Tub to shower base conversion


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Old 09-03-15, 02:47 PM
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Tub to shower base conversion

Hi all,
I am remodeling my bathroom, mainly with the purpose of replacing the tub with a shower base to make it mom friendly, as she has a tough time raising her feet high to step into the tub.

I removed the tub, it was a 60x30.
I am replacing it with a 60x32 shower base.

The flooring meets the old bathtub and the floor has a 1 inch backer board on it.
So, either I need to remove a 60x2 strip of the backer board, or I need to shim up the rest of the shower floor by an inch.

What would be the prefered way to solve this problem?

Thanks!
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  #2  
Old 09-03-15, 03:24 PM
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Welcome to the forums! The first thing you need to do is relocate your drain to accommodate the new base, and make it 2" pipe from the drain to where it ties into the larger drain lines. I know you didn't want that cropping up, but it is here and won't go away. As far as the width, cut the old and demo it out to the dimension you need.
 
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Old 09-03-15, 04:44 PM
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Thanks! Especially for the drain pipe pointer. I probably would have learnt it much later if you hadn't mentioned it.

"cut the old and demo it out to the dimension you need".
This cement board is 1 inch thick. I could use a circular saw, but being indoors, is there a good "dust free" method?
 
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Old 09-03-15, 08:20 PM
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Hi Tbone,

First of all, that base in not cement board, it's a mud job mixed and floated on the job. From subfloor up you've got; tarpaper - metal lath - deck mud - then the thinset and tiles.

Circular saw will not be good. You need a angle-grinder with a diamond blade for dry cutting. Lots of dust, need a helper with a shop vac. Plastic the doors and maybe a fan if you've got a window. Harbor Freight has cheapo for under $20 + blade.

Jaz
 
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Old 09-04-15, 03:27 AM
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Jaz may be right, but it looks like Gypcrete to me. In either instance you will need a grinder to cut it back and it will be messy.
 
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Old 09-04-15, 04:46 AM
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OK, I will work on removing a strip along the edge today.
I only need to remove a 2 inch strip (2 1/4, in case the new shower base needs some wiggle to get in)
I was wondering if I could chisel it away. Mainly, I need to ensure that the mortar on the rest of the floor stays in good shape and I will tile over that. As you can see, mortar is cracked in the corners. That is from my hammering at it. The tiles were stubborn there and came off in layers.
 
  #7  
Old 09-04-15, 06:07 AM
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I'm curious as to why consensus seems to be to remove the strip instead of adding a couple layers of backer board to build up the tub area. For one thing, I'd want to look at the shower base and make sure recessing it an inch won't cause the finish floor to hit shower base at a bad location. Also seems like adding the backer board would stiffen the floor, always a good thing. It does mean losing an inch of headroom, but can't imagine that would be a deal breaker. Am I missing something?
 
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Old 09-04-15, 07:03 AM
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You raise a good point, CarbideTipped.

I checked the shower base and it's curb side is smooth and flat the entire length. So, as long as I cut the strip out straight, the issue that you raise shouldn't be there.

OTOH, it will be a lot less laborious to build up the shower floor that messing with the mortar.

I would like to know if either option is equally acceptable as the other.
 
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Old 09-04-15, 07:46 AM
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Either option is fine. Building up the floor with cbu won't give it strength, but will provide the lift you may desire once you decide on your final flooring.
 
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Old 09-04-15, 07:54 AM
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That's great to hear!

The flooring plan is to remove the existing tiles, scrape out the thinset and lay new tiles.
So, the final height is defined by the existing mud layer.

Can I use plywood to build up the shower area (as opposed to mud)?
 
  #11  
Old 09-04-15, 08:04 AM
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I'd use two layers of 1/2 inch concrete backer board (like Hardiebacker) adhered to subfloor (and between layers) with thinset mortar. You spread the thinset, lay the 1st layer and screw it down with backer board screws, spread the thinset and lay the second layer and screw it down. The thinset also gives you a little wiggle room to make sure it is level and even with existing floor.

Cutting the CBU can be messy, but at least you can do it outside or in garage.

Make sure you do the drain work first so you can cut the backer around the drain.

I'm not sure this is really less work than cutting out the strip, but it's an option. It will certainly cost more although CBU and thinset are not expensive.
 
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Old 09-04-15, 08:36 AM
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At this time, I am waiting on the plumber to come in convert the drain line from 1 1/2 to 2 inches.
Since the linehas to be changed all the way to where it meets the bigger line, I'll let a professional handle it.

