How to Clean Metal Roofing

To get the longest life out of your metal roofing, you must establish and stick to a schedule of regular maintenance. There are several means available for cleaning the metal roofing, like pressure washers and wire brushes. Cleaning becomes all the more important for the houses with metal roofing that lies in an area susceptible to mold and mildew. These tips will help you approach cleaning your metal roof the right way so that you don't end up causing damage.

Step 1 — Assess the Scope of the Project

First of all, assess the overall condition of the surface. It requires a lot of effort to prep and clean of an old metal roof because of the corrosion that build up over time and the several layers paint. Although an old roof that has been properly maintained requires less labor to prep and clean, there will still be some corrosion and old paint that needs to be removed. On the other hand, cleaning a new roof doesn’t need as much preparation or effort.

Step 2 — Ensure Your Safety

Make all the arrangements necessary to ensure you will be safe throughout the cleaning process. Do so before even stepping onto the roof. Be sure that you can reach every single part of the roof with ease. If possible, tie yourself with a safety rope and harness.

Step 3 — Scrape Paint and Corrosion

Avoid scraping the paint unless you are sure that you won’t damage the roof. If you really need to scrape the excess paint or the peeling paint, do not to use any metal instruments to do so. You can use a wire brush instead. If the wire brush fails to do the job, then, and only then, you can use a flat-blade putty knife. This will take care of most paint-scraping jobs, but proceed gently, as you do not want to scrape and scuff the actual metal surface.

Step 4 — Clean the Mold and Mildew

Mix 1/2 cup of tri-sodium phosphate (TSP) in a gallon of water in a bucket. If needed, increase the amount to cover a larger area while keeping the same proportion of water and TSP. TSP is available in most paint or home improvement stores. Now, take a soft brush, dip it into the solution, and start scrubbing the areas affected by mold and mildew.

Repeat this process until the area is free of mold and mildew. Then rinse the area with water thoroughly.

Inspect the roof after drying and repeat this step as many times as needed. Remember, this step requires a lot of patience.

Step 5 — Clean the Dirt and Debris

Now clean the dirt and debris with the help of a pressure washer. Always start this process from the topmost part of the surface. This will help in carrying away the dirt and debris.

You can also use a mild detergent solution in place of plain water if your roof is in particular need of a more intense wash. However, keep the concentration of the detergent at its minimum. As you spray, keep the distance of the pressure washer nozzle uniform across the roof. This will avoid getting too close and damaging the roof, as well as being too far away and not cleaning thoroughly enough.

Repeat the process if necessary.

Step 6 — Touch up Paint as Needed

After drying of the roof, you can repaint the areas with scraped-off paint and corrosion. Before using the paint, apply some primer, which will act as a deterrent against further corrosion. Don’t apply paint until the primer gets dry enough to facilitate a smoother application. After you've primed and painted your roof, you may also want to consider applying a paint sealer.