http://www.roofcalc.org/diy-solar-metal-roof-part-1-planning-budgeting/
► Always replace your roof before installing Solar Panels

Roof (asphalt) shingles are MADE TO FAIL after 10-20 years. It’s a business model, to ensure that homeowners keep buying new shingles!

Shingles fail even faster when they get too hot (such as under solar panels). Having multiple penetrations for solar raking, creates additional AND significant chance of leaks.

This solar PV system was originally installed in Fall of 2015, and in December 2015, it came off, becasue the roof failed, and had to be replaced!

Homeowner did the right thing and got a Metal Roof, which is life time product.

When solar was replaced, racking was attached to rails with S-5 Clamps, to make sure there are no penetrations!

This is the only way to do solar the right way. If you don’t want to waste youyr money, always replace the roof before doing solar. I also recommend doing a metal roof. You can estimate cost of Solar PV + Metal Roof here: http://www.roofcalc.org/solar-roofing-calculator/