In the meantime, thinking out loud here:
-There is an advantage to cutting out a 2 inch strip. The shower base has a 6 inch curb. It will become 5 inches with this option, helping my mom out a bit more. Every inch counts when you have arthritis.

-In case of building up, why do you prefer cbu? The old tub was sitting on plywood. Just curious.
 
  #13  
Old 09-04-15, 09:15 AM
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How about give us a link to your specific shower base and we can advise better on which way is better. Some bases need to be set in a bed of cement, others don't. Some can be supported along the tile flange, others can't. Tough to advise specifics without knowing what we are dealing with. Personally, I would have had the 2" cut out by now using a shop vac and a roto-zip with diamond blade.
 
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Old 09-04-15, 09:26 AM
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czizzi, agree wholeheartedly.
I am using my vacation time to do this and waiting for the plumber for a few hours and not doing anything in the meantime seems like a waste!

Here is the link to the shower base I will be installing.
Shower base

Installation instructions
 
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Old 09-04-15, 09:31 AM
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Chandler, I'm pretty sure it's not Gypcrete, they wouldn't go through all the trouble of mixing Gyp in a residential home. You're looking at the thinset over the deck mud.

I agree that either cutting out a strip or raising the floor under the shower would be just fine. (I vote for removing the 2" strip), However, I disagree that installing CBU would be best. CBU adds virtually no structural strength. Use ply or OSB if you decide on this route.

Tbone, no reason to try to remove the thinset. Just knock down any high spots. What size tiles will you be installing?

Jaz
 
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Old 09-04-15, 09:55 AM
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Jaz,
I'll be using 13 in x 13 in tiles.

So, if I only knock off the high spots on the old thinset, there will be some minor non-level surfaces remaining. Won't the trowel track these as I use the notched side? Glad to hear I don't have to go crazy with the removal.

I was thinking of renting a hand-held floor stripper.
 
  #17  
Old 09-04-15, 11:25 AM
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Your base get set in a bed of mud. Cut out the strip - does not have to be perfect as you can bridge any imperfections with your tile and none will be the wiser.

Some people have great luck with a stiff putty knife and a hammer - use it as a chisel to pop the tile off the mud bed. I do it all the time, but I have a demo hammer with a tile bit on it.
 
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Old 09-04-15, 01:21 PM
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Got it. Thanks! I picked up some cold chisels, an angle grinder and a diamond blade.
I'll use the angle grinder only as a last resort, but picked it up anyway because I'll need it later for cutting the tiles around the toilet and such.

Will update the forum when it's done.
 
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Old 09-05-15, 08:02 PM
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Hi all,
I have chiselled out the necessary width from the mud base.
I am down to the metal lath, and I don't think I have anything in my arsenal to cut the lath out.

I was thinking of a tin snip. I can borrow that from my neighbor first thing tomorrow.
Is that good or do you suggest another method?

I have a plumbing related question and I shall open another thread for that.
 
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Old 09-06-15, 05:00 AM
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Snips are fine, you can also bend and snap it. Depending on the orientation, you can also rip it along the smaller metal slats interior to the lath. Wear leather gloves to protect your hands. Fold/roll it back on itself to dispose of
 
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Old 09-06-15, 05:41 AM
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Thank you, czizzi.

I just realized I will run into another problem.
If you look at the image in my original post, the hot and cold water lines come up in front of the sole plate. That maybe OK for a tub, but I don't think it will work with a shower base.

I will try a dry fit today and stop short of touching the pipes with the base. Looks like they will need to be re-routed through the sole plate, which is probably something I should do anyway.
 
  #22  
Old 09-06-15, 10:27 AM
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the hot and cold water lines come up in front of the sole plate
Why did they do that? hugh...... On the plus side, you will get lots of practice using your solder and torch. Unless that is something that the plumber was also going to tackle. Which will give you lots to think about while you wait 2 weeks for him to show.
 
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Old 09-07-15, 06:32 AM
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It's a bummer. My neighbor who is an expert in sweating pipes suggested the Sharkbite solution. He is confident of their quality and has been using it in his home as well as his parents.

I realize it is a contentious issue in the forums and opinion on them is split. However, going strictly by facts and numbers, I am comfortable with using Sharkbite. Building code allows them to be used behind walls.
 
