Roofs in New England are angled to shed precipitation (snow builds up and can fall through a flat roof). It seems that most roofs are shingles of some kind, sometimes pieces of slate, and rarely sheets of metal.
Shingles have to be replaced after a period of time because they are organic and can rot; also, the roofers might lay a few incorrectly, resulting in an imperfect seal and letting water into the roof and accelerating decomposition.
Slate is brittle - it can be chipped at by sleet and such, and worn away slowly by rain. More importantly, if water gets in between slate pieces and the roof in the winter, ice will expand and crack the stone right off.
Metal roofs, painted to avoid blinding people, seem to be the best choice. It’s easy to find steel that rusts little (it’s painted too), and the roof will shed rain and snow easily, being much flatter than another kind of roof. Why are metal roofs not more common? Is it the noise during rain? Is it the weight (doubtful)? Is it the expense?
I don’t know why they’re not more popular, but at the last few Home Shows I attended, there were several vendors with samples of metal roofing materials. Some were formed and coated to look like shingles, but they were designed to be installed in fairly large panels. We were impressed enough that we hope to use them on our retirement home. I believe they’re warranteed for 50 years.
I expect people like the look of shingles - certainly they’re essential if you want a specific look for your home. I expect asphalt shingles are pretty cheap, and being available in many colors is an advantage there. I would also imagine lots of people aren’t aware of their options - they just stick with what they know.
Regarding shrinking/expansion under cyclic temperature variations, a large number of small pieces will perform better than a small number of large pieces.
Another idea might be that driving nails to attach metal to the roof can introduce leakage. There’s a hole to start with, and certain metal-pairs react and could make the hole grow with time if the wrong materials are used (nobody’s perfect). The shrink/expand over time could aggravate that.
Also, as a nit, I’m in NE too and most roofs are asphalt shingles which do wear out but don’t rot.
I priced the “metal shingles” mentioned by FairyChatMom and found the installed cost to be three times that of conventional shingles. I had been interested in using them for a house now under construction. They looked really nice though.
A material used on a roof is chosen not only for durability, but it’s also part of the “style” of the house. You would not expect to see terracotta tiles on a colonial style house. OK, that’s a little extreme, but you get the idea.
A metal roof looks good on some styles, but I think shingles look good on most styles built in the NE and midwest. I’d venture that they are also a good value for the money.
Historically, cedar shingles were used because they are easy to fabricate using a few extremely simple and inexpensive tools. Cedar is a “sweet” wood that splits readily and cleaves into thin regular planes. The low density of cedar shakes also makes for a lighter roof that does not require as much internal support. They eliminate the need for costly, harder to find, larger and more cumbersome roof beams.
Shingles are small and easy to install or repair. They can also be replaced individually. Larger roofing panels are heavy, difficult to hoist into position, awkward to fasten plus subject to greater dimensional shift and stress during thermal cycling. Larger panels also represent an increased danger of accident during installation by dint of their higher mass. This can cause a person who is handling them to commit to a fall more easily than a small shingle weighing only a few ounces. The roof is also a windy place and larger panels have sail-like qualities that are very undesirable in terms of safe handling. Shingles may be installed by a single individual whereas larger panels necessitate a hoist and crew.
The specific overlapping design of shingling readily sheds water yet allows the roof to “breathe.” This combats dry rot and other moisture related damage plus it permits the house to lose heat during the summer. The high tannin concentration in cedar also resists pest related damage. Installation hardware for shingling is a rather simple affair. A hammer and some nails. For most of recorded history this has made shingling one of the most efficient and popular methods of roofing a building.
Nowadays, asphalt shingles are the primary choice of houses. I am old enough to remember the Woodway Square fire in Houston (1978), where about a 12 square block apartment complex burned due to wood shingles. Wood shingles get extremely flammable over time, plus asphalt is likely cheaper.
