Replies

1. 
   JTC1 | Oct 14, 2007 10:49pm | #1

   Details ? Sounds like it is a little late as you say you "installed" the tub.

   Underlayment for what? Tile? Vinyl? Other?

   Jim

   Never underestimate the value of a sharp pencil or good light.

   
   

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   Edited 10/14/2007 3:51 pm ET by JTC1

1. 
   user-54984 | Oct 15, 2007 03:15am | #3

   In this case it was tile so I put the tub in and then let the tile guy go up to the tub with his underlayment. As I was doing that I was thinking about vinyl and how the best way to do that was. I have always put the tub in first but I was wondering if there were any pros or cons about doing it the other way.

1. 
   JTC1 | Oct 15, 2007 04:19am | #5

   Depends.

   In many of the homes I work in here in DE, circa 1950, the original subfloor is only 1/2" plywood.

   The subfloor was topped by 3/4" hardwood in the main part of the house or a second layer of 1/2" plywood covered by WtoW carpet.

   Bathrooms were frequently 1/2" plywood subfloor, a 1" mud bed with wire mesh and then tile.

   When I tear out a mud bed in one of these and intend to install vinyl, I frequently will run 5/8" or 3/4" plywood over the entire floor to better maintain the elevation in relationship to the adjacent hallway.  The additional plywood also helps to stiffen the floor back to something more similar to the feel the floor had with the mud bed and tile installed.

   I frequently find water damage to the subfloor, particularly in the tub area - right where the new tub edge will be sitting.

   The additional plywood helps to reinforce the tub edge area (which I may have patched).

   I usually PL the additional plywood to the old subfloor and then nail.  In essence, I am not installing underlayment - I am reinforcing the subfloor.

   The true underlayment (which will be covered by vinyl) runs to the tub edge for future tear-out considerations - no PL but I do use rosin paper and lots of annular ring nails.

   Same with tile installations except, I am now looking for a combined wood floor thickness of 1-1/8" or better - there is usually lots of space after a mud bed tear out. Then Ditra, 1/4" Hardie or 1/2" Hardie to control the finished tile floor elevation.

   When using any of the cement boards, or Hardie, I run #30 felt over the entire floor including under the tub. Then the cement board gets thinsetted and screwed to the exposed floor - the thinset serves to fill any voids between the cement board and floor - felt serves as a moisture barrier and a "slip sheet" for the cement board/tile floor - sort of a release layer - same principle as Ditra.  

   Jim

   Never underestimate the value of a sharp pencil or good light.

    

2. 
   NickNukeEm | Oct 14, 2007 11:36pm | #2

   When remodeling a bathroom, I set the tub on the subfloor (plywood on the joists). Any additional underlayments for finished flooring are laid abutting the tub.  This puts the finished floor directly up against the tub, and makes it easier for the next poor schlub that has to remove it for another floor install.

    

   "I am the master of my fate, I am the captain of my soul."  Invictus, by Henley.

1. 
   user-54984 | Oct 15, 2007 03:17am | #4

   Good point about tearing it out later. I've had to cut the underlayment many times when they ran it under the cabinets.