If your Florida home’s paint is bubbling or blistering, you’re looking at a failure in adhesion—usually caused by moisture, heat, or coating incompatibility. In Pinellas County, sun strength, humidity, salt air, and afternoon storms make bubbling far more likely if prep and timing aren’t perfect.
This guide explains the real causes, how to diagnose the issue, and the Florida-specific fix so your repaint lasts.
What Causes Exterior Paint to Bubble in Florida
- Trapped moisture: Painting over damp stucco/wood, high substrate moisture, or water intrusion at joints and windows.
- Heat/sun blistering: Painting hot elevations or near the dew-point window; the top film skins while solvents/water under the surface expand.
- Poor surface prep: Chalk, mildew, cleaner residue, or glossy spots prevent bonding.
- Incompatible layers: Waterborne over failing oil/unknown coatings without proper primer; elastomeric over damp walls.
- Pressure washing mistakes: Forcing water under laps or into stucco cracks, then painting before full dry.
Fast Diagnosis: Moisture or Heat?
- Location pattern
- South/west walls, siding above dark masonry, or metal doors in sun = heat/sun blistering likely.
- Lower walls, around windows/doors, near grade, or shaded sides = moisture likely.
- Cut test
- Score an “X” through a bubble. If water or dampness appears or the substrate feels cool/wet, it’s moisture-driven.
- Moisture readings
- Wood trim/fascia should be ≤16%.
- Stucco/masonry should be at or below the primer manufacturer’s spec (often ≤12% equivalent).
If higher, let it dry and find the intrusion source.
Florida-Correct Fix (Step by Step)
1) Soft Wash & Rinse
Remove chalk, dirt, salts, and mildew. Avoid high PSI that drives water behind laps or into cracks. Rinse clean.2) Dry Window
Allow 24–48 hours in normal conditions; 48–72 hours for shaded/coastal sides. Confirm with a moisture meter—don’t rely on “looks dry.”3) Open, Scrape, Sand
Open bubbles, scrape to sound coating, feather sand edges, and remove dust. Cut out failed caulk and clean residues around joints.4) Solve the Source
Seal hairline stucco cracks with elastomeric patch; re-caulk window/door perimeters with a high-quality, paintable sealant (no silicone on paint paths). Correct sprinklers or irrigation hitting walls. Ensure gutters/flashings are functional.5) Prime Intelligently
- Chalky/aged stucco: Acrylic chalk-binding masonry primer.
- New/high-pH stucco: Alkali-resistant masonry primer.
- Wood/trim: Exterior stain-blocking/bonding primer as needed.
- Unknown/old enamel layers: Bonding primer after scuff-sand.
6) Two Uniform Finish Coats
Use a premium 100% acrylic exterior (or high-build acrylic system for hairline cracking). Spray-and-backroll to press paint into stucco pores. Maintain a wet edge.7) Stage by Elevation
Coat sun sides when they are not in direct, hot sun. Keep surface temperature well above dew point and avoid late-day painting that sees overnight re-wetting.Quick Selector: Bubble Cause → Correct Response
Symptom Likely Cause Fix Bubbles concentrated on south/west walls or metal doors Heat/sun blistering Paint earlier in day, lighter colors, two thin coats; let coats flash off fully Bubbles near windows/doors, lower walls, shaded sides Moisture intrusion Re-caulk, patch stucco, allow full dry window, moisture-checked, prime appropriately Bubbles over chalky, dusty surfaces Poor prep/chalk Soft wash, chalk-binding primer, two coats Bubbles over unknown glossy/old paint Incompatibility Scuff-sand, bonding primer, compatible acrylic topcoat Bubbles after pressure wash Water trapped Extend dry time 48–72 hrs; verify readings before priming/coating
Timing & Weather Windows (Florida Reality)
- Paint when surface temp is 5°F above dew point and rising.
- Recoat windows run longer in humidity—respect the data sheet (often 4–6+ hours).
- Best exterior season: October–April for faster dry and fewer rain delays.
Color & Sheen Choices That Help
- Painting the morning after a late-day wash on shaded stucco
- Skipping moisture checks on wood trim/fascia
- Using silicone around paint paths
- Heavy one-coat applications that skin over
- Painting in direct hot sun or too close to the dew-point window
Color Strategy for Florida Vinyl
- Body walls: Same or lighter than existing unless using vinyl-safe formulas
- Accents: Deeper tones on shutters/doors (satin) for depth without heating large surfaces
- Neighborhood fit: Keep coastal palettes sun-washed (slightly grayed) to reduce glare and fade
How Legacy Prevents Bubbling
At Legacy Applications, we meter substrates, repair intrusion points, specify the right primer for each elevation, and pace application around Florida’s sun and humidity. The result is a finish that bonds correctly, looks elegant, and lasts.
Book your free consultation today and get a moisture-safe, Florida-proof repaint plan for your Pinellas home.