If you’ve just finished applying a coat of drywall mud to your drywall joints or completed skim layers, it is tempting to start right away on the next steps to complete the job.
But before you get too carried away, waiting the appropriate amount of time between applying your joint compound and painting is crucial if you want to avoid re-doing all of your hard work.
A commonly used rule of thumb is to wait at least 24 hours after applying drywall mud to prepare the wall for painting. However, in reality, several factors contribute to either slower or faster dry times, including humidity, temperature, the thickness of mud, and the type of mud.
The most important of these are the factors slowing down the drying process since the drywall mud needs to be completely dry before sanding, priming, and painting.
The rest of this post will give you detailed information on why and how long your drying times will vary and tips to cut down on drying time.
What Factors Affect Drying Time For Drywall Mud?
Applying a coat of paint over wet drywall mud can cause significant shrinkage of the joint compound.
To avoid this issue, it’s essential to understand the key factors impacting your drywall mud dry time.
The following list covers the most critical factors contributing to dry time:
- Ambient temperature
- Air movement/ventilation
- Coat thickness
- Product temperature/type
The drywall dry time can vary greatly, depending on these factors.
Although the 24-hour rule of thumb for drywall mud is a good place to start, the dry time may take up to 3 days for thick coats of drywall mud or up to a week in basements in a humid climate.
The ideal temperature for applying joint compound is 65 – 80° degrees Fahrenheit (27° C).
The drying time will be longer at colder temperatures, and it is not recommended to use joint compound below 55° degrees Fahrenheit (13° C).
If it takes too long to dry, the edges of the drywall panel will soften.
Higher environmental temperatures will reduce the drying time.
However, drying too fast can cause the joint compound to crack, so while completing a drywall project in summer might be more efficient, extremely high temperatures pose a risk of cracking.
Areas with good air movement and ventilation will require less time to dry.
For example, a ground-level area with open windows and fans will dry faster than a basement or other rooms with less air circulation.
The ideal humidity range for working with drywall compounds is 20-40%.
A more humid environment will take more time for the drywall mud to dry before you start applying coats of paint.
The humidity will vary depending on the climate and what area of the building you are working in (e.g., ground-level vs. basement).
Applying thinner coats of drywall mud will reduce the drywall dry time significantly.
This same rule for drywall applies to painting as well– apply thin coats of paint and wait at least 24 hours between coats.
Certain types of drywall compounds are designed specifically for a quick curing time.
Hot drywall compounds generally dry much faster than the more common types.
Hot joint compounds dry in as little as 20-60 minutes.
The downside of this type of product is the need the work quickly.
The fast drying time is convenient, but it does not leave much room for error and has less workability.
On the other end of the spectrum, actual plaster takes much longer to dry than drywall mud.
Plasters will generally give you plenty of time to get the thickness of the coat just right, but plaster also takes days or weeks to dry.
In addition, the pre-mixed joint compounds will take longer to dry than the dry mixes you mix up yourself.
How Can I Reduce The Drywall Mud Drying Time?
If you want to make sure you have a quality finished product but need to speed up the process a bit, here are some strategies often used in the drywall business:
- Use a dehumidifier, fan, or open window to increase ventilation
- Apply thin layers of drywall mud from the beginning
- Use a hot joint compound or another quick-setting joint compound
Another option, in a pinch, is to use a heat gun or a hairdryer.
These are more suitable in cases where you are doing a drywall patch-up job rather than a whole skim coat or larger areas.
However, drying the joint compound too fast also causes it to crack sometimes, so it is a bit riskier to use a strong heat source.
Using a hairdryer on the cool or low setting is a safer alternative.
Pro-tip: Quality work requires patience, so don’t rush it if you don’t have to.
Waiting for mud to dry is one of the reasons it takes days to do drywall (click to learn what else goes into it).
How Do I Know If My Drywall Is Ready To Be Painted?
To prepare your drywall for painting, use the following steps to make sure you have properly prepared the drywall sheets:
- The joint compound should be solid to the touch. If you touch the joint compound gently and it does not give way or smear, it is dry enough to proceed with the next steps. Look for any darker spots as an indicator of wet drywall mud.
- Check the drywall for nicks or gouges once you have confirmed the surface is dry.
- If there are any rough spots in the drywall sheets, fill them with joint compounds and wait for these spots to be dry to the touch. This step is important to remove any drywall imperfections before being sealed with primer.
- Next, sand the drywall surface to make sure the drywall joint compound is completely smooth. Using a pole sander will make this step easier.
- Use a cloth to wipe off the drywall surface and remove any drywall dust remaining after sanding. Eliminating the drywall dust will help the primer stick better to the drywall before painting.
If you get drywall dust on your painted walls, it’s a huge pain.
Check out our article for help on how to take care of this.