How Long Does it Take for VOCs to Outgas from Paint?
March 27, 2018, by Debra Lynn Dadd
A client told me that after painting her home the smell has gone to a point where a normal person wouldn’t smell it, but she still reacts to the apartment after being there for an hour.
She sent me a great blog post I want to share with you INDOOR AIR NERD: How Long Does it take for VOCs to Dissipate?.
The writer of this post, who is a Professional Engineer who does air quality testing, notes that testing shows it can take 2-3 months for air quality to return to normal after painting.
But he also tells of a home where he measured the air quality and after almost seven months there were still VOCs present. His conclusion was that the VOCs still lingered because the house was built to be energy efficient and did not have mechanical ventilation.
To me, this really shows that the construction of the building can make a BIG difference in how long it takes for paint to outgas.
Things that can effect the rate of outgassing include:
insulation
“tight” construction (which decreases the natural air exchange found in older buildings)
mechanical ventilation (air exchanges from HVAC systems)
natural ventilation from the opening of doors and windows
Less ventilation means less reduction of VOCs. More ventilation means faster outgassing.
But the thing to remember is that the outgassing will continue until the paint or finish is completely CURED.
Paints and finishes go through a process of three phases:
“liquid” is a mixture of solids and particles and VOCs (if present). This allows you to apply the paint or finish to the surface
“dry to touch” happens within hours of applying the paint. You can touch it and it won’t come off on your hands and you can apply the next coat. But it is not completely dry all the way through.
“cured” means that all the liquid and VOCs have volatilized and there is only the solids of the paint left. At this point there should be no more outgassing. During the curing process the solid components in the paint contact and adhere to each other creating a continuous coating. When fully cured, you can wipe or wash the painted surface withoutharm, and the paint is no longer vulnerable to damage by water or chemicals.
Different types of paints take different periods of time to cure. You should find out and consider the cure time for any paint before you apply it. By doing so you will know what to expect in terms of how long it will continue to outgas VOCs or other chemicals.
You can check with the manufacturer of any paint to get the cure time.
I see most latex paints say it takes “up to 30 days for a ‘full cure,’” depending on color choice, humidity, ventilation and temperature.
Here are some tips from ECOS Paints on How to Make Paint Dry Faster
Keep a fan on. Multiple fans oscillating in the room will speed up the dry time considerably. You want to have a good amount of air circulation, but don’t have the fans on high if the room is dusty because it will ruin your paint finish.
Apply light coats. If you’re using a thicker nap on your roller sleeve, it might cause you to apply far more paint than what you need, increasing your dry time substantially. Two uniform coats of paint will always look better than one really thick one, so it’s best to apply light coats. You should feel your roller sleeve starting to dry out as you apply light pressure towards the end of a few rolling patterns. If the paint is squishing out of the sleeve when you apply pressure, you still have too much paint in the sleeve and should continue rolling before getting more paint from the tray.
Keep the room warm. If it’s winter and you’re painting in a space that gets a bit drafty, using a space heater is a good idea. Also, if it’s cold and your windows are leaky, that could affect how long the paint takes to dry near them. Some older homes that aren’t that well insulated can have fairly cold exterior facing walls. It’s still fine to paint them in the winter, but they might dry slower.
Keep the humidity down. When it’s really muggy in the summer, paint dries more slowly. Actually, just painting in a closed room increases the humidity even on a normal day, so open the windows if you can and get some fresh air in the room.
Paint one wall at a time. We always recommend this but, it’s easy to forget when you’re cutting in. If you cut in one wall and then paint it before moving on to the next, then that first wall might be dry by the time you finished the other three, so you’ll have no downtime during the project.
Use a zero-VOC* paint like ECOS Paints. Zero-VOC* paints naturally dry faster. Also, our rich pigments and premium formula cover better, so there’s less tendency to apply coats that are too thick.
Of course the best thing is to choose a paint with the least VOCs you can in the first place.
My favorite wall paint is Old Fashioned Milk Paint, which is made from milk and other natural ingredients, and has no VOCs. It actually smells like a mug of warm milk as you are painting it on the walls. But there are many other low- and zero-VOC paints available now as well.
If you like this article, please share it!
©NonToxU, 2020. All rights reserved.