Guide
Fog-Belt Maintenance: Why Homes From San Francisco to Redwood City Need a Different Checklist
Daily fog does more to a house than inland sun does, just more slowly and less visibly, until a window won't shut or a caulk line turns black.
Windows and doors swell
Wood sashes and doors absorb moisture from the marine layer and bind in their tracks. Sanding the contact edge, sealing the raw wood, and using a dry lubricant fixes it for good in most cases. Replacing the window is rarely necessary.
Caulk fails faster
Bathrooms and window sills near the coast stay damp longer, so caulk breaks down and mildews in two to three years instead of four or five. Full removal and mildew-resistant silicone is the fix; new caulk over old never holds.
Paint cures slowly
Latex paint can take twice as long to fully cure in the fog belt. Second coats are spaced out, and furniture stays off the walls an extra day. Outdoors, painting starts once the morning dampness has burned off.
What's different inland
Mountain View, Sunnyvale, Santa Clara, and San Jose see much less of this. There the maintenance list is driven by heat — exterior paint drying too fast, fences cracking — and by hard water scaling up plumbing fixtures.
Questions people ask
How often should coastal bathrooms be re-caulked?
Every two to three years in the fog belt, versus four to five inland.
Why does my door only stick in winter?
Wood swells with the wet-season humidity. Planing the binding edge and sealing it stops the seasonal cycle.
Which cities are in the fog belt?
San Francisco, Daly City, South San Francisco, San Bruno, and the hill sides of Millbrae, Burlingame, and San Mateo, tapering off around Redwood City.