Curbless shower

[Kirk Grodske]

My inlaws had an old tiled shower that leaked at the curb and sidewall joint which started the rotting of the sub floor. They then had vinyl over underlayment brought up to the face of the tiled curb and either not sealed or the seal failed and that lead to more dry rot of of the 2x6 diagonal sub floor.

I have removed the underlayment and vinyl and found a few termites next to the toilet flange that was also leaking and buckling the underlayment. Other than that the subfloor is sound. The drain and pan of the shower was not leaking, but I am replaceing all that since I need to lower the shower so I can have a no-curb design. My father in law needs to use a walker or chair to get around now.

It is a 3 foot x 3 1/2 foot shower with an opening on the diagonal of one of the corners. I intend to tile the entire bathroom floor and bring the water proofing layer of the pan out 2-3 feet. A ceiling mounted curtain will contain the spray. I am taking out all the tile and plaster of the old shower and will drywall the ceiling and 10 inches of the walls. then use backer board or mud job to form the walls. I will do a sloped mud sill pan with CPVC liner or Chloraloy if I can find it. 4x4 tile with 1/8 inch grout lines unless you think it is better for cleaning to but them together.

My question is do I put a layer of plywood down and then a mud base or CBB or just the CBB? I already have the 1 1/2 inch thick diagonal subfloor. Or do I remove all the sub floor and start over with Plywood and whatever else?

Should I just make a gentle rise to the middle of the bathroom to make the slope back to the drain or slope the entire floor? The Bathroom is 90 inches by 55 inches with the door and the shower at opposite diagonal corners, so it is a small room.

I will be removing all the damaged subfloor and repairing or replacing any framing members that are damaged.

Thanks for all the help.

KirkG

[Davestone]

Kirk, i believe the general feeling for these elevated handicapped showers is to somehow recess the shower area itself. This would involve cutting out the 2x6s and using plywood there. Then of course you may have to tear it out on the remaining floor too, depending on your joist structure. Can you give us your joist specs to run through the deflecto above on this page? Then bbcamp or one of the remodeling genies can give you specifics, on the subfloor requirements.

[Kirk Grodske]

Thanks Dave,

Floor joists are 16 on center going across the short dimension of the room. I believe they are 2x8 joists, since they are visually narrower than the diagonal subfloor which is 2x6 for sure. I forgot to take that measurements when I was under the house, so I am guessing. I just looked at some pictures that I took, they may even be 2x10.

I won't be able to check that until Monday now.

Kirk

[Davestone]

Click on deflecto above Kirk, and it'll give you the needed specs to evaluate your floor.In order to make sure the job is a success, it's crucial to know how strong the the structure is.

[Kirk Grodske]

Right. But it will have to wait until Monday for the Deflecto portion. The other questions regarding where to put the slope can be undertaken while we wait.

Kirk

In my (very) limited experience, carpenter ants are usually the culprits in wood that is kept wet by leaking plumbing. The important thing is being sure that you get rid of them; carpenter ants are somewhat more difficult to eradicate as termites must constantly return to the ground via tunnels whereas carpenter ants can live in your structure indefinitely. Most termites are white, while carpenter ants look just like (and are) the big black ants we have all seen.

[John Bridge]

Hi Kirk,

Got a minute here before I start baking the ham.

I would waterproof the entire bathroom floor. And as Dave said, cut down the joists in the shower area and double them up if necessary. It would be logical then to use the Kerdi shower method from Schluter Systems. Use Ditra for the bath floor. The two can be connected in such a way that there is no possibility of future leaking.

http://www.schluter.com

[Kirk Grodske]

Hi John,

Good to hear from you. Enjoy the ham and all the holidays. We have had a good mix of foods here and I am still stuffed.

I will review the material on Ditra and Schutra. I have never used any of them before. What is the reason for using both rather than one over everything?

As far as termites and carpenter ants, these are definately subterrainian termites. I saw and captured live bugs to show the termite guy that came to the house. The homeowner has an annual contract with them.

Subterrainian termites can't live in your house without a souce of water. That is why they normally return to the soil each day and travel in the mud tubes.

I am planning on using the Simpson 1/4 inch lag Strong Drive screws to sister on the joists in the necessary places. I will make the final decision on Monday night after I go and measure the actual joist size and spans.

Any advice on the type of drains and or toilet flanges to use? Would you also run the water proofing over the toilet flange area as well? I would wonder if that would allow "dirty water" in the case of a leak, to get between the layers.

Happy Holidays to all.

