Installing ceramic tile on the floor of a ready for tile shower pan is tricky business to start with because the smallest misalignment will make a puddle and trap water in your shower pan. Even with pre-made shower pans it is best to rub a rubber float or grout float over the tile to be sure it is all in the same plane. Installing them with epoxy mortar is even trickier because the mortar sets so fast and it is so sticky. The good news is that once you trowel out the mortar you are basically building a second pan inside the first which is good since some of the pans out there are prone to developing hairline cracks especially when shipped by freight or package service or if they get dropped or manhandled….unfortuately you can’t see the cracks sometimes. Buyer beware.

ADA Pans can be tricky to get right…. 

First off, a lot of folks have asked me over the years about installing barrier free pans on the second floor. I always feel inclined to ask the logical question about whether there is wheelchair access to the bathroom itself. If the bath is even up one small step, the idea of installing a barrier free shower seems a little useless. Most folks who need a barrier free access later in life are usually in a situation where they need someone to help them in the shower. Often at that point, a wheelchair with a transfer board to a shower chair can make a lot more sense.  If you are thinking of a barrier free pan as an elegant shower solution you may want to just consider first where the inevitable drain overflow would go and how much damage it would do to your home were that to happen.

Construction-wise it is not that simple. Getting the pan flush with the floor is critical. The whole idea of barrier access involves a nice level transition with the main floor with a minimum threshold of one inch. On a concrete floor it can be necessary to chip out the area for the pan in order to get it flush with the finished floor. Raising the main floor area will create a taller threshold at the door to the bathroom so if you need a conforming ADA installation, the floor needs to be lower at the pan area. If the construction is wood then it may be necessary to cut the joists down a bit to fit the shower pan in level with the main floor.

Flashing the joint between the pan and the main floor can be tricky. Sometimes it is best to waterproof the entire floor area along with the pan area since the possibility of having an overflow is as simple as dropping a washcloth over the drain accidentally.

Thresholds are commonly treated with a piece of stone. The stone if its siliconed or epoxy mortared into place can create a small curb that can help keep the water in the pan. There are also the flip up / flip down type of curb that can help keep water in the pan as well.

Grab Bars are always a sensible addition to any shower stall, especially to a barrier free pan. The ADA guidelines are really helpful because they have been refined many times over to meet the needs of the physically challenged person.

Pan Man Out.

Shower Benches…what is the best design for benches…here are a few. Bear in mind you dont need any body’s kit. You just need a good bit of skill at knowing how water moves. If you follow the water downhill in your mind, you can plan out a great installation.

Metal Brackets….there are some prefab corner seat frames that you can bolt to the wall. I am not crazy about these only because when someone sits on the bench while showering a lot of water can collect behind the person sitting and can really sent a lot of water at the bolt connections. If you do a good job caulking and sealing the connections you are probably ok.

Precast forms that you can tile over….generally not a bad concept but you need a flange to go up and under your tile….they really need a flange just like a shower pan to do the job. Exactly how you fasten the pan into place is critical and taping and sealant is critical for these to be completely waterproof before they are tiled. I am not a fan of cornerseats because they also  tend to be small and dont leave much “butt-space.”

Studs & Plywood can make a fine seat if you pitch the entire seat and if you put shower pan liner on the top and get it up and under the tile backer and then out over the tiled face of the bench. I like this system as long as you are using a single piece of stone to cover the liner. Tiling the seat portion of a bench is a bad idea, since the grout joints facing up will eventually let water in. Its a tiny bit tricky to wrinkle the liner at the front edge to make sure the water at the front edge doesnt run behind the tile backer.

Trestle benches are probably my favorite design…if fact they are my design. In a large pan you simply cut three pieces of stone and set the seat after the shower pan and walls are tiled. These are assembled with either silicone rubber caulk or epoxy so it is not necessary to fasten through the tile. By cutting two pieces that stand up on edge and a third that spans across you can build the simplest bench that never leaks. Your two vertical pieces need to be made from plywood patterns that you cut to account for the floor’s pitch and the pitch of the seat. The third piece that goes across to form the bench can be held off the wall to allow water to drain out the back. A  stone fabricator can generally make one of these for a few hundred bucks if he can use his dropped pieces from countertop work. They usually have very little use for these small pieces anyway and are happy to make something from them.

Why do SO MANY PEOPLE HAVE PROBLEMS INSTALLING THESE PANS?
I see posts all over the web about folks having problems with these pans. First off, they are a little flimsy. The pans flex really easy and if you are lucky enough to get one delivered that isnt damaged you will see you have to be careful since they are brittle and crack really easy. They are made of an expanded foam, not too different than a coffee cup, so while they should service you just fine once installed you need to be extra careful handling it. 

