All across the world, one of the most common methods of covering a house is with metal roofing, and the same is true here in Connecticut and New York. Practical and enduring, metal roofs can be as traditional as an old farmhouse or as contemporary as a Main-Street coffee house. While the metal itself can last for over a hundred years, the protective coating must be periodically maintained. There are many products and methods available for painting metal roofs, depending on your specific situation.
Painting Metal Roofs
Painting metal roofs presents two main difficulties to the home or business owner. First, the correct metal paint products must be selected, which requires specialized knowledge. Secondly, the project must be set up carefully to provide a safe working environment on the roof, which is always a hazardous location.
The best way to get a good metal paint product for your specific roof is to talk to a specialist at a quality paint store (not a big-box home improvement center). Describe the kind of metal you have (cold-rolled or galvanized) and whether it has been previously been painted. If you are not sure, take a few digital photos and show them to a knowledgeable clerk.
Here are a few general pointers:
- To keep the traditional shiny-metal look, a fibrous aluminum coating is a great product. It also helps to seal small leaks.
- Elastomeric paints are extremely flexible, which makes them a good choice for metal roofs, since they are prone to significant expansion and contraction with temperature change. These also can bridge small cracks and holes to keep out water.
- If the roof was previously painted and has no bare metal, a latex/acrylic coating will provide nice color and good protection.
- Urethane-resin acrylic paints have the best binding power, and will keep their color and protective value for a long time.
- If your current roof is galvanized, do not paint over it with an alkyd-based paint, as this will react with the zinc on the metal, and the coating will peel off very quickly.
Preparing your Metal Roof
To work safely on the roof, use ladders and scaffolding as much as possible, and be careful to set them up on a firm, level surface. If you must walk on the roof, be sure to secure yourself with a rope and harness, and don’t work alone. The safest and most efficient method of working on a roof is with a motorized lift with a telescoping arm. These can be rented from many locations.
Once you are safely set up, you need to clean the roof thoroughly. A power-washer alone is not sufficient to remove the residue and create a good painting surface. Use a mixture of TSP and water, and mix in a bit of bleach if there is mildew present. Use a long-handled scrub brush to wash the roof, paying special attention to areas of rust. Allow it to dry, and then you’re ready to start painting!
If you have any bare metal, it will be necessary to prime before you paint. Depending on your topcoat product, you may need to prime anyways. Read your product labels carefully, and be sure to ask your paint store representative if you need a primer.
When you begin painting metal, plan your work so that you will not need to walk or drag ropes and hoses across the area you have painted. A long-handled roller brush is a good method for large, flat surfaces like a roof, but spraying will provide a more professional-looking finish. After the first coat, allow it to dry thoroughly. You will probably want to plan on two coats, since this will provide better color consistency and a longer-lasting finish. Some products specify that they only need one coat, and in that case, follow the manufacturer’s instructions.
If you have any questions, submit your comment below or ask us on twitter or Facebook. You can also learn more about exterior painting and maintenance through our blog. If you are considering professional assistance, read these tips before hiring a painting contractor.