When it comes to roofing and roofing materials, you generally get what you pay for. Shingle manufacturers will advertise 10, 15, 20, 30, and even 50-year warranties. There is no such thing as a 50-year asphalt shingle, especially down here on the gulf coast. I’ll do my next blog on warranties to wade through those waters and explain what is and is not covered. It is typically assumed that metal roofs will last longer. This is mostly true.

Metal roofs are superior to asphalt shingles in several ways:

1) Metal is tough
2) Most metal manufacturers offer 25 and 40-year warranties (depending on the coating)
3) Metal deteriorates much more slowly (under most conditions)
4) When installed correctly, metal can handle higher winds
5) A wide variety of colors are available for metal roofs

Because the metal panels are more rigid than shingles, they can withstand higher winds.
With multiple screws holding each panel in place and the panels overlapping each other, a very
strong roof is achieved if installed properly.

Metal has its downsides, too:

1) It is considerably louder when it rains (I like the sound of rain on a metal roof)
2) The screws, or washers, have a reputation for dry-rotting, which creates leaks
3) Those vivid colors sometimes fade (see pink from red or light green from dark green)
4) Metal is susceptible to being installed poorly, which isn’t immediately apparent
5) Corrosion is a concern, especially at the coast or under certain trees

The screws, and soft washers on them, can deteriorate over time. This is less common than
some ‘shingle only’ roofers would like you to believe. I have heard rumors of some insurance companies requiring screws to be changed after a certain number of years, but I have never heard this firsthand from an insurer. The reality is that the screw/washer is the likely culprit if a leak does occur later down the road with metal.

With installation, just like shingles, make sure you use a licensed roofer. There are 2 common methods of installation of metal panels. First, the right way is to remove all old roofing materials from the wooden decking. This allows for inspection, renailing, and, where necessary, replacement of rotten or water-destroyed wood. After the decking is secured, a top quality high temp underlayment should be installed, and the metal panels should be directly on top of the
underlayment. The other method, which we will not do, allows the old shingles to be left on the roof. This is much cheaper, cleaner, and easier. Narrow strips of wood are screwed to the roof directly through the old roofing materials, and then the metal is screwed onto these strips of wood (usually called purlins). Building code allows this, but just as building code allows a shingle-over method of roofing, it doesn’t mean it is the best way. The biggest problem with this method is
the securement of the roof. Did the purlin secure to a truss or just the plywood? Is there rotten or damaged plywood under those shingles? Did the screws holding the purlins down hit a gap between sheets of plywood? Often, these things aren’t known until a storm comes.

Finally, on to the idea that metal lasts much longer than shingles. This is partially true. Under most circumstances, metal will indeed last longer than asphalt shingles. Atmospheric conditions, just as with shingles, make the most difference.

I live in a neighborhood with a lot of low-flying jet aircraft. The Blue Angels practice right over my house and have been known to smoke out my street. It’s pretty great. But the unburnt fuel can be smelled in the air sometimes. This is definitely tougher on metal and the screws that hold it. Consider, too, the effect that living near the coast has on cars, boat trailers, grills, etc. The same thing happens to a metal roof. The coatings on metal roofs help but keep in mind that everywhere a screw is installed, a hole is created in that protective coating. Everywhere the metal is cut, the protective coating is cut. If the metal is scratched or has a tree rubbing against it, the coating is compromised.

Along the coast, you do see more metal roofs as a percentage than away from the coast. This is due to the higher strength and wind ratings of metal. Metal is superior in most circumstances to asphalt shingles. I want it to be known that metal does indeed have its drawbacks.

Price is another factor to consider; expect to pay 50-70% more for metal roofing than shingles. Is it worth the extra money? That is up to the buyer. What is right for one home may not be right for another. With shingles, if you don’t like the color, you can put a different color on it in 20 years or so when you need a new roof. With metal, you have a lot of life left at 20 years, even if the color has faded. With a metal roof, it is possible to get 40+ years of trouble-free service. Will you still live in that house in 40 years?

Even with a metal roof, there will come a time when it is time for a re-roof. With the higher cost of a metal roof, this is definitely harder to stomach. Consider, too, that any moisture that has occurred under a metal roof for all of those years will definitely have caused more wood to need replacing, which will add to the cost.

So in closing, metal is a longer-term roof. But whether the metal is right for your project is up to you, your budget, and your needs. A licensed roofer, who does more than one thing, will be happy to help you make that decision based on what will best serve you.