what is the maximum drywall mud thickness on ceiling?

Question

I am remodelling a home with some new drywall and some older plaster. On a ceiling where the thicknesses dont match up ( in some cases its near 1/2 inch difference) , is there a maximum thickness to which I can build up the mud to even the surface?

Answer 1

1/8 or 1/4 inch...and the reason is...it will crack if too thick when it drys...good luck

Answer 2

Well I read everybodys answers and they are all wrong about the thickness. Ive been doing drywall for 30 years you can use some drywall mud called durabond it comes in 4 different setting levels 20 minute,45 minute,90 minute and 210 minute and this mud comes in a powder form. Ok lets say you are going to use 20 minute mud. From the time you add the powder with water you have 20 minutes to get this mud on the ceiling and get your tools cleaned up and the mud will be as hard as a wedding dick any place you have seam you will have to use drywall tape. Myself I like to use fiber tape when dealing with plaster but in the corners you cannot use fiber tape you will have to use paper drywall tape. Any time you are using durabond always put water in your bucket first then add the powder then mix. If you mix it any other way the mud will be lumpy. When you buy your durabond make sure you buy easysand. If you buy it in the brown bag with green lettering good luck on trying to sand it. I wish I was there to help you out alittle and give a few pointers but I cant I live in northern Michigan. Now if this is not your best answer I will kiss the front bumper of a moving car.

P.S. you wont have to worry about cracks.

Good luck

Oldman

Answer 3

Here is what I would do...
If there is 1/2 or 1/4 inch difference, I would shim the studs by 1/4, or 1/2 or whatever the difference is. Get 1/4 or 1/2" strips of wood and screw them to the studs before putting the drywall on. then use 1/2 (I wouldnt use anything thinner) inch drywall so that it lines up almost perfectly. If you fill the gap with mud or joint compound or whatever, it will take a long time, you will have to apply several coats and then wait for each coat to dry.. etc.

Answer 4

20 Minute Drywall Mud

Answer 5

well, strictly speaking you can build up that much drywall mud, no problem. the problems come later. the thicker it is, the more likely it will crack later. getting a good bond will be key. they have some additives like latex you can use in the dry mud to get better adhesion and resistance to cracking. I have seen guys use lightweight variety of automotive bondo. That's expensive though. I would make sure to use the mesh tape in it, so as to get at least a little resistance to cracking.

Answer 6

1/2" is about as thick as I'd ever want to go.

I don't know what your project consists of exactly, but you might consider puttinga 1/4" sheetrock over the entire ceiling. I did, and it is very nice having a nice, smooth, crack-free ceiling. And really, it's not much more difficult than doing what you're doing now. Just a thought.

Good luck

Answer 7

I think adding some a couple inches of wire lathe on the thin side would be a good idea in addition to tape and you should have a smooth transition. You can use as much mud as you need in thin coats, and the lathe will give added strength.

Answer 8

The overall thickness has no reasonable limit, but it must be applied in 1/8 to 1/4 inch coats.

Answer 9

As thick as you need. Just be sure that you put drywall tape on the seams. Good luck.

Answer 10

add drywall to bring the difference to 1/4". Then add two 1/8" coats.

Answer 11

On the parts that are thicker you need to sand it down to where its 1/8 inch or less. After you sand it out you need to match the thickness to a max of 1/2 inch (preferably 1/4 max is best).