Kirk

[jadnashua]

Ditra is an anti-fracture membrane - helps isolate movement between the tile layer and the underlayment. Kerdi is a waterproofing membrane. Ditra happens to be waterproof if you seal the seams. Kerdi is thin enough so that by overlapping the seams, it produces a waterproof system. Either can use either strips of Kerdi, or Kerdi-band (thinner) to seal butted up sheets. Sort of goes on like wallpaper.

[Kirk Grodske]

Thanks for the info Jim.

I have always been reluctant to "mix media" in the past as to the compatability of the various systems. I will look into them and see what I can learn.

thanks again

Kirk

[jadnashua]

Schluter makes some neat products. I used some of them in my recent (not quite finished!) remodel. I've been looking at the discussions on the Wedi board stuff. It also seems like it has some interesting products. Wedi has some systems specifically designed for curbless showers - one the them is reported to be ready to tile a couple of hours after start of assembly. Some of the products are modular, and go together very quickly. There are some links on one of the discussion threads here. Not sure how easy they are to get here, but apparantly, they're in the country. Looks like it may be ideal for me to put in my mother's house. Need to read a little more and check actual dimentions and available space first.

[Kirk Grodske]

OK! the facts are in. 2x8's floor joists spanning 11 feet 3 inches from stem wall to stem wall. 2x6 diagonal sheathing currently in place.

What to do? Add layers to 2x6 sub? Remove and start over? I have to remove some to correct the rot and replace or sister joists and sub floor.

The deflecto says yes to tile, no to stone for 11 feet, but no to both at 12 feet and there are no inbetween settings. If it is not doug fir it is no to both also.

Kirk

[bbcamp]

If you didn't already have to sister some of the joists, and you were going to use either Ditra or Kerdi oon the floor, I'd say you were close enough for gummit work. But you ain't, really. So, get that subfloor out, and sister all the joists with 2x8s.

Removing the 2x8 subfloor will give you room to install a mud floor that you can pitch towards the drain. Use Kerdi and a Kerdi drain so you won't need a final setting bed of mud. Install the subfloor on cleats so it is flush with the tops of the joists and you will have at least 1-1/2" of mud to play with. Once you have the mud sloped properly, set the Kerdi then tile.


For the toilet, set the toilet flange on a pedistal of mud so it is slightly (1 inch or so) higher than the shower drain. Lay the Kerdi over the toilet flange (form a seal with a bead of silicone to seal the Kerdi to the flange), then install a flange extender on top, again using silicone to bond the flange exgender to the kerdi. Don't forget to cut out the Kerdi from the center of the flange!

[Kirk Grodske]

Ok. Now some clarification.

Although the joists span 11'-3" the room is only 55 inches wide(4'-7").

The toilet is on the opposite end of the room from the shower and the room is 90 inches long. So the toilet would be on the high end of the slope of the floor. Do I set the flange an additional inch higher than that?

You said set the sub floor on cleats flush with the tops of the joists. What material for this sub floor?

Then do I put a 3/4" plywood over everything to attach the felt, chicken wire, mud, membrane and mud?

I am not familier with the process for the Kerdit product, so I for this example question, I just used the standard mud process. I will read up on the Kerdi product to see how to modify this process. I am concerned with all the potential uneveness of the sub floor surface, diferental shrinking etc. Since the old joists are dry and the sistered and cleats could be green, the floor surface may become irregular.

Does this process change any, in the shower pan area, other than lower everything to maintain the slope and pitch the floor 1/4" per foot to direct everything toward the drain?

Thanks again for all your help.

Kirk

[bbcamp]

Kirk, the unsupported span of the joists is the concern. The joist will flex even if the load is in the other room. Sorry, but that's the rules.

The toilet simply needs to be higher than the shower drain. It also needs to set level. I suggested 1 inch because I didn't know how far it would be from the shower area. Another guy was doing a similar project with the toilet next to the shower. We wondered how he planned to keep the paper dry!

The cleats can be almost anything. 1x4s, 2x4s, 2x2s. They provide support and a nailing surface for the plywood. Set the cleats 3/4" down from the top of the joists, and set the strips of plywood (face grain perpendicular to the joists) on the cleats, so the top surface of the joists and plywood are flush.

Read up on Kerdi. What Im suggesting is a floating mud floor for the entire bathroom and shower, with enough slope that you won't have to worry about drainage or have a curb. Mud will allow you to get the shape of the floor just right, Kerdi will waterproof it, and the fact that it floats means you won't worry about the framing.