Twenty miles from salt to none
This county is narrow and it crosses two different worlds. A house in El Cid and a house in Wellington can be identical on paper and be doing entirely different things twenty years later, and the reason is in the air.
- 1 The ridge. The highest, hottest course, and where a shared roof usually begins and ends.
- 2 The field. Tile or shingle above, and the underlayment that actually keeps water out below.
- 3 The valley. One channel carrying what two slopes shed, and where debris settles between rains.
- 4 Wall flashing. Where an addition or an enclosure meets the house, and where neither trade owns the seam.
- 5 Penetrations. Collars, curbs and skylights: holes cut on purpose, then sealed. They open first.
- 6 Eaves and metal. Drip edge and fasteners. Near the water they end the roof; twelve miles west they do not.
What salt actually reaches
Not the covering, first. Salt-carrying air works on metal, and a roof is held together by metal: fastener heads, drip edge, valley metal, and the flashing at every wall, curb and penetration. Those parts are thinner than anything else up there and they carry the load that keeps water moving off the roof.
The failure then runs upward. A fastener loses its head or its seal, the piece it held moves slightly, the movement opens the seal beside it, and water reaches the layer underneath. None of that is visible from the driveway.
The gradient is real and it is steep
On the Intracoastal and the barrier communities, the exposure is daily and year-round. Two or three miles inland it is meaningfully lower. By the time you reach Royal Palm Beach and Wellington it stops being the governing factor altogether, and what ages the roof is sun and the summer rain.
That flips which part of the roof is the limiting one. On the coast, the hardware often ends the roof while the covering still looks serviceable. Inland, the covering and the underlayment run their normal course and the metal keeps up.
What to do with it
Specify the hardware to the address, not to the county. Coated or stainless fasteners and rebuilt rather than sealed flashing cost more on the day and are the whole difference within a few miles of open water. Further west that same money is better spent on the underlayment.
A contractor who quotes the same specification from Palm Beach to Wellington is quoting from a price list rather than from the house.