Interior paint is chosen for how a room feels. Exterior paint is chosen for how it survives — sun, fog, rain and fifteen years of the wall moving underneath it. The color is the easy part. What matters is matching the paint to what your walls are actually made of.
Before anything else, identify the substrate. It decides the product, the prep and the price.
Get this wrong and no amount of good paint saves the job. The single most expensive mistake in exterior painting is using a stucco product on wood.
For most Bay Area houses, 100% acrylic exterior paint is the right answer. It bonds well, resists UV, flexes with temperature swings, and — critically — it breathes, letting moisture in the wall escape outward. Expect roughly 8 to 12 years from a quality acrylic, properly applied.
Elastomeric is the thicker, rubber-like coating. It builds a much heavier film that bridges hairline cracks and effectively waterproofs a wall, and it can run 10 to 15 years. On cracking stucco where water intrusion is the problem, it is the better tool.
But it comes with one rule that is not negotiable:
Exterior paint fails from the wall outward, not the can inward. When a repaint peels in three years, the cause is nearly always what happened before the first coat went on.
If a bid looks unusually cheap, prep is where the hours were removed. It is also the half of the job you cannot see once the paint is on.
Indoors, sheen is a trade between washability and hiding flaws. Outdoors it is mostly about durability and how much you want the sun to reveal:
The interior logic is the same underneath, and it is covered wall by wall in our interior paint sheen guide.
Two local realities should shape the color before taste does.
Then test properly: paint large samples on two different elevations and look at them morning and late afternoon. Exterior color shifts far more between direct sun and shade than any chip suggests.
Exterior painting of a single-family home or duplex is exempt from building permits in California: Section R105.2 of the California Residential Code lists painting among the finish work that needs no permit, the same as painting inside. That is the easy part.
What a permit exemption does not override:
One phone call before you buy paint settles all three. If you are painting to sell, our guide to pre-sale fixes that need no permit covers where exterior paint sits in the wider list.
For a single-family home or duplex, no — Section R105.2 of the California Residential Code lists painting among the finish work exempt from a building permit, the same as interior painting. What a permit exemption does not override is a homeowners association's approval process or a historic district's design review, where your property is subject to them, and larger multi-unit or commercial buildings can still need planning approval in some cities. One call to the city or the HOA before you buy paint settles it.
Acrylic for most stucco, elastomeric when cracking and water intrusion are the real problem. A quality 100% acrylic breathes, resists UV, and gives roughly eight to twelve years — and it is cheaper and easier to recoat. Elastomeric builds a much thicker, rubbery film that bridges hairline cracks and effectively waterproofs the wall, typically lasting ten to fifteen years, but it only works over a surface that is sound, clean and dry, and it makes the next repaint harder.
No, and this is the costliest exterior paint mistake we see. Elastomeric does not bond properly to wood, and because the film does not breathe it traps moisture behind it. Wood siding has to be able to dry outward; seal it under a waterproof membrane and you get mildew and rot rather than protection. Wood siding wants a breathable 100% acrylic over the correct primer.
Roughly eight to twelve years for a quality 100% acrylic and ten to fifteen for elastomeric on stucco — but only with real preparation behind it. Two local factors move those numbers: strong UV on south and west elevations shortens the life of dark colors, and the foggy side of a house weathers differently from the sunny side, so one elevation often needs attention well before the rest. Paint failing in three or four years is a prep problem, not a product problem.
Flat or low-lustre on the body, satin or semi-gloss on trim, fascia and shutters, and semi-gloss or gloss on the front door. The flatter body hides stucco patches, siding texture and the waves in an older wall, while the shinier trim is more washable and creates the contrast that makes a paint job look crisp from the street.
Yes — painting intact asbestos cement siding is the standard recommendation, and it is common on Bay Area homes built before about 1980. Asbestos is dangerous when fibres are released into the air, so the rule is simple: do not sand, grind, power-wash aggressively, scrape or cut it. Wash it gently by hand, prime and paint. Sealing it under fresh paint is a recognised way to keep it stable. If any of it is already broken, crumbling or has to be removed, stop and bring in a certified asbestos contractor — testing first is inexpensive and settles the question.
Almost always preparation, not the paint. The common causes are painting over dirt, chalk or mildew so the coating never bonded; skipping the right primer, particularly on alkaline stucco or bare wood; painting a wall that was still damp; or spreading the paint too thin to build proper film thickness — a frequent failure with elastomeric. Moisture pushing out from behind is the other big one, which is why breathable acrylic belongs on wood.
Late spring through early autumn, when walls are dry and overnight temperatures stay within the manufacturer's range. Coastal fog matters more than people expect: a wall that looks dry at noon can hold overnight moisture, and paint applied over damp stucco or siding is a peel waiting to happen. A good crew checks the surface, not just the forecast.
