How Do You Check if the Surface is Dry Enough (Moisture Testing) Before Painting?

Why Moisture Testing Before Painting is Essential

Moisture beneath a painted surface can lead to costly issues. Here’s why it should never be overlooked:

• Causes poor adhesion, leading to bubbling and peeling

• Encourages mold and mildew growth, especially on drywall

• Compromises the finish, reducing the lifespan of the paint

• Can damage the underlying structure if left untreated

At Pileggi Painting, we make sure every surface is dry before painting. It’s part of our professional preparation process, whether we’re painting interiors, exteriors, or commercial properties in the Kansas City area.

Common Problems Caused by Painting Over Moist Surfaces

Many property owners assume that once a surface feels dry, it’s ready to paint. Unfortunately, that’s not the case.

Here's what can go wrong:

• Paint Blistering: Moisture trapped under paint expands and forms blisters.

• Peeling and Flaking: Paint loses adhesion when moisture breaks the bond between the wall and coating.

• Discoloration or Stains: Damp areas may cause the paint to discolor over time.

• Mold Growth: Especially in basements, bathrooms, or recently flooded areas.

To avoid these issues, moisture testing is a must.

Sherwin-Williams Guide to Paint Failure Causes

Best Methods to Test for Moisture Before Painting

There are several ways to ensure your surface is dry enough for painting. Some are DIY-friendly, while others require tools used by professionals.

1. Plastic Sheet Method (DIY)

This method is simple and effective, especially for concrete or masonry:

• Tape a 12x12 inch sheet of plastic to the wall or floor.

• Seal the edges completely.

• Leave it for 24 hours.

• If moisture appears inside the plastic, the surface is not dry.

This test is often used before applying floor coatings or masonry primers.

2. Moisture Meters (Professional Standard)

Moisture meters are the most reliable tools for testing surface moisture in drywall, wood, and masonry. These come in two types:

• Pin-type meters: Insert pins into the material to measure electrical resistance.

• Pinless meters: Use sensors to detect moisture without damaging the surface.

Pileggi Painting uses commercial-grade meters for accurate results. For drywall and wood, moisture should typically be below 15% before painting.

Recommended Product: Wagner Meters Pinless Wood Moisture Meter (Home Depot)

3. Infrared Thermometers

These are used to detect temperature differences that may indicate hidden moisture. Ideal for checking larger areas or behind surfaces, such as insulated walls.

Learn More: Using Infrared for Moisture Detection – FLIR Systems

Surfaces That Require Moisture Testing

Some materials retain moisture more than others. Always test the following before painting:

• Drywall: Especially after flooding, leaks, or in humid areas.

• Wood Trim and Siding: Wood absorbs and releases moisture slowly.

• Concrete and Masonry: These materials take longer to dry and are prone to trapping moisture.

• Stucco Exteriors: Porous surfaces that absorb ambient humidity.

For Kansas City homes, moisture testing is especially important for basement walls and exterior siding, which are often exposed to fluctuating weather.

How Kansas City's Weather Impacts Drying Time

Kansas City’s climate features cold winters, humid summers, and plenty of rain in between making moisture testing even more critical.

• Humidity Delays Drying: High humidity slows down the drying process, even if surfaces feel dry.

• Rain and Storms: After a storm, surfaces can remain damp for days.

• Temperature Drops: Low temperatures can cause moisture to settle and increase drying time.

Pileggi Painting schedules exterior painting jobs around local weather patterns. We also allow extra drying time after rain or power washing.

Exterior Painting Services in Kansas City

Common Mistakes to Avoid with Moisture Testing

Even if you’re planning to paint on your own, knowing what not to do is just as important:

• Skipping moisture testing entirely

• Painting shortly after pressure washing or rain

• Ignoring shaded or poorly ventilated areas

• Using faulty or low-quality moisture meters

• Painting over visible water stains or mold

Always be sure the surface is clean, dry, and primed before painting.

FAQs About Moisture Testing and Painting

How long should I wait to paint after rain?
At least 48 hours, depending on humidity and sunlight exposure. Concrete and stucco may require longer.

Can I paint over drywall after a water leak?
Only after using a moisture meter to confirm it’s completely dry. You may also need to treat for mold and mildew first.

Do I need a professional to test moisture?
For small DIY projects, basic methods may work. But for full-house painting or exterior jobs, hiring a professional like Pileggi Painting ensures no corners are cut.

Does Pileggi Painting include moisture testing?
Yes. We include moisture testing as part of our surface preparation process to ensure every paint job is built to last.

Request a Free Quote from Pileggi Painting

Moisture testing might sound like a small step, but it’s one that can make or break your paint job. Whether you're updating your interior, refreshing your exterior, or tackling a complete home renovation, Pileggi Painting ensures every surface is prepped the right way.

We don’t just paint we prep like pros.

Get started today. Request a free quote from Pileggi Painting and protect your home with a finish that lasts.