Mud Work Hints and Methods

[Davy]

With a two day old scratch coat, the brown (finish) coat will set faster for you. Nothing wrong with doing it that way. I assume your friend is doing a one coat mud job using sheetrock instead of a scratch coat. I've done it that way hundreds of times but I like to put up felt paper over the sheetrock or greenboard.

I will say this, recently I tore out a shower we tiled 20 years ago. It was lath and mud right to the green board with no moisture barrier. Of course back then we thought the green board was our moisture barrier. I was surprised to see no water damage at all to the green board. Not even a stain in the green paper. No moisture had even gotten thru the mud bed, not even down low on the walls.

[T_Hulse]

I was surprised to see no water damage at all to the green board. Not even a stain in the green paper. No moisture had even gotten thru the mud bed, not even down low on the walls.

Cool.

[John Bridge]

When I first learned the one-coat (in the West) we put the mud over anything that was there, including regular sheetrock. We figured the tile, grout and mud would be waterproofing enough.

I have figured otherwise since then.

[Lunastileandstone]

cx I tried searching for same day and couldn't find anything on it

Hamilton yeah ive been doing it that way for years and never had a problem. his argument was that fat mud shrinks and it would cause tiles to crack

[cx]

Did you put that query in quotes, Ricardo? I find 26 posts with that phrase.

[Lunastileandstone]

it worked thanks cx

[BigGibby]

Hello guys. Have any of you used Custom Building Products un-sanded unmodified thin-set as a bond coat to a mortar bed with the dusting by hand standard procedure method? Or, what have you used,or, are using now? Thanks a bunch, Tommy.

[Davy]

I use Versabond and I don't dust it, I mix it and spread it and quickly get it covered with mud. It can be mixed a little thinner than usual for this.

[Higher Standard Tile]

I usually use Laticrete 253 or 254 as a slurry for bonded mud beds. Like Davy I mix a little looser than I would for setting tile.

After cleaning the slab I burn it in the flat side of the trowel then spread it with a V Notch or worn out 1/4" x 1/4".

[Hamilton]

That's a manly box edge there Davy. What is that...8-10 ft?

[Davy]

Hi Jack. I believe it's the 8 footer. I do have a 10 and 12 but I mainly use them to run mud screeds in large areas.

[Jim Cordes]

@Tommy, Sure you can use an unmodified if you want since you would be on concrete. but I believe modified would be the better bet..better bond and perhaps a bit of flex.

I use the bond coat as an opportunity to use up old and leftover mortars since just about anything make a decent bond coat. But if I do have to buy something for a bond coat I will spend the extra money to get modified...a basic modified that is.

[Jim Cordes]

@Davy, im curious in the pic im guessing you didn't use any sill-seal or any type of expansion material against the brick house. Im not a bean-counter but what are your thoughts on that. Up north here i think it might be slightly more important but really i don't see the mud expanding..it anything it will just have a cold joint and a small shrinkage crack.
hence the only reason to have the expansion material is basically to support the caulking(backer rod basically).and if the crack is small enough then the caulking will support itself.

I would probably use the sill-seal and some good urethane caulking. but im kinda feel the expansion material is kinda a waste of time for a job like the above pic..thoughts?

[BigGibby]

Hey guys, thanks for the timely response. Actually what I'm asking is , has anyone done what I outlined there? And yes, I have used just about every method out there and plenty of custom applications.. you know what I mean.
After so many years and scratching of head, you get that way. Anyway I'm sure guys are dusting beds and setting directly into it. The specs on Sure Bond un-sanded thin-set say it is very water retentive, gotta be something like the old "L&M". Fact is I relocated from Jersey metro NYC area to East Kentucky and every time I ask a question no one knows what I'm talking about. I'll be back, thanks, Tommy.

[Lou_MA]

This can be split off into a separate project thread if needed, but I had a few generic questions.

I haven't yet gone through this entire thread, so if there's a link to basic mud FAQ's or anything, just let me know.

1. If Kerdi or Hydroban is being used over a two-coat method, is there still a moisture barrier over the studs? Wouldn't that lead to a moisture sandwich?
   
   
2. When hanging the lath, do the horizontal overlaps in between studs have to be fastened together with wire ties or anything?
   
   
3. Do the vertical overlaps in the lath need to be over a stud? Or can they be in the middle of a stud bay? If so, do they need to be tied together with wire ties?
   
   
4. How deep are the "scratches" in the scratch coat?
   
   
5. Is the scratch coat meant to be a consistent thickness? Or can you start to build out where needed?