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Old 09-07-15, 07:33 AM
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I've seen them leak, so they are not infallible. Just make sure you give them a good amount of time, under pressure, to ensure a good seal. I would do the supply work now, and give it a couple of weeks to sit under full pressure until the plumber gets to the rest of the drain. The only thing that will not show, is it if under hammer pressure when the water if turned on and off if that makes a difference.
 

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Old 09-07-15, 09:47 AM
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Czizzi,
I am sorry, I don't undertand your last statement: "The only thing that will not show ...".
Could you explain?
Thanks!
 
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Old 09-07-15, 09:54 AM
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Research water hammer arresters

Water lines are under pressure. When you turn on a faucet, you release the pressure. When you close the faucet, you allow pressure to build back up. Some houses are subject to the pressure banging the pipes when the faucets are closed. Water hammer arresters are installed to ease the pressure to prevent the banging. We recently had a thread that the poster was complaining that when he turned the water off to the bathroom sink, it would cause a small squirt of water to be released at the toilet. It is that quick pressure bump that can not really be tested on a sharkbite and if it maintains a seal once hidden in the wall.
 
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Old 09-07-15, 12:02 PM
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Great explanation!

It seems to me that the hammer effect is most pronounced at objects that are in the cross-section of the pipe (cylinder), such that they meet the force of the water head-on. Things like faucets, shut off valves, caps etc. The objects that run along the walls of the pipe, such as coupling, slip joints etc may not experience a lot of the impact as it might be spread along the length of the cylinder.

However, like you said, I will have several days where the sharkbites will be under pressure. I will also open/close sink faucets there frequently during this waiting period.
 
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Old 09-07-15, 02:47 PM
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Make sure you bleed all the air out of the system in that area so that the sharkbites are actually under pressure from water and the air in the system is not acting like a hammer arrester. If on the cheap, use an 1/2" iron pipe with a cap to cap the drop elbow for the shower head (paste and tape the threads). You can unscrew it enough to purge all the air from the rough in. Or a plumbing supply house will have plug specifically designed for this application.
 
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Old 09-07-15, 08:44 PM
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Made a lot of progress today...fitting for labor day!
  1. Cut the metal lath out with a multi-tool & a metal cutter.
  2. Used sharkbites to reroute pressure lines through base plate.
    • After 2 hours under high pressure, no leaks
    • When sink faucet is turned on and off, one of the lines vibrates momentarily. Vibration is quite pronounced. Hammer effect?
    • Vibration can be minimized by securing lines tightly to 2x4 pieces across joists
  3. Dry fit the shower base
    • Sub floor was level to begin with.
    • Shower base was level on all sides and across.
    • Marked the drain location.
Please let me know if I missed anything so far.
 
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Old 09-07-15, 11:02 PM
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Could you take a looks at steps 4,5,6 in the installation instructions of the shower pan I am using?

The subfloor is level in all directions. A dry fit was successful, with everything level. So, do I need to plop leveling compounds on the subfloor as these instructions seem to suggest ?
 
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Old 09-08-15, 08:21 AM
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The level compound is designed to support the feet evenly. Even though the base feel sturdy, over time and also with humidity changes, you may get some bounce. The compound is to help spread out the feet so that there is also a bigger pad with which the feet to set on. I would not skip this step.
 
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Old 09-08-15, 12:37 PM
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I am a little confused by these steps. Will the pan self-level by itself?

Assuming that I place 2 inch mounds on the spots where the feet of the pan will end up and cover it with poly sheet - what will happen when the pan is placed on these mounds?

Will they get squished by the weight of the pan?
How do I adjust level if the pan is not level? I can only press down where needed, correct? I cannot raise any location because the compound underneath is already squished.
Also, won't the level keep changing until the compound cures?

A thickness for the polyethylene sheet is not given. Can you recommend one?
 
  #33  
Old 09-08-15, 03:17 PM
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Leveling compound set up relatively quickly when spread real thin. If you dollop them with a big blob, they take longer to set up. If you say everything if level to begin with then squishing them all the way down should do the trick. I would do a larger than 2" pile.

Big orange has a product in the tile isle called level quick that should handle your needs. 6 mil poly will do just fine.
 
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Old 09-09-15, 10:12 PM
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I was hoping to finish installing the pan today, but got delayed with the drain body mechanism.

From researching the drain installation, I expected a gasket will go around the drain pipe, then a ring will be screwed down using an included tool, compressing the gasket to make a tight seal.

