Tile Ready Shower Pan or Built-Up Pan? What to Ask

A tile ready shower pan and a built-up pan are two ways to build the same thing: the sloped, waterproof floor under your shower tile. One shows up already shaped. The other gets shaped in the bathroom. So don’t choose by name. Choose by asking which one is planned, how it gets waterproofed and sloped to the drain, and what the local building department inspects.

That matters because a shower floor that isn’t sloped to the drain, or isn’t waterproofed, can be hard to fix once the tile is set. Settle it with your installer and the design team before the floor gets built. Neither choice gets you out of the code or the inspection.

What Is a Tile Ready Shower Pan?

A tile ready pan arrives already sloped. One shower-system maker builds prefabricated sloped shower trays like that. Tile goes over the top. The slope isn’t shaped in your bathroom. It shows up that way.

On one shower-system maker’s page, the maker describes its prefabricated sloped trays as having waterproofing built in. The maker also says they do away with the need for a mortar bed. It calls them “Waterproof and ready to tile.”

That’s one maker’s description of one product line. Other ready-made pans may differ, and so may the instructions that come with them. So ask which product is planned for your shower. Then read its instructions.

What Is a Built-Up Shower Pan?

A built-up pan gets built in place. The Tennessee Residential Code 2018 calls that an on-site built-up shower receptor. The code text says the adjoining walls and the floor framing around it must be lined with a listed material. The sloped floor is then finished over that lining. The shape is made in your bathroom.

Guthrie’s post on what happens during a tub-to-shower conversion lists the pieces: a sheet or liquid membrane with every seam treated, and either a sloped mortar bed or a pre-formed base.

Which approach suits a plan is a design question. The design team can explain how each one fits a bathroom layout. Picture a shower where the drain needs to move. That single change can ripple into the floor. So ask early, before anything gets built. Once the tile is set, changes can get hard.

What Does the Code Ask of Any Shower Floor?

The Tennessee Residential Code 2018 covers shower receptors in a section of its plumbing chapter. It sets what a shower floor must do, whichever way that floor is built. The finished floor has to slope to the drain. The drain has to be an approved flanged one. A finished curb has limits. The method isn’t the point.

Under the Tennessee Residential Code 2018, the finished floor must slope uniformly toward the drain. The slope has to be at least two percent and no more than four percent. In everyday terms, that’s roughly a quarter inch to a half inch of drop for every foot of run. The code text also calls for an approved flanged drain. It goes in with the shower subpan or lining, and its flange has weep holes into the drain.

A finished curb has its own numbers in the code text. The curb must be not less than two inches deep. It can’t be more than nine inches deep. That’s measured from the top of the curb to the top of the drain. The code text also says a finished curb threshold sits not less than one inch below the sides and back of the receptor.

For on-site built-up receptors, the code text lists the lining materials: sheet lead, sheet copper, a plastic liner, hot-mopped felt, or a sheet-applied bonded waterproof membrane. That lining has to reach not less than two inches above the finished threshold.

Does the Code Pick a Winner?

No. The chapter describes what a shower receptor must do, and how an on-site built-up one gets lined. It doesn’t use the phrase tile ready. It doesn’t rank the two systems. So the code text won’t settle this choice for you. It sets the job the finished floor has to do.

How a particular ready-made pan is treated is a question for the installer, the product’s instructions and the local building department. No product page can answer it for your address. That’s the conversation to have before the floor goes in, not after. Ask the installer how the chosen pan will be handled. Ask what gets shown to the building department.

Those numbers are the text of the Tennessee Residential Code 2018 as published. Another edition can read differently. So can another state. A local amendment can change what applies on your street. Your address decides which text an inspector uses, so treat these numbers as a starting point and confirm what applies where you live.

Ask These Questions Before the Floor Goes In

Don’t wait until the tile shows up: ask the installer or the design team these before anyone starts the shower floor.

• Which shower floor system is planned for this bathroom, and why that one?
• How will the floor be waterproofed, and how will it slope to the drain?
• Where does the drain sit, and does the floor plan move it?
• What will the local building department want to inspect, and at what stage?
• Who checks the shower floor before any tile goes on?

Guthrie’s post on the order a bathroom remodel follows says the shower pan gets waterproofed and flood-tested before a single tile touches it.

Frequently Asked Questions About Shower Pans

Is a ready-made pan already waterproof?

The maker says its prefabricated trays have waterproofing built in, and the maker’s page calls them waterproof and ready to tile. That’s one maker’s claim about one product line, not a rule for every ready-made pan. Ask for the instructions that come with the product being planned. Read what they say about the seams, the drain and the walls. Then ask your installer how those instructions will be followed.

What does built-up mean in the code?

The code text refers to on-site built-up shower receptors. For those, the adjoining walls and the floor framing that enclose the receptor must be lined with one of the materials the code text lists. That lining has to reach not less than two inches above the finished threshold. So built-up points to a receptor assembled on site.

How much slope does a shower floor need?

The code text says the finished floor must slope uniformly toward the drain, not less than two percent and no more than four percent. In plainer terms, that’s roughly a quarter inch to a half inch of fall for every foot of run. Those are the figures in the Tennessee Residential Code 2018 as published. Another edition or a local amendment may set something else, so confirm what applies at your address.

Who decides whether my shower floor passes?

The local building department does. It applies the code edition and the amendments adopted at your address, and those can differ from one place to another. So ask it before the floor is built, not after the tile is set. The installer and the design team can tell you what they plan to show the inspector. That’s a good answer to have while the shower is still on paper.

Will Guthrie help me choose a shower floor?

The design team helps homeowners get the most out of a bathroom layout, and a shower floor is one piece of that plan. The Pleasant View showroom lets you see materials in person. You can visit the showroom or schedule a consultation, then bring your shower plan into that conversation. If you’ve got a drawing and product instructions, bring them too.

Bring Your Shower Plan to the Showroom

At Guthrie’s Pleasant View showroom, you can see materials in person, from cabinetry and countertops to plumbing fixtures.

So is a tile ready shower pan the right floor for your plan? That depends on the answers you get: which system is planned, how it’s waterproofed and sloped, and what the building department inspects. As a general rule, get those answers first. The design team can help you ask the questions.

Planning a bathroom remodeling project? You can visit the Pleasant View showroom to see materials in person, or schedule a consultation to get started.

Before a tile ready shower pan or a built-up pan goes into your bathroom, talk with Guthrie’s design team about your shower floor.