If you've ever tried to make paint stick to a tin roof, you know just how frustrating it can be. Although it's natural for even the most quality paint job to eventually deteriorate, most of the time when paint begins to peel early, it's either because the painter applied the wrong kind of paint or used improper preparation techniques.
If you're planning to paint a brand new, raw tin roof, you don't need to do much preparation work. However, if the old roof already has a coat of paint on it, you'll need to prepare the surface for the fresh coat of paint. Make sure to use a putty knife to scrape and scratch away all loose, pealing paint. Once you've removed the largest chunks, smooth the surface flat with course sandpaper. Without proper preparation, even the best paint will have trouble adhering, so take your time and thoroughly prepare the surface.
Many people think the reason their paint job fails is because they applied a cheaper brand of paint. Usually, however, the reason a paint job doesn't last is because the painter failed to use a primer. Surfaces such as metal and raw wood require at least one coat of primer before you paint them. A tin roof is no different. Make sure to apply a thin coat of primer and allow it to dry thoroughly before you paint. Oil-based primer is the best choice, but certain types of latex primer can also be used. Read the label to make sure the latex primer is treated for exterior use on metal.
Oil-based paint is the preferred choice. Although, there are certain brands of latex paint available for use on exterior metal surfaces, they don't tend to last as long as oil-based paints. Also, oil-based paint tends to go on a lot smoother than latex paint, which can leave unattractive brush strokes even after it dries.
A simple paint brush is all you need to paint a tin roof. Use a latex brush for latex paints and an oil-based brush for oil-based paints, otherwise, the brush will quickly ruin. For larger areas, you can use a spray rig for faster application.
As with any paint project, proper surface preparation is the key to painting a tin roof. Although most people prefer to spend as little as possible on home improvement projects, a little extra money spent on a quality primer can go a long way toward making your paint job last.