Keeping Your House Cool
Metal roofing does an excellent job of keeping a house cool in a hot climate, potentially reducing the need for cooling by ten to fifteen percent. It does this by reflecting the sunlight from its surface instead of absorbing it.
This is what makes it different from asphalt because asphalt absorbs the suns heat as opposed to reflecting it. If shingles are black or dark in color, they will have a tendency to absorb more heat than if they were a lighter color.
Metal roofing is generally lighter in color, and this also helps to reflect more heat than the darker asphalt shingles. New, light-colored metal roofing will be highly effective at reflecting heat, and its heat-reflecting capabilities will be further improved through the use of proper ventilation and insulation.
There are also specially-designed sealants on the market that help to cool down the roofing material even further.
You Should Avoid Walking On Metal Roofs
Though you shouldnt have to walk on a roof that doesnt leak, there may be occasions when a plumber needs to snake out a vent pipe or a chimney sweep needs access to the chimney flue. You have to be very careful when walking on most metal roofsboth to avoid damaging or denting the roofing and to keep from slipping off.
You can walk on some metal roofs but not all of them. Whether or not they will dent from foot traffic depends on how the particular product is made and the type of construction supporting it. As you might imagine, metal can be very slippery when wet.
Some painted metal roof finishes can peel, chip, fade, scratch, or chalk, although nearly all premium products are guaranteed for at least 30 years. Walking on some types, particularly those with a granulated-stone surface, may cause surface wear. Installers must be careful not to scratch or dent the roofing during installation, and panels must be treated with care. Unlike conventional roofing, some metal shingle systems are installed from the top down, eliminating the need to walk on them.
Metal Roofs And Lighting
The misconception that metal roofs attract lightning is probably because metal itself is known as a good conductor of electricity, and people, therefore, assume that a metal roof must attract lightning. In reality, when lightning strikes, it is seeking a path to ground and almost always will strike whatever object is highest in the area that also has a direct path to ground. Your metal roof is not grounded, and thus lighting has no reason to strike it.
A metal roof in no way makes your home more vulnerable or susceptible to lightning strikes.
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What Are Cool Roofs
Cool roofs are made to reflect rays from the sun and absorb minimal heat. In comparison to traditional roofs, cool roofs have a high solar reflectance meaning they reflect more rays than traditional roofing. Moreover, their high thermal emittance helps them radiate heat into the air instead of your home.
The main advantage of cool roofing systems is that homeowners can expect to use less energy to cool their homes. In hot seasons, traditional roofs, regardless of color, can be as hot as 1500 F 1800 F, while a cool roof is between 50 and 600 F cooler under the same solar heat.
Misconception #: Heat Conductivity Is The Be All And End All
With all this talk of heat conductivity, you might be thinking its the most important consideration when choosing a roofing material.
The biggest contributor to a roofs heat gains is how much radiant heat that roof absorbs – in other words, how much heat it absorbs from the suns rays. Materials that are good at reflecting radiant heat are much better for keeping your home cool.
Thats the biggest advantage metal roofs have when it comes to heat gain – they reflect radiant energy much better than other roofing materials, like asphalt shingles. How well metal roofs reflect the suns rays will depend, in part, on what color they are.
For those of you who didnt know, metal roofs come in all sorts of different colors – the darker the color you choose, the more radiant energy the roof will absorb. For that reason, many people who are looking to keep their home cool opt for lighter colors.
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Are Shingle Or Metal Roofing Best For Warm Climates
Lets make it clear from the beginning: Metal roofs are a smarter idea than asphalt shingles in warm climates. But why? And why does it have to look so bad?
The reality today is that metal roofing isnt like the corrugated tin people put on chicken coops and storage barns decades ago. Todays metal roofing is available in many types, styles and colors. And since homes are being designed differently now, metal roofing often fits right in.
But surely all that metal makes a home hotter, doesnt it?
Actually, asphalt shingles absorb more heat, and that heat doesnt stop at the shingles. It absorbs into your homes structure, contributing to an indoor increase in temperature of up to 20 to 25 degrees, according to studies. Metal roofing, however, reflects away much of the suns hot rays, leading to an energy savings that can reach 50 percent. Thats easy to prove by measuring the temperature of an asphalt roof verses a high-quality metal roof. The metal roof can be as much as 100 degrees cooler in the same conditions, according to research.
