How long exterior paint lasts depends on the surface, preparation, coating and exposure. A shaded wall and a sunny wall can age differently. These are the details to discuss before choosing a finish.
The south and west walls go first
Palo Alto gets about 260 sunny days a year. The walls that face south and west take most of it. Ultraviolet breaks down the binder in paint, the surface chalks, then it cracks. On a redwood-sided house we expect the south wall to want attention two to three years before the north wall.
The north wall has the opposite problem: fog. It stays damp into late morning, which means mildew and, on wood, slow rot at the bottom of the siding where water sits.
Stucco versus wood
| Surface | Typical life, good prep | What fails first |
|---|---|---|
| Stucco, elastomeric or acrylic | 12–15 years | Hairline cracks telegraph through; chalking on the sun side |
| Redwood or cedar lap siding | 8–12 years | Peeling at the lap joints, checking on the south wall |
| Eichler grooved plywood | 7–10 years | Edges and grooves, where water sits |
| Trim, fascia and window sills | 6–8 years | Horizontal surfaces, always |
The one thing that doubles it
Prep. Not a better paint, though that helps. The difference between a job that lasts six years and one that lasts twelve is whether every bare spot was primed, every joint was caulked, and the wash was given a full day to dry before the first coat. Paint over damp stucco and you have bought yourself a peeling problem that shows up in year two.
- Wash, then wait a full dry day. Fog mornings count against you.
- Prime every bare spot. Spot priming is not optional on wood.
- Caulk every joint that has opened. Water gets in at the joints, not the fields.
- Two coats. One coat is a color change, not a paint job.
What to do between paint jobs
Wash the house every couple of years with a garden hose and a soft brush. Keep sprinklers off the siding. If the south wall starts to chalk, call us: one recoat on one elevation is a small job and it resets the clock for the whole house.