Ledger board for a Cast iron tub?

hj said:

You are NOT supporting the tub by its lip, you are integrating the tub with the wall surface. The only way it would be supporting the tub is IF the legs compressed into the floor, and in that case the lack of a ledger board would create a crack betwen the tile and the tub. AND Kohler tubs USED to REQUIRE a ledge board before they started adding feet to the tubs, and they NEVER cracked.

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Right and by "integrating" the tub with the wall surface, the moment the tub gets compressed into the floor or the floor sags, you then are supporting the tub with the wall. Also, that "Crack" you are talking about is one that should be filled with silicone. Not exactly a hard crack to fix. However, by supporting the tub by the wall, you create all kinds of possible problems - the tub becoming out of level, the tub not being supported by anything but the face and the wall, and on top of that the tub not being warrantied.

I'm no expert, but I've worked with enough "seasoned veterans" to know that the "I've done it for 30 years this way" argument is one to be ignored unless good reasoning is supplied.

I wouldn't have replied at all had the thread not been focused on humiliating a home owner who is trying to install this himself instead of paying someone else. If you don't want to run a website that respects the people you're trying to help, then what is the point?

Regarding the standard Kohler cast tub, like the Villager and the Mendota, I like to use the ledger board.

I've been installing Kohler cast iron tubs since 1974, and the best way to install without problems is with the ledger board on the back wall. Kohler makes the tubs so the feet never even touch the floor. And if they did touch, the area is so small it would press into the flooring and drop down. That's why you would need a metal plate and shim if you weren't using a ledger board. I know that hj, who has been installing tubs for much longer then that, is just trying to save someone some grief. And when tile is grouted in, the tile setter leaves the gap between the tub and wall open, and uses Silicone. If it were to be grouted there, it would crack and fail. There needs to be a pliable connection between the two surfaces. Though with the ledger board approach, there won't be much movement anyway.

Going back years later, I've never seen a problem. Never.

FWIW, my guess is that where HJ practices his trade, the vast majority of homes are built on slabs, so if level, the feet would be solid and not sink in. There are huge areas of the country where the bathrooms are on wooden subfloors, and the combined weight of a CI tub + water + a person or two could allow the tub to sink into a wooden subfloor a bit over time with those relatively small feet on some tubs. So, a ledger board to keep things level over time isn't a bad idea. Tile industry calls for a soft joint (i.e., caulk or some other expansion joint) at all changes of plane or material, so the correct thing between the tub and the tile is one of those. If you want to avoid caulk altogether, there are companies that make things that you can use such as http://www.schluter.com/4_10_dilex_as.aspx . They (and others) make corner expansion joints as well so you can build a caulk-free, water-tight structure. The detailing on how to install this successfully is critical, but not hard. The corners need to be plumb and square, though, and that may take some work to achieve.

Thanks for the tips Terry.

You know I was reading the instructions on a Toto Toilet like 9 years ago and having a hard time with my through holes and mounting jig. My client found some online advice from a plumber in Seattle who has a Plumbing Forum and his advice was to drill a 1/2" hole and not the 5/16" one spec'd.

Ever since I have been a fan of the site.

Advice written from "Pro's" and not "Joe's".

Speaking of which. Nice plug for Schluter Jim - I bet you have never installed one of those before. To think a movement joint will help a tub rocking about the place is silly and the movement needs to be fixed before proceeding.

Their is also a Spanish company called Butech that produces a wonderful line of tile transitions but I would suggest none of those for a wobbly tub.

No $17.00 Schluter strip will correct the moving tub.

Sorry Jim.

Grani Rapid is a modified thin-set with build in movement. Custom Building products also make a similar product. Neither can be installed over Kerdi and neither is acceptable for a tub that moves.

Follow the advice here from the plumbers. Get the tub solid. Then waterproof your walls and you have a proper install. Out in the field things are tuff. Sometimes tasks needed to repeated over and over to get proper results.

It's called work. Hard work.

As in life - building a bathroom does not always go easy. Follow the proper steps. Listen to the advice from those in the business and perhaps your job will be built a little more soundly.

JW

Misreading things again...where did I say a movement joint would stop the tub moving? I said use it instead of caulk and that a ledger board is not a bad idea. Get a life John...

Using an engineered movement joint that keeps you from digging out old caulk for the life of the fixture and continues to look good is a reasonable thing...caulk doesn't last forever and can be a pain to clean out and re-do. A good engineered soft joint should last the life of the remodel, or until you're tired of it. It can be removed and caulked, if it ever does get to looking bad, too.

I decided to not use a ledger and just shim the feet. I saw that someone used 4x4 junction box covers as shims because you don't need to be as exacting, so that's what I used.

Note: My floor is flat, eliminating some headaches. Also, we had access to slide the tub in through a side wall and just push it straight back once we cleared the toilet shutoff.

Here's the approach my nephew and I took:
(1) Marked out 4x4 locations for the feet on the floor with tape, centering the feet in those locations.
(2) Firmly duct-taped one shim in each location as a base to spread out the load under each foot.
(3) With the tub on its apron on a dropcloth, we lowered it down onto its feet and with the toilet shutoff between the basin and the apron. This put the tub within about a foot of the rear wall.
(4) Checked for level then duct-taped additional shims on top of the base shims for the rear feet as needed.
(5) Lifted the apron onto a 4-wheel furniture dolly then we braced ourselves with one hand on the rear wall. Lifted the tub with the other hand by grasping the rear ledge then pushed against the apron with our knees to get the tub to the back wall. We had to push it about an additional inch or so after setting the apron on the floor.
(6) Checked for level then lifted the apron onto a couple 2x's by grasping between the studs on the side walls; the front feet could then be shimmed. The dolly may be required again to get the tub up onto the shims after shimming the front feet.

I hope this helps.