# Bathroom built on a mudbox



## soparklion11 (Feb 24, 2017)

I own a house circa ~1940. The toilet flange was fractured and the tile also cracked in that bathroom, so I removed the tile to find that the tile was laid over old tile that had been laid over concrete.  The joists had been 'trimmed' to allow for the mudbox.  There are two cracks that run with the joists and extend through the old tile.

I plan to re-mud to have an appropriate level surface.  How can I build up an undersurface that I can use for a tile bed that I could later change to another tile without replacing the mud box?

Should I just layer: Mudbox - ReGuard - Tile

OR layer: Mudbox (low) - Backerboard - Tile

If I was to place a layer of backerboard, how would I secure it to the mudbox so that I could remove the backerboard without damaging the mudbox?  Liquid Nails?

Thank you.
Brian


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## Snoonyb (Feb 24, 2017)

In stall the closet flange so the top is even with the eventual level of the finish floor. If the closet bend is to short to accommodate this, you'll need to set the flange below the eventual level of the finished floor and then use closet flange extenders.

The "mud box" as you refer to it, is actually a method used to install the floor sheating between the floor joists, instead of on top of the floor joists, creating the additional depth of the tile mortar bed.

So, after you have the closet flange worked out cut a piece of 3/4" plywood to fit between the floor joists and around the closet bend, fasten some expanded metal lath over the area to be mortared and place the mortar to your desired level.


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## slownsteady (Feb 25, 2017)

SPL; are you planning to replace the entire floor?


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## soparklion11 (Feb 25, 2017)

Yes, I plan to replace the entire floor.

I will also be sure to use metal lathe - thank you!


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## Snoonyb (Feb 25, 2017)

You have a couple of options; 1. as stated. 2. remove all of the existing "period" mosaic, mortar and 1x blocking. Then place 5/8" floor sheating, wonder board and tile atop. 3. metal lath over the 5/8, mortar bed for tile.

The determination rests in the transition at the door, flush, step-up, stepladder.


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