I'm not quite sure how much drywall mud I'll be using for my upcoming project so I'm planning to buy a box of it. Assuming that I have some left over, is there a technique for not wasting it? Will it last for awhile if I make sure to tie up the bag again and close the box lid? Or should I assume that it'll only last for a short time after I initially open the box.

Also, what's the shelf life for drywall mud? Should I only buy as much as I think I need? Or if I found a good deal, will it keep for awhile (for use with other projects later)?


5 Answers 5


I don't have any experience with boxes, but have quite a bit with the 5-gallon buckets of compound. Without knowing much about how those boxes seal, I'd recommend going with a bucket- the buckets/lids seal air tight which is important for keeping the mud from drying out. The other thing I'd recommend- every time you close the box or bucket, put a piece of plastic sheeting over the top of the mud. This traps the moisture in against the mud, and prolongs its shelf life. The buckets come with a round piece of plastic sheeting on top of the mud- I just fold it in half (to keep any bits of mud stuck to the plastic from being exposed to air) then when I am done for the day, unfold it, and put it back on top of the mud in the bucket.

  • 1
    I second the bucket recommendation; it'll be about the right consistency when you open it.
    – Niall C.
    Oct 25, 2010 at 17:00
  • 1
    When I built my son's nursery I bought the 1 gal buckets (I could only work a couple hours a day and had no idea how much mud it would take - answer: ~ 15 gals ) and once I had four collected I bought the 3.5 gal box of premix and divided it up into my buckets. I recently pulled out a bucket of over a year old mud and it was fine with a little water. Oct 25, 2010 at 18:06

As MarkD mentioned, the 5 gallon buckets are the way to go for ready-mix. They seal up nicely and have a very long shelf life. If I pull out an old one, I'll usually add a bit of water, mix it up a bit, and it'll be fine.

Just to cover another option - you also have the dry unmixed compound that comes in bags. These are really an entirely different beast from the pre-mix buckets though:

  1. They tend to absorb moisture from the air, so shelf life is limited to maybe a couple months before they get "clumpy".

  2. They dry much more quickly (20 - 90 minutes depending on the variety), which is nice if you want to put on multiple coats in a day.

  3. They dry much harder - the faster they dry, the harder it will be - which is nice for filling low spots or base coats, but terrible for sanding.

  4. Once they start to dry, it's over - you can't add water to soften them up. So you only mix up as much as you can put on in 15-30 minutes or so. If it starts to set in your mud tray it's too late - throw it out and mix up some more.

  • 3
    For a first time mudding, I'd recommend going with a pre-mixed compound. One has enough to worry about those first (20) times mudding- adding mixing the powder to the right consistency (without even knowing what the right consistency is) seems like a recipe for frustration. (all too much experience with frustration here. ;) )
    – MarkD
    Oct 25, 2010 at 18:06
  • 1
    @MarkD - I'd agree with you 100% there. Just thought I'd add some info on the dry mix options for others who might wonder about this later. Oct 25, 2010 at 18:36
  • Understood. :)
    – MarkD
    Oct 25, 2010 at 18:51

In addition to pressing the plastic sheeting over the surface as @MarkD suggests, make sure you also pack it down flat before doing so. Take the time to scrape all the extra mud off the sides of the box/bucket and smooth out the top surface. This will minimize the area exposed and keep you from getting crusties flaking off the sides of the container into your good mud.


No one understood what he asked which is ridiculous. Store the unused dry mix in a garbage bag and tie it and put it back in box or a container with a lid. Store it in a cool area. It will last forever.

  • No a box of mud is different. It is premixed compound like a bucket of mud but supposedly cheaper and greener since the plastic bucket is not part of the cost and environmental impact considerations. homedepot.com/p/…
    – Kris
    Aug 21, 2020 at 3:32

Best Way....cover the mud with water before replacing the lid. When you need it again, simply pour the water out. It will still be sitting on top of the mud, protecting it from the air above.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.