Been looking forward to painting but the weather just isn’t cooperating? We know how tempting it is to add those pops of color you’ve spent a lot of time picking. But to achieve a finish that is both beautiful and long-lasting, you’ll want to find a suitable time and condition to paint.
Painting in humid weather causes paint to dry slowly, resulting in a gunky, tacky surface. To paint under low humidity levels, on the other hand, is tricky since it makes it difficult to spread the color since the paint dries too rapidly, leaving you with a patchy finish that needs to be redone.
But still, perfect painting conditions can be difficult to come by depending on the time of year. And, in reality, you can still paint in humid weather. You just have to know the limitations, which type of paint to use, and take the necessary precautions.
In this post, we’ll talk about the ideal humidity level for painting. We’ll also discuss the risks of painting in high humidity and what you can do to combat moisture’s damaging effect on your painting project to help you achieve a beautiful and professional-looking finish.
The Ideal Humidity Level for Painting
The ideal humidity level for painting depends on the type of paint you use. As a general rule, the optimum humidity level for painting is between 40 and 70%. An 85% humidity level is still acceptable, though anything above that range will cause the paint to dry slowly.
Imagine drying clothes when there is high humidity. Since there’s already a high level of moisture in the air, your clothes won’t dry as quickly as you’d want.
The same thing goes with paints, especially water-based latex paints. Such paints contain water and solvent. When there is a high level of moisture in the air, the water content in the paint evaporates a lot slower, which affects drying time.
One thing to keep in mind is that the water in your paint needs to dry faster than the solvent to achieve a flawless finish.
But you shouldn’t paint under low humidity levels, either. You’ll want the painted surface to dry properly, not too quickly. This is especially crucial when painting dark surfaces with bright colors. If the paint dries too fast, it can get difficult to smooth out brush strokes. This results in patchy surfaces that need to be redone.
Alright. But how about an oil-based paint?
It doesn’t matter which paint you use. You’ll encounter the same issues as latex-based paints, whether the humidity is high or low.
What Is the Ideal Temperature for Painting?
Different paints have different formulas, which can influence the application and drying process. You should avoid working with oil-based paints if the temperature is expected to drop below 45°F within two days. For temperatures above that range, it’s best to use water-based latex paints.
However, keep in mind that doing your paint job in extremely low temperatures can thicken the coatings, which results in longer drying times. Lower temperatures can also slow down curing.
That said, you’ll want to avoid applying oil-based paints above 90°F and latex paints when the temperature exceeds 85°F. With such high ranges, these paints will struggle to bind properly. You can always check the manufacturer’s defined range of acceptable temperatures for your paint.
It’s also best to check the weather forecast. You’ll want to avoid rainy or windy weather conditions as these can cause flaws in painted surfaces. Rain, in particular, can significantly impact your painting job. The paint may need up to 8 hours to dry before it rains. This gives the paint enough time to bond with the surface.
How Humidity Affects Paint Job
Humidity may significantly impact the final result of a paint job. Here are some of the common problems you may encounter:
Mold thrives in warm, damp areas. So, if your walls are moist and the relative humidity is regularly above 70%, it can create a good condition for mold growth. They can grow between the wall and the paint. Mold growth can also lead to peeling, discoloration, and deterioration on the surface.
Lengthy Drying Times
When it comes to drying times, the water content in your painting should dry as fast as the solvents if not faster. It’s a race between those two elements here. If the solvent dries before the water, the paint will not produce a solid surface. Drying is especially crucial for interior painting.
This can happen when you paint in high humidity. The moisture level in the air will keep the water in the paint from evaporating fast. When your painting dries slowly, it can result in sagging and dripping of the paint.
In addition, the paint will stay wet and sticky for a longer period of time. This is why you’ll notice a gel-like texture on the painted surface. And when the humidity falls, it creates a wavy pattern, leaving you with results you don’t want. Plus, the painted surface will be prone to damage.
Swelling Surfaces on Wood
Woods are hygroscopic materials, which means that they absorb moisture in the air. When this happens, the wood will expand.