Leveling the Pan: Setting the pan in the standard dry set mortar is what some of the manufacturers recommend. If you have a level floor that is best since it can be challenging to get these to level up. Over the years, many folks have asked me the best way to install a Tile Redi Shower pan and I have coached people from all over the country and its funny how there are regional customs with the names…some call them shower pans, shower bases, shower trays, shower receptors. It doesnt matter what you call it. We will get you squared away here.

Dryfit. Dryfit. Dryfit. Dont bull and jam and try to mortar it down and set a rigid shower pan pan all at once…unless you have done a few.  Dryfit the pan in the enclosure to be sure that the hub for the drain is down into hole you cut for it which is usually about 4 1/2″ to 5″…too big weakens the floor around the drain and too tight can mean you have to force the hub down a little…dont do that. Setting a few shims or marking the studs with a pencil line will help you get the pan on the level.

Over Plywood: With this system you really need to have the second layer of plywood in place since the pans can flex around the drains. This is Tile Council of America standard industry practice for subfloor prep….. 1 1/8″ minimum APA grade plywood. Usually 1/2″ of mortar can work well but only if the floor is stiff. I dont understand why the manufacturer wont specify mortars, but be sure to set the pan in the mortar and then remove it to be sure all the ribs have touched down and are wet. Removing one of those Redy to Tile Shower Bases may take two people but it is worth it to be sure you have no dry spots. Touch up the mortar if necessary and re-set the pan and leave it be until it sets if you can. I prefer not to pound the pan down if I already know it is bedded. If pencil marks are put on the studs then you know you are down. You dont want to flex the pan down or weight it down in the middle. Generally the Ready to tile Shower Tray pans dont need fastening to the studs. If you get one that isnt straight you may need to pull the bow out of it with a few screws. I know people do it but it doesnt seem necessary, especially if you are using their flashing installation system. My personal bug is that the flashing costs about $50 extra for a few little pieces of aluminum that you can buy at HD for about $3.
Note: I have heard of instances when people use waxed or waterproof chip board or osb subfloors and set these directly on them and the mortar doesnt set up because the water is trapped between two layers of impermeable material. You need to use a vapor permeable layer on the second layer of subfloor. I have heard of folks using a urethane based construction adhesive or spray foam on the ribs if you can test for adhesion. Some of those expanding foams can force the pan to rise up or even distort out of shape because they are a little flimsy. If this happens you will have hollows under the pan which can be really bad.

On Concrete: I think the traditional dryset mortar method that some manufactiurers recommend will work fine but I also hear from folks who have used the original non modified thinset mortar because it is easier to work with and stays wet a little longer. None of the thinset mortars should be used to build up an out of level floor. On an out of level concrete floor it may be easier to just build up the floor with some dryset mortar and screed it off level and let it set before installing the pan. In any installation, having a level floor is the easiest way to assure a good install.

How do I prepare my subfloor for a Ready to Tile Shower Pan Installation? 

Strength of the joists: Generally the strength of the joists and the joist spacing come first. Most twentieth century construction is adequately rigid and / or strong enough  to support tile. I like to say if it strong enough  and prepared well enough for a direct tile installation then you will have no problem installing any tile shower pan whether it be fiberglass, components or the ready to tile type. Joists which have been cut down, notched or modified in previous remodels can create a springy floor and should be addressed….maybe doubled up or bridged and blocked so they are stiff.

Plywood Floors: Floors are constructed generally in wood homes with two layers with the first layer being 5/8″ or 3/4″ plywood called the subfloor which fastens to the joists. The underlayment goes over that and in most systems the second layer of 1/2″ or 5/8″ plywood makes a floor suitably strong enough for tile. The general rule of thumb is having 1 1/8″ of solid plywood. Gluing plywood to the joists and between layers makes it even stronger. It has become common for builders to install a second layer made of fiber cement or cement board as a second layer.

Board Floors: Tongue and groove board floors or just plain square edge boards on the joists are usually not rigid enough to count as a layer in the floor assembly. In this case it can be fine to put a layer of 3/4″ over the existing board floors but sometimes it makes sense to cut the board floors out if you need to minimize the height of the new floor or you are trying to level the floors. If you can only add a minimum of plywood over a board floor you may want to consider a crack isolation membrane.

Concrete: 4″ to 5″ of concrete is generally a solid slab to install your tile over. Many concrete floors are not level and it may be a good practice to use a pourbale leveling compound to get a good level floor to build on or even to use mortar and screed off the floor to a level surface. Cracks usually are a problem that need to be addressed and there are crack isolation membranes in sheet form or pourable liquids that will prevent the tile from attaching to those shifting surfaces.

Cementboard & Fibercements: These products dont generally add much strength and add some extra dead weight to the floor so they are not my first choice but they work fine. it is typical to use a thinset mortar to install these over your plywood floor.

Uncoupling or Isolation  Membranes: There are waffle type materials out there on the market that are thinsetted down over a plywood subfloor and can be used in place of the second layer of underlayment and they are generally excellent but not cheap. These are great as a crack isolation membrane and they can minimize the thickness of a new floor. There are also liquids that can be painted or poured on to isolate a floor that moves.