Theres another factor: Shingles weaken with sun exposure, curling and cracking, decreasing their effectiveness against sun, rain wind and other environmental forces and leading to early replacement. Metal doesnt take in the heat as much, so it doesnt degrade because of it. It can last the entire life of a home with little maintenance, reflecting away heat all that time.
Do Metal Roofs Make Your House Hotter
When examining the advantages and disadvantages of upgrading your asphalt shingle roofing to a metal roof, it only makes sense to find the answer to this crucial question: do metal roofs make your house hotter?
This is a question homeowners frequently ask when deciding whether or not they want to install a metal roof and the answer can be the deciding factor in this decision process.
Lets bring some clarity to the subject.
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Metal Panels Can Go On Low
Most metal roofing materials can be installed on gently pitched roofs without leaking. Minimum roof pitch for metal shingles is typically 3-in-12this means the roof rises 3 inches for each horizontal foot. Some standing-seam roofing can be used on 2-in-12 roof pitch or, in some cases, even as low as 1-in-12.
In comparison, most asphalt or roof shingles cant be used on a roof with a lower pitch than 3-in-12 and materials such as tile require a slope that is 4-in-12 or steeper.
Can Black Roofs Melt The Snow
Since darker colored shingles absorb more heat than lighter colored shingles, it might help in melting minute amounts of snow. However, you should not rely on black roofs to melt snow as the difference they make is small.
Also, bear in mind that even a darker roof is cold and covered in snow during winter. As such, the roofs arent warm enough to melt snow, and with the snow covering, the black roofs transform into a lighter roof and reflect heat. As such, it doesnt matter if you have a black or lighter roof in winter.
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Advantages Greatly Outweigh The Drawbacks
Metal roofs continue to grow in popularity, and one of their “disadvantages” actually turns out to be an advantage when viewed from the big picture. Although initially much more expensive than an asphalt shingle roof , a metal roof lasts much, much longer, and in the final measure is usually the better investment.
Among the many advantages of a metal roof:
- The life expectancy is 50 to 75 years or even more, as opposed to the 15 to 25 years of life for an asphalt shingle roof.
- The surface reflects heat, lowering cooling costs in hot climates.
- They are less susceptible to leaking than shingles when installed correctly.
- They resist wind damage better than other roofing choices.
- Metal roofs are fireproof, making them good choices in areas where wildfire is a risk.
- Metal roofs are recyclable when they reach the end of their useful life.
Color Isn’t The Only Way To Reduce Heat Gain
In metal roofing, black and white are the most effective choices. Darker colors indeed absorb more heat than neutral and lighter hues. However, it is not as black-and-white as it sounds in metal roofing. Aside from color, various factors influence how much of the sun’s heat enters a building. Let’s go through some of them.
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Sun Exposure And Mass
The more direct sunlight a roof gets, the hotter it will become. As the sun goes down, your roof begins to cool until it reaches the same temperature as the air around it. However, heavier materials with more mass take longer to do so.
Lightweight materials lose heat the fastest, preventing that heat from transferring into your home. Luckily, metal roofing products are lighter than many other roofing material options.
Metal Roofing Doesnt Catch Fire
Because metal roof materials are noncombustible, they typically have a Class A fire rating . Flying sparks and embers will not set them on fire.
Just be aware that part of a roofs overall classification depends on materials beneath the surface that could ignite in intense heat, too. Most metal roofs applied over a combustible material such as wood shingles have a lower, Class C rating for this reason.
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Comparing Wood And Icf Construction
David Martin is intrigued with the idea of replacing his existing roof with a standing-seam metal roof. It should last longer than the alternatives, he says, and it would be compatible with photovoltaic panels should he decide to add them in the future.
So whats the issue?
David Martin is troubled by some of the advertising claims hes seen about metal roofing, specifically a statement from the Metal Roofing Alliance that a cool metal roof can save 25% in energy costs compared to a dark grey asphalt shingle.
Ive searched around the Internet and found a lot of the industrys advertising, David Martin writes in a post at GBAs Q& A forum, but Im a bit skeptical, especially after reading what Holladay says about the dubious claims made by manufacturers of bubble foils, radiant barriers, and open-cell spray foam.
It seems to David Martin that the biggest variable in energy efficiency is whether they roof is vented. I figure there would be a negligible benefit, if any, on a vented roof, he says. On an unvented roof, would the benefit be comparable to a radiant barrier on the underside of the rafters?
