How long does it take for mud to dry

I don’t know how many times I have come across this question. Plenty of times, I am guessing. It’s a great question and important to know. If you try painting before the mud is dry, you are just going to make a huge mess of the mudding job. To add to that, the mud needs to be sanded first and sanding wet mud is not recommended. 

How long should drywall mud dry before painting? The general rule of thumb is 24 hours for mud to dry before painting. The time required for mud to dry can differ from location to location. Drying time differs depending on humidity and air movement.  

24 hours was always given as the default amount of time for drywall mud to dry enough for sanding. In general, and most of the time, that works great. There are situations when less time is required, or more. In this article, I will go over why it might take longer for the mud to dry and things you can do to speed up the process if necessary. 

The Rule of Thumb for Drying Drywall Mud

Passed down from drywalling experts of past, it was always the ‘wait 24 hours between coats’ rule of thumb. In today’s fast moving world, that doesn’t always work. Either for the client or the tradesman. Sometimes the customer is in a hurry to get the job done and other times, the tradesman is busy and needs to finish up ASAP.  

Typically, if you mud a room and are done by noon and you go back the next day at noon, all of the mud should be dry. Then, you can apply another coat, if necessary, or start sanding. 

This rule of thumb works great if you have enough time to finish the job. But if you don’t, then we can look at ways you can speed things up. 

How to Dry Drywall Mud Faster?

There are three methods that will always dry mud faster. 

• Use a dehumidifier. Not everyone has one of these handy units but if you do, a dehumidifier can really help in drying out the mud. 
• Ventilation is very important for drying mud. The more air movement, the better. Having a fan running in the room helps quite a bit and if you add fresh air to the equation, it will help even more. Whether you have an air-exchanger going on high or a few windows open, both of these options will speed up the process. 
• Quick-set mud is another option. This mud is manufactured so it sets up and dries quicker than regular mud. This mud is great for jobs where you need to get in and out as quick as possible or you don’t want to make as many visits to the location. 

There is one con to drying mud quicker. When drywall mud dries fast, sometimes you end up with cracking in the mud. It happens and there isn’t much you can do about it if you speed things up too fast. It’s just something to be aware of.   

How Do I Know the Drywall Mud is Dry?

It is easy to identify wet drywall mud. Wet mud is darker than when it’s dry. Dry mud is white. 

As mud starts to dry, you can see where it is still wet vs dry. Usually more noticeable in inside corners, as they usually take longer to dry. 

You can test it as well by rubbing your finger across the mud. If the mud is smooth and powdery on the surface, it is dry. If it feels like your finger is sticking and rubbing the mud, then it’s still wet. 

Painting over Wet or Damp Drywall Mud [Good idea?]

If you can’t wait to paint, is it okay to paint over wet mud? I would never suggest doing this. If the mud is still wet, then you never sanded the mud. If you painted over non-sanded mud, you’re going to have edges showing and more. The job just won’t look good at all.  

Can I Dry Joint Compound With a Hair Dryer?

Sure, you could use a hair dryer. There is the chance though of the mud cracking because of the intense heat being blown onto the mud. If you can adjust the heat setting on the dryer, you might be able to avoid any cracking. 

I should mention that when drywall mud cracks from drying too quickly, it’s not really a problem other than now you need to apply more mud to cover the cracks. It’s just more work for you. 

How Long Does it Take for Skim Coat to Dry?

Skim coating is different than regular mudding. When you skim coat, you cover a larger area with a thin coat of mud. For example, if you have a rough plaster wall and want to smooth it out, you could skim coat the wall to fix. 

Skim coating might take longer to dry because of the added humidity of such a large area being covered. 

As with regular mudding, I would give any skim coating approximately 24 hours to dry. 

Drywall Mud Just Won’t Dry

I have been at some locations where it takes much longer than 24 hours to dry. Usually in basements and regions where humidity is high, most of the time. 

The best thing you can do is apply some of the methods listed above, especially the dehumidifier one. A dehumidifier will work best in humid regions for drying mud. 

If you just ventilate, you are allowing more humid air to enter the room. 

Conclusion

Just to reiterate a few things this article has covered. 

The general rule of thumb for drywall mud drying is a 24 hour period. Of course, this is an estimate and not an exact science. Use your better judgement. It is easy to spot wet drywall because of its darker shade than the dry areas. 

There are a few ways to speed up the process but watch out for drying too fast as it could create cracks in the mud. 

And lastly, don’t paint over met mud. Unless you just don’t care how the job looks. I am guessing you probably do care. So let it dry. Now, let’s get to work. Good luck!