For a stucco or painted block house in Miami, wash the walls first, let them dry for at least 48 to 72 hours (longer after rain or in summer humidity), and only then prime and paint. Skipping the wash traps dirt and mildew under the new coat, and painting too soon traps moisture, which is a common reason fresh paint blisters or peels. Local painters and paint manufacturers give slightly different drying times, so the technical data sheet on the paint can is the final word.
Why the wash matters before a repaint
Paint sticks to a clean, sound surface. On South Florida exteriors the surface is rarely clean: chalky old paint, a film of salt and dust, green or black algae streaks, and mildew in the shaded north and east walls. A coat applied over that film may look fine for a few months and then lift in sheets. If you are still deciding whether the walls need paint at all, our guide to mold, mildew and algae on exterior surfaces explains what the stains are and how they are treated.
Choose the method for the wall
Most painted stucco does not need a hard blast. High pressure can gouge the surface, drive water behind the finish and open hairline cracks. Many contractors prefer a low-pressure wash with a cleaning solution for growth, followed by a rinse. The trade-offs are covered in soft wash vs. pressure wash. Published pressure suggestions for stucco vary from source to source, and several warn that too much pressure causes damage, so start gently and test an inconspicuous spot.
| Wall condition | Usual approach | Watch for |
|---|---|---|
| Light dust and salt film | Low-pressure rinse, wide fan tip | Water forced up under window trim |
| Green or black algae and mildew | Cleaning solution with a dwell time, then rinse | Plants, pool water and runoff; see below |
| Chalky or peeling old paint | Wash, then scrape or sand loose areas by hand | Lead paint on older homes |
| Cracked stucco | Wash, repair, let patches cure, then prime | Patching compound needs its own cure time |
How long to wait before painting
Florida contractor guides commonly cite 48 to 72 hours for stucco, with 24 hours as the earliest realistic window and several days or more in the summer rainy season. These are rules of thumb, not standards. Stucco is porous and can feel dry on the surface while holding moisture inside, so a quick touch test is not reliable.
- Check the paint label. Manufacturers state the surface conditions their product needs, and those override a painter's habit.
- Use a moisture meter if you can. Contractor sources cite targets of roughly 12 to 15 percent for masonry before priming; confirm the number your paint maker accepts.
- Watch the forecast. A wall that dried for two days can be soaked again by an afternoon storm.
- Allow time for repairs. Patches in cracked stucco usually need extra cure time before priming, so schedule the repair before the final dry period.
Pre-1978 homes and lead paint
If the house was built before 1978, the old paint may contain lead. Federal rules under the EPA's Renovation, Repair and Painting program apply to paid contractors working in pre-1978 housing when they disturb more than 20 square feet of exterior painted surface, and they require certified firms and lead-safe work practices. EPA states that pressure washing is not itself a prohibited practice under the rule, but it is subject to the same containment requirements as other work. The listed prohibited practices include open-flame burning and machine sanding without HEPA exhaust control. A homeowner working on their own residence is generally outside the rule, though sensible precautions still apply. Read EPA's work practice FAQ before scraping or sanding old paint, and ask any contractor whether the firm is lead-safe certified.
Water, runoff and neighbors
Miami-Dade's year-round watering restrictions, according to the county's water conservation page, exempt pressure cleaning of paved surfaces, but the water still has to go somewhere. Cleaning solution and paint chips should not end up in storm drains; see our overview of Miami-Dade wash water rules. Water shortage conditions can change, so check current county or water management district notices before a big job.
Condo and HOA buildings
In an association, the paint color, schedule and sometimes the wash method are decided by the board or the documents, not the individual owner. If your building is repainting, HOA and condo exterior cleaning rules explain who normally arranges and approves the work.
A sensible sequence
- Inspect the walls for cracks, loose paint, failed caulk and moisture sources such as sprinklers and downspouts.
- Cover plants, protect windows, outlets and light fixtures.
- Wash from the top down and rinse thoroughly.
- Repair cracks and loose areas; let repairs cure.
- Confirm the walls are dry through, then prime and paint within the paint maker's recoat window.
Costs and hiring
Many painters include a wash in their quote, while others expect the owner to arrange it separately. Ask which applies and get it in writing. Price depends on wall area, height and access; typical ranges are in our cost guide, and any figure should be verified with the provider.
Frequently Asked Questions
How long should stucco dry after pressure washing before painting?
Florida contractor guidance commonly points to 48 to 72 hours, longer in humid or rainy weather. Follow the paint manufacturer's data sheet if it says otherwise.
Do I have to wash the house before repainting?
In practice, yes. Paint bonds poorly to dirt, chalk and mildew, and most paint makers call for a clean surface.
Can high pressure damage stucco?
It can. Excess pressure can erode the finish, open cracks and push water behind the wall, so lower pressure or a soft wash is often preferred.
Is pressure washing allowed on a pre-1978 house?
EPA says pressure washing is not a prohibited practice under its lead rule, but certified contractors must follow containment requirements when disturbing painted surfaces above the threshold.
Does the wash water have to be contained?
Keep cleaning solution, paint chips and sediment out of storm drains and canals where possible, and check current local rules before the job.