However, I got the Kohler drain (K-9132). This has a Fernco gasket that does not need to be pushed down with a ring to compress. Apparently, you just push it down until it is flush with the top of the drain pipe and that's it. Why wouldn't the Fernco gasket move up over time ?

So, I did another dry fit to measure where to cut the drain pipe. I guess it's top should be somewhere in the middle of the drain body. But, when installing the base for real, won't the squished layer of levelling compound add some height to the base making the top of the drain pipe drop? Not a big deal, because, there is quite a bit of play in the drain pipe because after a few feet after the p-trap, it is hanging free.
 
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Old 09-10-15, 09:20 PM
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Finally, I managed to place the pan according to the instructions, leveling compound and all. But, now, I am having a hard time getting the pan to be level.

I have repeated steps 4,5,6 in the http://www.us.kohler.com/webassets/k.../1161835_2.pdf a few times now.

Sides AB and CD are level. But AC and BD are both slanted downwards away from the curb(CD). So, this means that AB needs to be raised, by about 3/4 inch! What is strange is that the leveling compound under A is completely flattened whereas the other 3 are only lightly squished.

Adding more leveling compound under A and B does not make a difference.
I am thinking of shimming the feet under A and B tomorrow.

Can you guys tell me what I am doing wrong?

Thanks!
Tbone

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  #36  
Old 09-11-15, 03:48 AM
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A dry fit was successful, with everything level
Something is up for it to be fine as a dry fit and then out of wack with a couple of dollops of compound under the feet. Sometimes the compound sets up really fast, is that what is up? Or is the compound still pliable when you pulled the unit. Could also be that the whole unit is sitting cockeyed in the alcove and is therefore torqued in some way. Try setting it on a couple o 2x4 boards so that it hovers above the compound. Then work it into the alcove perfectly square. Then remove the 2x4's and lower into the compound. Don't be afraid to walk on it to settle it down. The resistance to the compound may be too large to just use your upper body weight to settle.
 
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Old 09-11-15, 07:49 AM
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OK, I will try that. It's a snug fit and a 2 person job, so I need to wait till later in the day for some help.

When I pulled it out, the compound was still pliable. I think the polyethylene sheet slows down it's curation.

Indeed something seems to be wrong because one foot is firmly planted and the others are not, as though one side is stuck against a stud. I did walk on it to push it down. Hoping to get this done today!
 
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Old 09-12-15, 10:10 PM
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We finally figured out what was happening.
The curb wall bottom was about an inch lower than the 4 feet!
Adding an inch of shim to the feet took care of this issue.

In retrospect, I should have examined the underside of the base carefully before proceeding to do all the work...it was a 'duh' moment. Obviously, I made a mistake during the dry fit as well which gave incorrect level readings.

It is strange that it comes out of the factory this way. Everyone who gets this pan has to raise the base atleast by an inch, unless it is being installled on a raised bed that allows the curb wall to hang over. At a minimum, this should be mentioned in the installation instructions.

It's all laid out now, nice and level. The drain is connected. The drain fernco gasket was quite difficult to get over the 2 inch pipe. So, I don't think it's going to come off or leak. I have plugged the drain pipe and poured a couple of buckets of water into the base. Seems to be holding up. I will let it sit overnight.


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Old 09-13-15, 03:42 AM
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The curb wall bottom was about an inch lower than the 4 feet!
Adding an inch of shim to the feet took care of this issue.
This is where the level compound comes into play. If you recall, I said previously.

I would do a larger than 2" pile
A larger pile would have allowed you to settle everything into a wider foot pad. Now you sit on shims instead which may not be a stable.
 
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Old 09-13-15, 06:19 AM
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czizzi,
I have used a very large amount of the leveling compound. However, I don't think that is the issue. It will get squished right out by the weight of the pan. (BTW, after 24 hours, the leveling compound was still pliable under the pan. So, it can take a few days to cure.)

Without shims, the pan will rest on one side entirely on the curb wall, which I don't think can take the weight over a prolonged period of time. Since that is one inch lower than the rest of the pan's bottom, the pan will be tilted. Please see attached image.

I don't see how this can be resolved without shims without cutting out a 1 inch strip off the curb wall bottom.

I agree that use of shims is not a good idea. For what it's worth, it's glued to each other and to the pan feet with construction glue. The squished out compound forms a "dam" around the feet. When it hardens, it will prevent the feet from moving on the horizontal plane. I wonder if that is the real purpose of the leveling compound.


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