Step one: understanding what you need
I walk the roof and the attic and work out why the old roof failed. Age, heat, a bad original install, tree damage, a previous overlay that trapped moisture. The reason shapes the replacement, because a roof that failed from poor ventilation will fail again if the new one has the same attic.
I also ask what you want from the house: staying twenty years, selling in two, adding solar next year. Those change the material advice.
Step two: explaining the options
Composition shingle in standard or high-wind grades, concrete or clay tile, a tile re-lay reusing your existing tiles over new underlayment, metal panels, or a cool-roof shingle that meets the state energy code with a lighter color. Each has a cost band, a life expectancy and a look, and I go through all three honestly.
Overlay versus tear-off is part of this conversation, and I have a whole blog post on when an overlay is acceptable.
Step three: preparing you for the decisions
Materials, timeline, product warranty and workmanship guarantee all get written down before you sign. You will know which days the crew is there, where the dumpster goes, what happens to the satellite dish and the solar panels, and what the roof looks like at the end of each day.
The permit is pulled in your name with the city or county, and the inspection is scheduled by me.
What the crew does
Tear-off to the deck, replacement of any soft or delaminated sheathing, new drip edge, ice-and-water membrane in valleys and around penetrations, synthetic underlayment, then the new roof covering with new flashings at every chimney, wall and pipe. Ridge ventilation is added where the attic needs it.
Every evening the site is tidied and a magnet run over the yard and driveway.
Tile re-lays specifically
Half the tile roofs in the valley have good tiles over dead felt. Lifting, stacking, re-felting and resetting saves the cost of new tile and keeps the look the neighborhood expects. Broken tiles are swapped for matched pieces and the ridge is rebuilt on a mechanical system that the wind cannot loosen.
It is slower than a shingle job and needs care, but it is the right answer for a lot of houses here.