I just replaced my deteriorating shake roof with stone coated steel - I decided there were a lot of advantages. About the same price as shake - a bunch more than composite shingle. The composite is probably the better “value” since the expected lifetime of metal is comparable to a good composite roof.
Steel roofing comes in a lot of styles. I wanted something that looks like tile (stucco house). I can’t put real tile on this place - the weight would collapse it. There are “lightweight tile” products, but they have serious problems with walkability, and are still heavier than composite or shake.
One of the chief advantages of metal tile is that it is VERY light - when they were putting the stuff on, I picked up a few of them and looked at them. It’s sort of like covering your house with pie plates. In addition to putting less structural load on the house (a help in earthquake country), the steel tile supposedly adds some reinforcement. Metal is also very fire and wind proof. It isn’t any noisier than any other roof.
The main disadvantage besides cost is probably walkability - you’re supposed to be careful walking on them to put your feet where the battens are. Not as fragile as lightweight tile, but not as able to be walked on carelessly as shingles.
Speaking as a guy who did nothing but roofing work for three summers, I can tell you that aphalt shingles have many advantages. Cheap, looks nice, and installation is a so much easier, Imagine trying to get around a vent pipe with a metal roof, especially if the pipe is in the middle of the gigantic 10’x5’ sheet of metal. You have to measure it exactly to get the right position, and then cutting out a circle in the middle of the metal is no easy job. SHingles are so small that even though three or four may touch the vent, each only requires a small semi-circle cout out of it, easily done with a utility knife. Also, putting on an asphalt roof can easily be done by one person. And with two or three, it can go very fast. With a good set of roofers and good equipment (air hammer) the time between when one shingle is odne and another is done can be a few seconds.
Lead roofs are virtually indestructible and last for at least 100 years. But they are very heavy and cannot be used unless planned for during construction (or so I have read). When I was in Japan, I noticed nearly all roofs were lead colored tiles and I assume that they were matching the appearance of actual lead. Copper roofs (which turn green after a few years, first oxidizing to brown, then combining with carbon dioxide to make copper carbonate) are excellent and can last hundreds of years but are extremely expensive. I don’t expect to occupy my house for hundreds of years, so I chose cheap asphalt tiles and will let the next owner replace it.
If lead roofing were ubiquitous, the runoff precipitation might pose definite problems for the environment.
[politically correct hat cheerfully taken off]
Great point, bouv, about how shingles can be modified in situ for various roof penetrations. A huge plus over trying to figure out just exactly where to position a vent hole when installing big sheets of copper that must have all modifications done on the ground.
Sue, one reason for all of the metal roofing up in Lake Tahoe is that they can be readily modified for electrical heating. This permits controlled shedding of the snow burden, thereby reducing the structural load upon the house. It also helps to avoid formation of massive icicles that actually have been know to kill people.
There have been great advances in metal roofing in recent years like baked on powder epoxy paint and new constructions where the nails are concealed and so do not allow rain to reach them. Also insulation has improved. Early metal roofs were hot in the summer, cold in the winter, and loud in a rainstorm. They also needed to be painted. Paint is still a small problem, scratch it (tree limb falling on the roof) and you can have a leak in a few years. However new epoxy paints are very tough. Aluminium was durable but you have to be careful of steel nails which will eat through the aluminium. Has to do with electricity, just as tin will be eroded before the steel starts corroding.
But most of the roofs on buildings in Vilnius that are over 75 years old are metal. The rest are clay tiles being replaced by metal look alikes in some cases. Soviets used either flat commercial roofing (concrete slabs, I beleive, sealed with roofing - they leak between the slabs.) or fiberglass.
I think this may be the main reason anything more expensive than asphalt shingles hasn’t become more popular. I have no idea what the average amount of time people stay in the same house might be. I doubt the cost of the more expensive roofs can be completely recovered at resale. So, if I’m going to stay in my house another 10 years, as long as the roof is going to last another 12 (so it doesn’t look like it needs replaced right away when I try to sell), I’m happy and I’m going to let the next owner worry about when the roof needs replaced next.