As an installer of metal roofing, I think I can contibute a bit of insight.4powells said:1. How do the costs of installing a metal roof compare to using traditional asphalt shingles?
2. How do the lifetimes of each product compare?
3. How much extra/less preparation is needed to install a metal roof (versus the shingles)
4. Having never spent any time inside a house with a metal roof, is there any aesthetic value inside the house? I.e. can you hear rain tap tap tapping on the roof?
First, "Metal" covers a lot of ground. The metal can be steel, galvalume, aluminum, copper, terne, and zinc. The shape can be in form of long panels (as in standing seam), wide panels (as in bermuda style), strongly profiled panels (as in spanish-look, etc), shingles (designed to look like shake, slate, 3-tab, etc.), and custom-formed.
Secondly, the finish on the metal varies. Steel, galvalume and aluminum are generally prepainted (again, a variety of paint systems are available), while copper, terne and zinc are usually allowed to oxidize naturally.
Thirdly, depending on which combination of features you like, the cost can be as little at $3.oo per sq.ft. installed up to $15.00 per sq.ft. Of course, at the low end, you have relatively low-quality finish, metal and installation method, whereas at the high end you got an architectural wonder.
Given these remarks, I can give you some general guidelines:
1- Metal roofs will almost always be more expensive than conventional shingle roofs. However, since the installer determines the quality of the final product, a good roofer can make even cheap materials perform well (but you will pay for his expertise), while a bad roofer will make a sieve of the best materials. So my usual response is for you to find the best roofer you can afford in your area, and let them suggest the materials thery are comfortable with.
2- roof lifetimes are like promises, a lot depends on which fingers and toes were crossed when the promises were made. With conventional roofing, we've seen 25-year shingle fail in as little as 10 years, and we've seen the same type last over 25. Some cheap metal will need repainting in as little as 10 years, and will be perforated in 25 (without maintenance), but others will last easily over 100 years without major work. Also, don't forget that a roof is like a chain - it fails at its weakest part. If a roof depends on caulking to be weather-proof, and the caulking has a life of (say) 5-years, then you have a five-year roof. Again, it is your roofer who for the most part determines whether the roof system lasts as long as it should.
3- in both cases, the roof must be properly prepared to accept the new roof covering. You can hide a lot of stuff under a new metal roof (especially if it is on strapping), but the compromises you make will catch up to you, sooner or later. If you are investing in a quality covering, spend the money to give it a good foundation. Each system will require its own type of preparation, so again, a knowledgeable and capable roofer is your best protection.
4- depends on the type of product and the installation method. Some metal roofs are no noisier than asphalt shingles, while others "contribute" their special ambiance.
So as you continue to develop your ideas for your dream home, think about what attributes are most important to you, what look you want to achieve, what durability you want to have, and then find the best roofer in your area to discuss your ideas with. Let them help you figure out which materials meet your needs the best.
I wish you good luck with your dream. In our own work, we often meet or exceed the homeowner's expectations, but we are specialized and only take on those clients where we feel we can deliver on their expectations. At the same time, we pay our craftsmen well, and the end result is expensive, unless the homeowners take an "investment" approach to this expenditure.