Extra Help: There is a third party agency called Tile Council of America which sets standards, or TCA Guidelines for preparation of surfaces for Tile and they have a booklet that is very handy to reference.

What can I expect when I go to hookup a redy to tile shower pan to the existing plumbing system?

Limitations: Unfortunately you are stuck with the standard glue connections on some of  these pans unless you buy the type where you can specify the drain and order it separately.

Standard 2″ PVC socket: Some Shower Pans come with a drain collar that is fused right into the pan making it virtually impossible for them to leak. The drain collar is a 2″ white pvc socket and it can accepts standard 2″ pvc or abs piping. These can really be a bear to hook up if you dont have access below.

Other Piping systems: It depends what kind of plumbing exists under the floor. You are generally going to want to adapt your existing plumbing to PVC. Here are some general guides for adapting if you are stuck with the standard pvc socket type of pan:

Cast Iron: If you are trying to connect to a cast iron hub socket you can use a rubber donut to install a pvc adapter. Cast iron can also be cut off with a diamond grinding wheel and you can adapt a rubber coupling with a stainless band to clamp new pvc pipe to it.

Galvanized Iron: If you have galvanized iron pipe it is probably a good long term decision to replace as much of the horizontal pipes as you can get to any time you renovate. A rule of thumb is that it lasts about 60 years, maybe much longer as vent and vertical piping, but sometimes as little as thirty years in a horizontal application. After about thirty years, this type of pipe accretes on this inside and is virtually impossible to snake out once it fills up with mineral build up.

Copper: Copper pipe used in waste piping will last virtually forever and stays nice and clean on the inside. You can generally adapt to copper by soldering on a threaded adapter or using a rubber & stainless band clamp.

ABS: Black plastic pipe is generally adaptable to the white pvc piping. It simply requires a different, readily available cement to attach the two pipes together called a transition cement.

NOTE: It is generally easier to change the trap along with the vertical pipe that ties into the shower pan. On concrete floors the traps can be very deep underground or just under the concrete. You can run a snake down into the vertical pipe to see how far down the trap is located. If it is not very deep it is sometimes easier to simply bust out the concrete and move the drain to where you need it.

What if one of those Ready to tile shower pans doesn’t come in my size? Do what the designers do….get creative. By thinking outside the box you may be able to include one in your design and enjoy all the benefits of using a ready made unit. I usually dont worry about saving a day or two in the schedule if you are looking at a bath that will serve you for thirty or more years.

1. Change the framing….simply deconstruct one of the adjacent walls and move it where you wished it was. A professional carpenter can do this task without too much trouble.

2. Turn wall studs flat….if you only need an inch or two you can often times remove 2×4’s and turn them the flat way to pick up 2 inches.

3. Notching studs…..if you are only missing by a half inch or an inch you can sometimes cut a small notch in the studs to make a pan fit under the wall slightly.

4. For a pan that’s too small by an inch or two you can add furring strips to the existing studs to make the framed space smaller……this is also a good time to make everything straight and plumb.

5. For a pan that needs a few inches down one side you can build a short knee wall that can serve as a soap ledge and cap it with a piece of stone. Be sure to waterproof the top with liner or membrane.

6. If you are trying to fill in 12 to 20 inches at the end or side of a pan you can build a bench to sit on. Be sure to waterproof the top. A stone slab is usually the easiest way to finish these off.

7. Building a bench within the pan can be done easily by building a trestle bench which is nothing more than 2 pieces of stone set vertically with a broad piece laid across. Takes some skill & planning.

8. Turn a shower pan diagonally in a large room…this opens up a huge range of possibilities like his and hers benches and display pedestals for sculptures.

A lot of people look at an existing tile shower pan and just dont understand what they are looking at. its pretty simple….underneath all the tile and mortar construction there is a lining of lead, copper, or plastic that is typically nailed right to the studs. If there is a pan being replaced then it usually falls into a range of some typical dimensions and these dimensions are usually taken from stud to stud. The common mistake is to measure between the tile walls rather than to the studs. The question always comes up…how do I know how thick the tile is.

If your house is built after about 1970 or so,  you will typically have a thin 1/2 thick gypsum board with the tile glued to it and your wall thickness will be just  less than 1″ based on the use of 3/8″ thick tile.

If your house is built 1930 then you will usually see tile that was installed over a mortar bed that was troweled onto wire lathe of some type and the thickness is usually about 1 1/2″

If you house is built before 1890 or have a full-on old fashioned mud job you will usually see thicknesses of mortar and tile that can approack 2″ thick. These are just guides to wall thicknesses but they could be helpful.

I have found it really helpful to break a hole in the shower walls up high above the splash line and then i am able to see inside the wall cavities with a light and a mirror . That way you can anticipate wires, pipes, blocking and anything else that could slow down rebuilding once its all torn out and you start to rebuild.