Painting under high humidity isn’t suitable since the wood swells after you layer the paint, especially when you apply it too thickly. That swelling will likely result in warping, chipping, and cracking on the painted surface.
Effects on Metal Surfaces
Think metal surfaces are hard to paint? Well, think about painting them under high humidity. The amount of moisture in the air can affect the ability of the paint to adhere to metal surfaces. This can result in longer drying times, resulting in a tacky finish and it may invite dust and debris to stick to the painted surface.
Another thing to note is that, when you’re painting metal surfaces in humid conditions, bubbles may form and you’ll have a hard time spreading the paint evenly. It can lend a blotchy look to your metal surfaces.
Painting in High Humidity? No Problem!
The optimum relative humidity for painting is between 40-70%. While we do not recommend painting above that humidity range, here are a few tips and tricks you can take if you must tackle the job right away.
Check Moisture Level on the Surface Before Painting
This is especially a crucial step if you’ll be painting on wooden surfaces. Remember, wood absorbs moisture in the air.
Before you begin painting, check if the surface is wet or damp. For uncoated wood, you can scuff-sand an area and see if you can easily blow away the wood dust. If not, then there’s probably a lot of moisture in the wood. In this case, you need to let it dry first.
If you intend to paint on a non-wood surface like concrete or metal, simply press a cloth against it to see whether there is any presence of moisture.
Dry the Surface Before Painting
For damp wood surfaces, you need to give them enough time to dry. But if you’re painting a surface that has been washed off, grab a dry cloth or towel to soak up any excess water. Let the wall dry by ventilating the area. Open your windows, use a fan, or if you have an industrial blower, that should help too.
Take Advantage of the Sun
Not for drying your paint, but for warming up uncoated surfaces and getting rid of moisture. The best time to do this is early in the morning. This preps your clean surface for that fresh coat of paint.
After allowing the surfaces to soak up the sun, let them cool down in the shade, and don’t start painting right away. Make sure not to put the painted surface under direct sunlight.
Wait It Out
Find the right time of the day when it is suitable to paint. What does it feel like throughout the day? Do the temperature rise and the humidity drop by mid-day? Is it humid by late afternoon? It’s crucial that you take note of the heat patterns.
In general, it’s always best to paint in the morning as the temperature rises by midday. Depending on where you live, it may get warmer as time passes. So, paint before the sun hits its peak temperature. We recommend looking at the weather forecast so you can plan ahead.
Start With Thin Coats
Application is important when painting in humid weather. If you apply thin layers, the paint will dry faster and cure properly. It’s laborious but you’ll be satisfied with the final results.
Control Humidity Levels
This is only possible when you’re painting in an enclosed space like your garage, workstation, or any room in your house. To control the humidity levels in the space, invest in a dehumidifier. Your HVAC system, windows, and fans will also do the trick. If you can, install a hygrometer to keep track of humidity levels in your home.
Will Paint Dry at 90% Humidity?
Paint doesn’t do well in high humidity. When humidity levels hit 70%, the paint will dry too slowly. If the humidity reaches over 85%, the paint becomes sticky, cloudy, or may form bubbles or cracks. This will extend the drying time for several days.
What Is the Best Temperature and Humidity for Painting?
The ideal temperature to tackle a painting job is between 40°F and 90°F. When it comes to humidity, it should be kept between 40 and 70%. Such conditions allow smooth application and faster drying time.
How Do You Control Humidity When Painting?
There are several ways to control humidity for better painting conditions. A dehumidifier can help eliminate excess moisture from the air. This helps your painting dry faster.
Air conditioning systems can also help to lower humidity levels in your space and offer a more pleasant environment for painting. You can open your windows, use fans, or install a ventilation system to help circulate air in your workspace.
Ready To Paint?
Now that you know what the ideal humidity level for painting is, it’s time to put that painting skills to use!
Remember, to achieve the desired outcomes, find the best time of day to paint while keeping the humidity level between 40 and 70%. But, if the humidity level exceeds that range and you find yourself needing to paint anyway, make sure to take the necessary precautions to keep the mishaps to a minimum.
If you have any questions about the topic, let us know; we would be happy to help you. Good luck!