His questions about the energy benefits of a metal roof are the subject of this months Q& A Spotlight.
How Metal Roofs Affect House Temperature
Metal roofs have become increasingly popular among homeowners, especially now that theyre available in a much wider range of styles and finishes than in the past. They are no longer limited to the traditional barn roof style. They are more flexible, more attractive and more affordable. And with its energy efficient properties, it is not only good for the environment, but for your wallet too.
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Do Metal Roofs Keep Your Home Cooler
They can. But, generally, no.
Roofs are not made for keeping your home warm or cold. Theyre made to keep the weather out of your home. The first line of defense against the weather!
Air leaks and poor insulation could be why your home is hot during the summer, even when the AC is running.
Having a home with mature trees to provide shade will significantly help prevent the house from becoming so hot. This could provide issues with branches and debris falling on the roof, but that could have a simple remedy: cutting off branches that overhang the roof.
Generally, the roof itself isnt a significant factor in why your home becomes hot. Insulation and ventilation can become significant factors if you want to cool the house down when your air conditioning is running correctly.
A simple attic inspection from a professional HVAC company or roofing company should be able to tell you if your attic is adequately vented.
If your attic doesnt have proper ventilation, then heat could be trapped in your home, causing the heat to rise, leaving you to think that the roof is absorbing and retaining heat when its not.
Now, there are specific types of metal roofs that are specifically made to keep your home cool.
Cool roofs. Learn more about cool roofs from Energy.gov.
But the general metal roof would not produce a significant result in keeping your home cooler.
Which Metal Roof Colors Are The Coolest
Lighter colors tend to be more reflective and are typically the right choice when it comes to picking an energy efficient color for your metal roof. Colors such as pale blue, light green, white, beige and lighter bronze are especially good options if you live in a region that has lots of direct sunlight and a hotter year-round climate.
Additionally, the EPA has an entire list of Energy Star-certified roofing products and information available at
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How To Fix A Rusty Metal Roof
In this section, well outline the basic steps for metal roof rust repair. While its recommended that you treat rust before holes or cracks develop, urethane roofing cement is effective for making patches, which can withstand intense sunlight. The steps are as follows:
Things To Know About Metal Roofing
No longer a novelty, metal roofing has many advantages.
Lee has over two decades of hands-on experience remodeling, fixing, and improving homes, and has been providing home improvement advice for over 13 years.
Kelly Bacon is a licensed general contractor with over 40 years of experience in construction, home building and remodeling, and commercial building. He is a member of The Spruce Home Improvement Review Board.
The Spruce / Christopher Lee Foto
Metal roofing has entered the mainstream and is a viable option for nearly all homes, except those with very flat roof pitches. Not all metal roofs scream “metal.” There are now shingle-style metal roofing products that are almost indistinguishable from traditional asphalt shingle roofs. If you are wondering about the merits of metal roofing, here are 12 things to know.
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A Metal Roof Installs Fast
Metal roofing materials are sold as large standing-seam sheets or in multiple-shingle sections that are 12 to 36 inches wide. Standing seam sheets are typically 3 feet wide by 6, 8, 10, 12, 14, and 16 feet long. You can also get custom sizes.
An accomplished contractor can install these quickly. If your roof is stripped off and a storm is on the way, shortening the installation process by a day or two may offer a critical advantage. Obviously, there is also considerable cost savings if you can ease and shorten the duration of roof installation.
Green Or Living Roofs
A rooftop covered in moss and plants sounds like something straight out of The Hobbit, but oddly enough, it has a lot of practical value beyond its charm. Green roofs, which literally consist of plant life suspended over a waterproof membrane, have the benefit of both reducing heat loss and heat absorption, making them a suitable choice for both hot and cold climates. Additionally, they reduce what the scientific community refers to as the heat island effect: the temperature increase in urban areas resulting from the sun baking on asphalt and metal surfaces.
Likewise, they add necessary oxygen back into the environment, which makes them a vital asset for populated, congested areas. While certainly not the most popular roofing material, the idea is gaining ground among environmentally minded homeowners in hot-weather cities, so dont be surprised if one day you see neighbors out weeding their roofs. When it comes to protecting your home and keeping it cool, any material is fair game!
All images via Modernize unless otherwise stated
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