When my husband and I first moved to the country, I was amazed at the number of homes in our neck of the Georgia woods that had metal roofs . . . and at the number of those tin-topped abodes that displayed "For Sale" signs out front. So the next time I spoke with a local realtor friend, I asked him if he found it difficult to market metal-roofed houses. At the question, his face cracked with a knowing smile.
"Anything with a tin roof is going to sell for less . . . if you can find a buyer for it at all," he told me. "Even your typical back-to-the-lander doesn't want to take one of those buildings on. And most of the people to whom I do manage to sell metal-topped homes tell me they plan to replace the roof as soon as they get the money together."
"Well," I said to myself, "if my friend is right, and if my area is typical, it seems that buying a home topped with tin might be one way to save a good bit of money . . . and such a move could make it possible for a would-be ruralite to settle in the country that much sooner." In short, my curiosity was whetted, and — since we had some city friends looking for a bargain-priced house near us — I decided to learn all I could about metal roofing pros and cons. I wanted, above all, to discover why they suffer such a poor reputation . . . and if they deserve it. It's taken some time, but what I've learned has really opened my eyes to the hidden benefits of tin-tops . . . and I'd like to share some of that knowledge with you here.
First of all, most "tin" roofs aren't made of tin. You see, there are several metals used for roofing. Below, I've listed those you're most likely to encounter, along with some of the strong and weak points of each.
Galvanized Steel. This is a wonderfully inexpensive roofing material that will last 60 years or more . . . if properly cared for. It's made of alloyed steel, with a protective coating of zinc. Galvanized steel is also highly rust-resistant.
Aluminum. The use of aluminum as a roofing metal is becoming increasingly popular, since it resists corrosion and requires little maintenance. Aluminum also tends to reflect heat better than steel, thus keeping a house cooler during the summer. Aluminum roofs will last about 35 years.
Copper. You won't see copper being used for roofing much these days, even though it's by far the longest-lasting of all roofing materials (many penny-metal lids have lasted hundreds of years and appear to have hundreds more left in them). Unfortunately, this material is not only quite expensive, but also difficult to obtain.
Metal Roofing Pros And Cons
Is a metal roof — any metal roof — worth considering if you're shopping for a home . . . or if, perhaps, you're in need of a new top for the old shanty? It's hard to say — flat out — either yes or no. But, in hopes of helping you make the choice that's best for you, I've compiled a list of tin-roof characteristics . . . both good and bad. First, let's take a look at the bad news:
To provide protection against lightning, you'll need to spend a few bucks to rig a proper grounding arrangement. What's more, in seacoast areas where the air is laden with corrosive salt, a metal roof's life span may be fairly short. Similarly, polluted air in industrial areas makes tin topping less enduring than non-metallic roofing. And finally, metal roofs are noisy in the rain. (But what might be an "infernal racket" to one person could be a "comforting tap, tap, tap" to another.)
And now for the good news: Metal roofs are durable (Monticello — Thomas Jefferson's Virginia home — still wears its original "tin" roof . . . and it's in fine shape to this day). And in areas that receive heavy snowfalls, such lids — with their slick, low-friction surfaces — shed the white stuff so quickly that it rarely has a chance to build up to weighty depths.
Most roofing metals are also tough enough to resist damage from hail and falling tree limbs. Moreover, since metal doesn't burn, it's especially appropriate for houses with stovepipes and chimneys . . . a comforting thought when you live far from the nearest fire station.
And to add a final trio of tin-roof routings, the large metal "shingles" are easy to install, go on quickly, and — when compared with many other roofing materials over the long haul — are generally inexpensive.
Evaluating an Existing Metal Roof
OK, let's say you decide that buying a house with a metal roof just might provide you with a shortcut to the country. You'll still want your new home to be topped with a healthy slab of sheeting, and you'll need to know the signs that provide clues to the condition of your prospective home's "hat".
Of course, the logical starting place is to determine the type of metal the roof is made of, and you can usually do that with just an exterior appraisal. Steel roofs — when rusty — have a reddish color. Copper oxidizes to a light green. Aluminum changes hues according to the degree of oxidation, but progressing from white to gray to black.
