Do I Need to Prime a Tin Roof Before Painting?

Why Use a Primer?

• When it comes to beginning any painting project, a primer is an essential, beneficial tool. Naturally, painting a tin roof is no exception. Primers help create a smooth, even surface, helping the paint properly adhere to the surface. On tin roofs, primers can also act as a sealant, helping provide an additional layer of protection for the metal surface. Using the proper primer can also help seal the metal, keeping rain, wind, ice and other elements from causing corrosion over time.

Choosing a Primer

• The Paint and Coatings Resource Center recommends using a zinc chromate primer for your tin roof. Zinc chromate primers are treated with additives that help prevent corrosion on metal surfaces, including tin roofing. According to Color Server, zinc chromate primers were originally developed by the airline industry in the 1940s. They also contain toxic elements that will help break down any organic material, such as leaves, plants and moss that land on the roof. Zinc chromate primers may be difficult to find at a standard home improvement store, but should be available at any store that supplies materials to metal roofers. In a pinch, any exterior primer for metal surfaces may be substituted; however, it may not be as protective as the zinc chromate variety.

Preparing the Roof

• While selecting the correct primer is an essential step when properly painting the roof, it is not the first step. Before applying the new primer and the paint, the roof needs to be thoroughly cleaned. Tim Carter, of the Ask the Builder website, recommends using a mixture of common household soap and water to clean the roof. For stubborn dirt and grime, a power washer may be helpful. Use a wire brush to help remove any flaking paint and stubborn stains. Before priming and painting, also ensure that any corroded areas or small holes are patched.

Tips and Tricks

• Reprime and repaint your tin roof every three to five years. This will help improve the longevity of the roof, ensuring that you will not need a replacement for decades. In addition to using a zinc chromate or metal-appropriate primer, it is essential to use paint appropriate for metal roofs. Carefully apply the primer using a paint roller or a brush. Work in long, even strokes working with the grain of the metal. Always allow the previous coat to dry completely before applying your next coat. Apply at least one coat of primer before painting the roof. Carter recommends working on overcast, dry days to help keep the roof cool and avoid the risk of sun damage.