An exterior paint problem many homeowners encounter is chipping from gutters and downspouts. It’s pretty annoying … actually. The rest of the paint in your house appears to be aging normally, but your gutters and downspouts spill paint like a river birch sheds its bark on a bad day.
Gutter stripping is often common on galvanized metal gutters.
The problem exists because the wrong paint was used for the first coat on the gutters and downspouts. The most common mistake I’ve seen is applying oil-based paint directly to bare galvanized metal. It will not last more than a few years.
My testing over the past 26 years points to oil-based paint being applied to bare metal as the main culprit. Ninety percent of the time, painters working for builders made this crucial mistake.
I also found that most oil-based primers do not adhere properly to galvanized metal. I have found that a cement based primer will adhere very well to galvanized gutters. Porter Paints has a product called Porter Guard Galvanized Metal Primer 290. It contains cement and does a great job of bonding in the long term.
If you’re reading this article and having trouble stripping your gutters, there’s good news and bad news.
Okay, here’s the bad news. Be prepared to strip all the gutters bare and start over, or prepare to service the gutters fairly regularly. Scraping and priming will not restore the bond in areas that have not yet been peeled off. Priming and topcoating all gutters at this point will not restore the bond. It cannot penetrate through existing paint and cause faulty paint underneath to reattach to galvanized metal. You will continue to develop flaking on these metal surfaces over time.
The good news is that you can remove what is peeling now and prepare the bare metal with the primer I mentioned earlier. It will stop the flaking in those areas.
Here are some important steps to take.
1. You will first need to remove peeling paint from downspouts and gutters with a wire brush or scraper. A wire wheel on a drill works well too.
2. Clean the sanded area with a good quality solvent to remove any oil from the surface. Clean metal areas with a thick layer of solvent and allow it to evaporate completely.
3. After the solvent has evaporated, apply the cement-based metal primer paint directly to the bare galvanized metal spots. Allow the primer to dry according to the manufacturer’s recommendations and then apply latex paint or oil-based paint as a top coat.
It is possible to use latex paint instead of primer.
If all the oils are removed from the bare metal, you can even recoat the metal with latex paint instead of a primer if you wish. Over the years, I have found that if the surface has been properly cleaned, plain latex paint will adhere to bare galvanized metal much better than oil-based paint.
Complete the project with premium house paint. Use two coats in extreme cases.