· by Michael Blair, Nashville's Roofers
Standing-seam metal costs roughly two to three times what an architectural asphalt roof does, and lasts roughly two to three times as long. On paper that is a wash. What decides it in Middle Tennessee is hail, attic heat, and how long you plan to stay.
How each handles our weather
Asphalt handles hail by absorbing it, which is why impact-rated shingles exist and why a hail event can total a roof that still sheds water. Metal dents rather than fractures, so a hailed metal roof usually keeps performing while looking worse.
Heat is the other factor. A light-colored metal roof reflects meaningfully more solar gain than dark asphalt, which shows up in attic temperature and, in a poorly insulated house, on the cooling bill.
The noise and lightning questions
Metal on solid decking with underlayment is not appreciably louder in rain than shingle. The drumming people remember is metal over open purlins on a barn, which is a different assembly entirely.
Metal does not attract lightning. It is not more likely to be struck, and because it is conductive and non-combustible it is arguably a safer surface if it is.
Where the cost actually goes
On standing seam, most of the premium is fabrication and labor rather than material. Complex roofs with many hips, valleys and penetrations cost disproportionately more in metal, because every one is a hand-formed detail.
A simple gable roof is where metal is most competitive. A cut-up roof with six dormers is where the gap is widest.
- Simple gable and hip roofs: metal is most competitive
- Complex cut-up roofs: the metal premium widens sharply
- Exposed-fastener panels are cheaper and shorter-lived than standing seam
- Impact-rated asphalt narrows the hail advantage for less money
Deciding by how long you will stay
Under about ten years, asphalt is almost always the rational choice. You will not reach the point where the longer life pays, and the resale premium for metal in most Nashville neighborhoods does not recover the difference.
Beyond fifteen or twenty years in the same house, metal starts to make sense — you avoid a second asphalt roof, and the maintenance in between is minimal.