roof, and that you’ve got skylights, and you’d also like to be able to walk up top, I’d recommend you forget metal. There are three reasons why:

1. Painted metal roof finishes don’t last as long as asphalt shingles.
2. It’s easier to waterproof around skylights using shingles.
3. Metal makes a roof difficult to walk on safely.

Despite all the impressive sounding warranties for metal roofs, I have yet to see one that doesn’t look bad after 20 to 30 years. Finish failure is the reason why. No matter how good the paint is, it’s still quite a lot to expect it to keep looking sharp after three decades. A metal roof might keep water out for a long time, but what does it matter if the surface is dull and faded? By comparison it’s easy to find high-end asphalt shingles with 50-year and even lifetime warranties.

I also know from experience that it’s much easier to create a waterproof connection between a shingled roof and skylights than it is with metal. Asphalt is also the best surface for walking on. Metal is slippery and the textured versions can be damaged under foot.

Since your location has trees, be sure to install exposed zinc strips just below the peak if you do go with asphalt. Rainwater dissolves tiny amounts of this harmless metal, preventing moss and lichen from growing. If your roof is longer than 20 feet from the peak, you’ll need to install a second zinc strip half way down the roof, extending about an inch beyond the bottom edge of one row of shingles.