How to Weatherproof Windows and Doors Against Coastal Storms

Every wall assembly you build, every coat of paint you apply, all of it comes down to a simple truth: water finds the openings. On a coastal home, wind-driven rain does not fall, it flies sideways and pushes against every window and door like a pressure washer. That is why the openings, not the siding, are where most storm damage begins. The good news is that a few proven details can turn the weakest points of your house into some of its toughest.

Begin with the flashing. Above every window and door head, there should be a metal drip cap or head flashing that laps over the top flange of the unit and sheds water out past the siding. Too many installations rely on caulk alone, and caulk fails within a few seasons in salt air and sun. Sill pans matter just as much. A sloped sill pan under the window directs any water that sneaks past the sash back to the exterior instead of into the wall cavity. If you are replacing windows, insist on both. If you are not, at least inspect and renew the sealant joints each fall.

Sealing Without Trapping Moisture

Here is the counterintuitive part: you can seal a window too well. Coastal walls need to dry, and if you caulk every seam on the interior and exterior, moisture from inside the house gets trapped and rots the framing. The right approach is to seal the exterior against rain while letting the wall breathe. Use a vapor-permeable house wrap, tape the seams properly, and leave small drainage gaps at the bottom of the siding where water can escape.

For the windows themselves, look at impact-rated glass if you live in a hurricane zone. Impact glazing resists flying debris and, just as importantly, keeps the building envelope intact so wind pressure does not lift the roof. Storm shutters, whether roll-down, accordion, or simple plywood panels stored in the garage, remain the affordable backup. Whatever system you choose, practice deploying it before a storm is on the radar, not during one.

Doors, Thresholds, and the Details People Forget

Exterior doors take a beating. The threshold is the first line of defense, so choose an adjustable sill with a good gasket and keep it clean of sand and grit that can crush the seal. Add a storm door on the windward side if your exposure is severe. Check the sweep at the bottom and the weatherstripping at the jambs and head, and replace anything that has gone stiff or torn. A door that rattles in the wind is a door that leaks.

Sliding glass doors deserve special attention because their tracks collect water. Make sure the weep holes in the track are clear, and consider a raised track or a track cover to keep driven rain from pooling against the interior threshold. Finally, do not forget the small penetrations: hose bibs, dryer vents, and exterior outlets. Each one should be flashed and sealed with a quality polyurethane caulk, not the cheap painter's grade stuff. On the coast, the details are the house. Get them right and your windows and doors will hold the line when the weather turns.