When you've determined the type of material used for the roof, take a look from a distance to see if there's bulging or buckling anywhere. If there is, chances are that the structure has been poorly constructed or that leaks have rotted some of the bracing or framing. If this is the case, I'd advise extreme caution . . . you could be talking about extensive — and expensive — repairs.
Try to find a way to climb up onto the roof for a bird's-eye view. Since metal roofing is laid on in large sheets, pay special attention to the seams. Also, look closely at the ridge and around the chimney (where it disappears into the roof). These are the places where you're most likely to spot signs of leaking. Are there a lot of popped-up nails or an abundance of roofing-tar patches? Again, these may indicate that the roof leaks, or has leaked in the past.
Check to see if flashings (metal "gaskets" used to direct water away from critical areas) have been installed where they should be: around chimneys and stovepipes, along eaves and hips, and in the valleys. If there's no flashing, you'll want to correct that problem right away should you buy the house.
Now go inside the building, scamper up into the attic, and — with a flashlight — peer into the dark corners. Look everywhere for signs of water damage, especially around the top of the chimney or stovepipe. And while you're up there with the dust and spiders, try to spy out the top plates of the wall studs to determine how sound they are. If they're badly rotted, it could indicate a pervasive condition in the hidden stud walls. (If a house has this problem, I'd forget about trying to make it your home.)
Repairing Metal Roofs
There's one cardinal rule to remember when doing tin-top patching: Some metals, if placed in contact with certain others, can generate an electrolytic reaction that will result in rapid corrosion. To avoid that nasty possibility, be sure to patch copper roofs with copper, tin with tin, and so on.
If portions of the roof are badly damaged, you can remove the injured panels and replace them with new material, but be careful not to harm the adjoining healthy sheets when you're pulling the nails. Be sure to use neoprene-gasketed nails for the new application: They're specifically designed to prevent leaks. Drive your nails in at the high points of the corrugation . . . not in the valleys. (Or, insert neoprene-gasketed "drill screws" with a power drill to provide a watertight seal.)
If there appears to be any leakage through the existing nail holes, squeeze a dab of silicone caulking around and under the nailheads before you whap them back down. (Leaking seams may also be caulked.)
Soldering is an effective method of mending splits and holes in a metal roof (except in aluminum). Solder tin and galvanized steel with rosin flux, and copper with acid flux. Be sure to heat the metal sufficiently to avoid getting a weakling cold joint, but use an iron to prevent temperatures from going too high.
If your roof doesn't have flashing in the appropriate places, you'll need to add it. For aluminum roofs, use .024 inch aluminum flashing material. For galvanized steel, use a matching metal, but in a thickness one gauge heavier than the roofing itself. Place flashings in the valleys, at the eaves and hips, and — of special importance — around chimneys. (Check with your local building-supply house for ready-made valley sheets and other flashing materials . . . or — if you have the necessary tools and skills — you can cut and bend them yourself.)
Prevent Lightning Damage to Metal Roofs
Too many metal-topped houses aren't properly grounded to prevent damage from lightning. Grounding will provide a path for the electrical current of a lightning strike so that it will bypass the house and enter the earth, where it can do no harm. If your home is not properly grounded, the lightning can easily pass through the structure, perhaps blowing out the electrical system or causing fire and personal injury.
Painting Metal Roofs
Painting can spruce up the appearance of an older metal roof and add years to its useful life. Aluminum roofs don't need painting, but galvanized steel can benefit dramatically from a new finish. When you buy roof paint, don't scrimp on quality . . . unless you want to do the job again soon. One coat of good paint is usually adequate, but two is always better. The paint best suited for use on galvanized steel is a zinc-dust type . . . it'll adhere well and won't peel. You can also use the less expensive cement-based and latex coatings, but be certain that those you choose are formulated specifically for galvanized steel. Avoid aluminum-based finishes.
You can paint with a brush, a roller, or a sprayer, the first being the most materials-efficient method and the last being the fastest. But before painting, do remove any rust with a wire brush (or steel wool, if it's only a small area), and give the roof a good sweeping. Then scrub it down with clean water and an old mop. Make sure the housetop is bone-dry before you start slopping on the first coat, and pick a warm, sunny day to do the work.
