Discussion of Painting Rooftops from a Washington, DC Area Contractor
Usually we look at the roof as the aspect of an exterior that we have to work our designs around. Depending on the type of construction, and whether the building is urban or suburban, roofing is usually constructed of tar, asphalt, or composite shingle. Usually these materials are neutral in color, with shades ranging from white and gray to red, brown, or black.
Depending on what climate you live in, your rooftops may be darker or lighter. Dark roofs absorb heat, while light roofs reflect it. When it’s cold out, and you want to maximize your passive solar absorption, the dark roof is an asset. In the heat of summer, however, or in tropical climates, the extra heat absorbed by a dark roof can cause an extra strain on your energy bill. You can see local roof styles reflecting the needs of the climates where they’re built: tropical areas tend to have lighter roofs, and cool northern climates tend to have darker roofs. In general, however, it is easier to get a dark roof than a light roof – and easier to benefit from a light roof than a dark one. Many of the materials used to produce roofing are dark-colored (especially the tar used in urban roofs), and it costs extra money to get these materials produced in light colors. Yet many neighborhoods – especially in cities which tend to create vicious heat bubbles in the summer – are realizing the benefits to painting your roof white. The extra heat gathered by dark roofs in the summer puts a dramatic strain on energy consumption – and a needless one, if you consider that those roofs could just as easily be white. In fact, there is a nonprofit environmental group dedicated to painting the roofs in New York City white, one by one – claiming that if all of the roofs in the world were painted white, we would save a year’s worth of carbon emissions! This idea, while it might sound crazy, is actually backed by President Obama’s US Secretary of Energy, Steven Chu. While there might be aesthetic considerations to painting a sloped roof a really blinding white, says Chu, flat roofs that are not visible from below should all be painted white.
You also may want your roof to be a different color for aesthetic reasons. Perhaps you want a ‘warm’ composition for your exterior, but the roof shingles you inherited are a cool slate-gray. Or maybe you want your roof and your shutters to match, or you want to have accents in your siding that match your roofing color, and you just can’t make that work with the color you have up there. While it isn’t the most frequently used decoration strategy, painting your roof can be done, and it opens the doors to a whole new arena of creativity. And while the process does involve some degree of technical challenge, it is a good deal cheaper than ordering an all-new roof. It may also afford your roof some of the added protections that come with coatings, like water resistance, UV resistance, and abrasion resistance.
So, what is involved in painting your roof? First, it is probably a good idea to consult a professional, even if you intend to ultimately do the job yourself. You need to accurately identify the substrate you are working with, and the coatings it may have already been treated with, if you are going to pick the right tools and products. You also need to assess what condition your roof is in. Prior to coating, most roofs should be power-washed to ensure a clean surface, although a brand new roof without significant damage can probably benefit from a simple once-over with a leaf blower.
Many paint companies – Behr, Sherwin-Williams, and Benjamin Moore, as a few examples – offer paint products specifically intended for rooftops. These products have primers that are intended to adhere to the unique rooftop surfaces, as well as topcoats designed to weather the accentuated beating that rooftops get from the elements. A good roof topcoat has to be extra resistant to wind, water, abrasion (from debris), and especially the constantly beating sunlight.
If you are interested in coating your roof for environmental or energy-efficiency purposes, you may consider using a substance that isn’t technically a paint at all, but rather a highly insulate ceramic coating. The benefit of this substance is that its extra durability and reflectivity really shunt the extra heat away in the summer months, saving your air conditioner (and energy bill) from having to work overtime in the evening when the sun has faded away but a hot roof continues to radiate heat into the household.
So keep your mind open when you are figuring out your exterior design for the upcoming warm season. You may find an opportunity to exercise your creativity, save on your electricity bill – and help save the earth!