Cast Iron Tub Floor Height

[Thomas K]

Hi! I am about to install 60" Kohler Bellwether tub. Subfloor now is 3/4" plywood over 2 x 10" joists, with blocking installed under where the tub legs will be. I am installing 1/2" Durock over this subfloor in bathroom, followed by floor tile. This will make floor even with floor in hallway.

Should I install a layer of 1/2" plywood under the tub to make floor even with Durock? Or should I just install tub on plywood, losing 1/2" of skirt height, and Durock up to the tub?

And should I use a ledger board with cast iron tub, or am I opening up a hot debate as I've heard it both ways?

Thanks for any replies!

-Thomas

 

[Terry]

It's less of a step downward exiting the tub if it's set on the plywood.
If you don't support the back edge of the tub then at least use the metal shims to prevent the legs from disappearing into the plywood and watching the back of the tub sink after tiling.
Or you can support the back of the tub like the plumbers have been doing for decades. It's not a new thing you know.

By the way, with a three wall enclosure, how are the shims placed later. That only works with open walls during new construction, and how would the tub be lifted slightly to place the shims? It's at least 300 pounds. Sounds good on paper though sitting behind a desk.

 

[Sponsor]

 

[Thomas K]

It's less of a step downward exiting the tub if it's set on the plywood.
If you don't support the back edge of the tub then at least use the metal shims to prevent the legs from disappearing into the plywood and watching the back of the tub sink after tiling.
Or you can support the back of the tub like the plumbers have been doing for decades. It's not a new thing you know.

By the way, with a three wall enclosure, how are the shims placed later. That only works with open walls during new construction, and how would the tub be lifted slightly to place the shims? It's at least 300 pounds. Sounds good on paper though sitting behind a desk.

Thanks for the reply, Terry! It is remodeling construction; bathroom is gutted, and tub is being relocated to wall closest to door. I was going to set tub, level it with metal outlet box covers (flat shims) and then build a new wall behind it for stacked washer/dryer. Without new wall, tub accessible from front and rear. I will take your advice and set the tub on subfloor, and then Durock up to it (almost up to it; small gap) and caulk.

I believe you if you say I need a ledger board. Call me ignorant, but does board need to be installed after leveling tub with shims?

 

[Terry]

We put the ledger board in first, and then drop the tub down on it.

https://terrylove.com/forums/index.php?threads/installing-a-kohler-villager-cast-iron-tub.33212/

On a remodel, the first thing you check for is floor level.
I measure out where the apron will hit, normally 30" from the back wall on a Villager and using a level find out which end is high. I then take the level and measure back for the back wall ledger board. Doing this means if there is a low end, that will need shimming.
Out of level somewhere requires something to prevent the wicked rocking. I often have to shim the front apron on an older remodel.

 

[Thomas K]

It's less of a step downward exiting the tub if it's set on the plywood.
If you don't support the back edge of the tub then at least use the metal shims to prevent the legs from disappearing into the plywood and watching the back of the tub sink after tiling.
Or you can support the back of the tub like the plumbers have been doing for decades. It's not a new thing you know.

By the way, with a three wall enclosure, how are the shims placed later. That only works with open walls during new construction, and how would the tub be lifted slightly to place the shims? It's at least 300 pounds. Sounds good on paper though sitting behind a desk.

Terry: How do you know exactly where to put the ledger board?

 

[Tuttles Revenge]

I set the tub in and see if its setting level or out of level. Once i get it setting level I scribe a line on the studs. Measure down from that scribed line the thickness of the edge of the tub is where your ledger goes.

The biggest reason you want your tub level is that the tile installer is going to install their material level and plumb. If the tub isn't level the gap between the tile and the tub grows and you see it and it looks terrible.

 

[Thomas K]

I set the tub in and see if its setting level or out of level. Once i get it setting level I scribe a line on the studs. Measure down from that scribed line the thickness of the edge of the tub is where your ledger goes.

The biggest reason you want your tub level is that the tile installer is going to install their material level and plumb. If the tub isn't level the gap between the tile and the tub grows and you see it and it looks terrible.

Thanks! I wondered. Now I know.