Can You Paint in the Rain

How Rain & Damp Surfaces Affect Paint

If it rains within one hour after painting a home’s exterior, rainwater will leave watermarks or wash away any paint that has not dried. Painting over a wet surface decreases paint adhesion and causes the paint to dry slower.

Weather conditions are a constant consideration when painting outdoors. However, strategically, painting in covered spaces is the best way to prevent unpredictable weather patterns from ruining wet paint. Looking at the weather radar is an excellent way to predict the potential for rain, enabling house painters to allow adequate dry times before an evening shower tappers in. 

Can You Paint When It’s Raining?

Painting in heavy rain or on surfaces that have accumulated moisture should be avoided, at all times, regardless of exterior paint. Although, some acrylic exterior paints dry and cure faster than others, enabling them to withstand rainwater sooner. 

The potential for damp or rainy weather is nothing new to house painters, as most exterior painting projects face these conditions. But knowing how to avoid getting caught in it will reduce the chances of the paint being negatively impacted.

Large overhangs on eaves and gable ends of a home provide covering and additional protection against rainwater. Light rain or drizzle is less likely to saturate siding and other areas directly underneath an overhang. Corner boards, window sills, and areas subjected to standing water will be affected the most by rain and should be painted, allowing ample time for the paint to dry before being exposed to excess moisture.

Painting During Rainy Seasons

Painting when there is rain or humidity in the forecast can be tricky. Some seasons and specific regions are more prone to rain showers, forcing painters to work around these conditions – otherwise, exterior painting wouldn’t be possible during these times. 

There are many tricks that professional painters learn over time to prevent painting over wet surfaces while still being able to continue paint production during wetter seasons. But paint colors, products, and weather significantly affect the chances of successfully painting when a storm is imminent. 

When painting darker colors, siding, horizontal surfaces, metal, or wood staining, the conditions should be as dry as possible.

Painting Before It Rains

Painting a dry surface with the potential for rain can be nerve-racking. Although, in our 20 years of experience, subtle paint degradation has been rare and never beyond repair. 

However, if the paint is exposed prematurely, it could suffer from weeping, known as “surfactant leaching.” So, just because the damage is not irreparable, it doesn’t mean it won’t cause a few completion delays and headaches. 

Furthermore, once dry, paint runoff can cause damage to other areas, such as roofs, driveways, and stained wood. So, painters should be cautious when painting above or near these areas when rain is forecasted.

Painting After It Rains

Applying paint too quickly after it rains can cause more issues than painting before it rains. Painting damp surfaces can cause bubbling and trap moisture in wood substrates, leading to wood rot and additional paint failure.

After a light rain, allow at least 4-12 hours of dry temperatures above 55 degrees and direct sunlight before continuing painting, allowing a minimum of 12- 24 hours after heavy rains. No brushing, spraying, rolling, or paint preparation should occur within 24-36 hours of pressure washing or after several days of heavy rain.

Using Oil-Based Paint in Wet Conditions

While oil-based paints are not water soluble, like water-based paints, they also suffer when applied in wet conditions. Conventional oil-based paints should never be painted over damp surfaces. 

Oil paints take longer to dry; therefore, more time is needed to plan around temperate weather conditions. Soya Alkyds, a raw material in these paints, will suffer from streaks and watermarks when exposed to rain before it dries.

Priming Over Wet Surfaces

Paint preparations such as priming, caulking, and puttying should also be avoided in the rain. Although paint is over 50% water and will damp surfaces, lower surface moisture will allow the solvent to penetrate better, taking raw materials and bonding agents deeper within the surface. 

Painting and preparing a dry surface promotes better adhesion, allowing the best durability without any adverse affects on each part of the painting process.

Painting Indoors When It’s Raining

The potential for leaking doors and windows will impact interior painting the most. Painting inside while it is raining will create subtle application changes under certain circumstances. Interior walls that join exterior walls will also take longer to dry. 

Interior paint dries slower when it’s humid or rainy outdoors as well. However, an increase in airflow will counter the affects of a rainy day on interior painting.

Conclusion

Just because there is rain in the forecast doesn’t mean the day is off-limits for house painting; it just means painters must know what they are doing and be cautious along the way. 

On the other hand, if water is dripping off your painter’s elbows and they are still painting, you may want to send them home.