Why Low Moisture Content Is Crucial for a Long-Lasting Paint Job

Why Low Moisture Content Is Crucial for a Long-Lasting Paint Job

If you want a paint job to last, pay attention to the humidity levels. Humid air has more moisture, which can lead to a wide range of problems when painting indoors or outdoors.

How Moisture Content Damages Your Paint Job 

Moisture causes paint to evaporate at a slower rate, which increases the drying time. This becomes more of a problem in cold weather, as the colder temperatures cause the paint to thicken. 

Paint dries within a few hours of application in normal situations but takes up to 30 days to completely cure. Increasing the drying time leaves the paint more susceptible to damage. Potential issues include:

• Paint lifting
• Adhesion failure
• Surfactant leaching

High humidity levels cause acrylic paints to absorb more water vapors, which increases the moisture content of the paint. High moisture content may cause paint to lift. It may start to shrivel, swell, or wrinkle.

High moisture content can also cause adhesion failure. Poor adhesion allows the paint to crack and peel, which significantly decreases the longevity of the paint job.

High humidity levels may also cause condensation to form on the surface of your paint job. The condensation can cause a problem called surfactant leaching. The water leaches water-soluble parts of the paint, resulting in brown streaks on the surface of the paint. 

How to Avoid Moisture When Painting Indoors

If possible, try to avoid painting during periods of high humidity. Rainy weather and warm, humid summer days can increase the humidity inside and outside the home. 

Everyday activities can also add moisture to the air inside. Cooking, using a washing machine, showering, and even breathing can contribute to the humidity level. Limiting some of these activities, especially in the areas where you plan to paint, can help limit moisture.

Running a dehumidifier or an air conditioner can also remove moisture from the air. AC systems also help circulate air, which can help combat moisture and aid the drying process.

A furnace also circulates air and may create drier conditions in the winter, as the air outside is often less humid. However, heating does not remove humidity. It allows air to hold even more moisture. Running a furnace in humid conditions can make the problem worse.

How to Avoid Moisture When Painting Outdoors

Remember to avoid painting during rainy weather and humid seasons. You should also check the weather forecast. 

Look for a period with cooler weather and less of a chance of rain. Cooler weather often results in lower moisture levels. However, you should avoid painting when it is too cool.

Temperatures in the high 60s and low 70s should allow you to recoat every four to five hours. Temperatures in the 50s may require you to wait six hours or longer between coats. 

Start early in the day on the east-facing side of the house. Work your way around the south, west, and north sides of the house throughout the day to keep the sun moving along with you or just behind you. 

Throw a tarp over the paint job if you expect rain overnight. Protecting the paint from additional moisture until it dries increases the chances of a long-lasting paint job.

Along with these suggestions, you should avoid applying too thick of a coat. A thicker coat increases the drying time and the ability to hold more moisture.