is available by the gallon and is inexpensive. If you want a specific color of roof other than silver, white, black then you will need to use one of those products. Normally one gallon will cover about a 10 x 10 foot area but read your directions. Normally a single application is made unless you are getting bleed through and color changes that require a second coat. YOU DO NOT APPLY THIS WITH A BRUSH YOU NEED A PROFESSIONAL SPRAYER TO APPLY IT.
Other options are acrylic / asphalt emulsion based materials that have the claim to fill in any pinholes and thicken the surface. Those claims are often not realistic but many people find these products work well. The only problem you will have is that cracking of the material away from the surface can often allow water to penetrate between the coating and the roofing metal. If you are going to use a material like this I would strongly recommend that you start with a painted surface as described above and then apply these filler/sealer products so that bare metal is not what the sealer adheres to.
Final Note
Metal Roofing is becoming very popular not just on barns, outbuildings, commercial buildings but now it is very popular on residential buildings. Metal is available in a variety of shapes that replicate the look of other materials like Clay Tile, Slate or other textures that do fool the eye a bit from the ground. Steel Roofing also provides a great barrier in areas that see forest fires or brush fires. It may not prevent extreme damage but it could give you more time to react and save your home. That with the relatively inexpensive cost and long life makes it a great solution.
Make sure that you inspect your roof yearly from the ground with binoculars and also from within your attic to look for wet / dark stains that may indicate fastener gasket failure or other problems.
Finally painting your own roof is dangerous so don’t do it if you have any apprehension. And I mean any apprehension. The cost you will pay is much less than having to deal with an injury that could last you a lifetime or worse. If you find you are getting price quotes that just aren’t sane then keep looking because a little rust isn’t an immediate problem if the roof is structurally sound and not leaking.