Metal Roofing Basics
My intention hasn't been so much to sell you on the virtues and advantages of "tin" roofs as it has been to supply you with enough basic information to balance against the bad press that metal roofing has suffered so often in the past. Of course, my investigations have made some lasting impressions on me . . . and when we build a small guest cabin on our property soon, it'll most certainly be dressed out in a shiny new galvanized cap!
Originally Published: March/April 1984
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My experience here in North and South Carolina is not that metal (aluminum) is cheaper than shingles. It wasn't for me. The benefits are longer life, heat reduction, and less accumulation of leaves.
Things have changed in the 30 years since this article was written! Our standing seam roof is ten years old and looks like new. Our previous shingle roof looked like hell after 20 years and I got tired of patching it. I reroofed my garage too, and the most time consuming part was ripping off the old shingles. I got a tax deduction for having a shiny roof that reflects sunlight (it looks brown). It's quiet because I have lots of insulation under a plywood deck. There's no screws that show because it's a crimped-on standing seam. The snow slides off and no raking or shoveling is needed. It doesn't "trap heat" worse than shingles. About cellphone reception: I'm an RF engineer and you won't get GPS because those satellites are overhead. But cellphone towers are on the horizon and work through the walls or windows so if they are not metal you have a chance. If someone (not me) needs to take the roof off in 100 years, it's recycleable. The only downside is that the snow slides off into a thick glacier that's right in front of my front door. I'm thinking of putting snow catchers up there. Bottom line, no more shingles again for me! It was a lot more expensive, but worth it.
I have a standing seam metal roof, I live in Vermont. If you have snow that measure in FEET not in "oh look the grass is white" and melts in by noon, a metal is literally a life saver. The snow falls, a day or 2 later the sun does eventually come out and the snow sheds off the house and barns and I do not have to climb up there and shovel it off. Metal roof, will never live in a house without one again.
I have had metal and shingle. Other than a slight reduction in SOME brands of cellphone capability, there is no downside to metal roofs that I see. If noise is a problem it is not because of a metal roof. It is because of a lack of insulation. I am starting to think that shingle roofs are like carpet as opposed to wood floors. A scam being put on us by roofing and carpeting companies.
YankeeDragon just brought up an extremely important concern. My cellphone will not work inside my mobile home. I would like to see an article on cell phone reception/transmission and internet reception both in a home with a metal roof and or a mobile home and living many miles away from a city.
There is a sizable portion of us that live in "mobile homes" whether they are "trailers" or "modular" or "prefab" homes and are single wide, double wide and some triple wide, that are advancing in age and an article on the benefit verses the comparative cost of putting a new roof or a "roof over" would be much appreciated. Also, you briefly touched on grounding for a metal roof which could be elaborated upon in addition to the concept of gutters and the system of saving the rain water along with understanding just what will "leach" into the water from a metal roof made of galvanized or steel. So, Mother Earth, how about an update since this is from 1984 along with adding answers to the additional topics.
You really need to rethink sending out an article from 1984 to tout the pros and cons of metal roofs. I live in Maine and I have a metal roof. When you have heavy snow, you’ll appreciate the fact that the snow slides off and you don’t have to use a roof rake or crawl on the roof to shovel snow. If you hear rain hitting the roof, you have another problem...called a lack of insulation. Even in heavy rainfalls, I don’t hear anything. Finally, metal roofs come in a variety of colors and different textures to fit anyone’s tastes. I just bought a house with a metal roof and the only downfall I’ve encountered, that wasn’t around in 1984, was that cellphone signals are dampened by metal and you may have to invest in a signal booster (not cheap!) to use your cellphone indoors.
AI live in NW Ontario and would never, ever, put another metal roof on my home! The wide variation in temperature moves the roofing (you can hear it). That either cuts slots in the metal or loosens the crews. I had it removed and replaced with shingles. The wood under the metal roof had rotted in many places so had to have that replaced. A metal roof is ok for a shed or unheated garage but even there they always start leaking after a while.
Thank your so much for this article! I have learned a tremendous amount here, which will help me with a decision on purchasing my first house!
This article is from 1984... what?!!!!!!
My ex husband and best friend has a big problem with raccoons breaking into the roof and basically moving in. On many occasions he has had them humanely removed and than have the roof repaired only to have them chew their way back into the attic, one time through the garage. Is having a metal roof a good option in this case? Please send me any suggestions you have for this very expensive problem. It is also very unsafe.
I read your article on the metal roofs and thought it was pretty good even though I had to smile to myself some of the times. I'm 51 and have lived here in the South all my life. I grew up in house that were topped with galvanized "tin" roofs. The noise of rain on these tin roofs has always been a form of "white-noise" that lulls you to sleep. It might bother some folks at first but once you get used to it, it won't bother you a bit. And as long as I can remember, I don't remember a house getting struck by lightning because of a metal roof. Well, no more than houses topped with shingles. It's become common place these days for folks that own houses with conventional shingles to replace those with metal once they wear out. In fact, when my roof needs replacing I will be putting the newest painted metal roof on it. From a replacement standpoint you can't go wrong. These new painted metals have a 50 year warranty on them. I guess what I'm trying to say that for folks that know, metal roofs ain't a bad thing. Good article though, I look forward to more. Thanks
Out here they are called "iron" roofs (from galvanised iron) and are common in the majority of houses up to 15 years ago. The recent financial boom (pre 2008), brought in many more tile roofs. I've lived with an iron roof most of my life - from a house with 100 year-old Scottish made iron (still water-tight) and all sorts. The construction for iron is much lighter than for tile - a massive saving in timber and labour costs. The iron (now either galvanised steel or a steel substrate coated in an aluminium/zinc coat - then with a colour electro-coated over the top), is traditionally in the wavy pattern (though there are many others) and is available in almost any length, thus with far fewer points of entry for water. Secondly - in this earthquake zone, the iron is well screwed down, in effect forming a full "box-construction" and reinforcing the timber structure. In the Christchurch earthquake, tile roofs "exploded" with the tremor, iron roofs flexed, but remained in place. Chimneys fell THROUGH tile roofs but slid off iron - totally wrecking the iron of course, but not crashing though on the occupants. I chose galvanised coating - in the heavy grade (2 grades available), as I draw my drinking water from the roof and also as it was cheaper than the Colorbond. In this area this plain iron lasts between fifty and seventy years. It is important with galv' iron to paint the points where the sheets overlap to forestall electrolysis - simply over lay the sheets sequentially, upside down so that the area that will overlap is exposed and coat with a good non-toxic paint. The overlap I allowed was for 1.5 ridges. When fitting I also double screwed the bottom edge on every second rise rather than the alternating 3rd and then 4th rise - as further up the roof. So, cheaper construction, cheaper to roof (and you can DIY) and safer. What is it about tile you like?
I have tar roof tiles now and due to being in northwest the moss grows tremendously. Cost involved in hiring someone to clean it. Was thinking of installing metal roof over it but not touching the current roof. As in putting in 3" supports to hold up a metal roof to let air flow thru between current roof and new one. Would that work, I wonder?
You didn't mention condensation. On my metal (ProPanel) roof condensation forms on the underside of the valleys and moves to the low edge where it pools (very low pitch). The house is in the desert so there is little humidity and the damage is slow and slight. I think the roof should be grooved, flashed and caulked (on the high side) at the edge. That is, a groove cut so that the edge of the flashing (bent 90 degrees) is not sticking up for water to go under.
you don't see many copper roofs around anymore...
I have just recently had a metal roof installed on my home lets clear one thing up from the get go my metal roof is much quieter than my shingle roof ever was I now no longer have the sandy material that was coming off my shingle roof clogging my gutters the type of roof I had installed cut the seams in the roofing material surface by 75% less seam less places for moisture to get in my roof is of a aluminum type material warrantied forever or put it this way I will be long gone before I ever need to worry about my roof again lastly in the area where we live a metal roof is a highly desirable upgrade to a home in fact it helps to bring the value of your home up a definite bonus for someone shopping for a home