So you are installing a new bathroom and have suddenly hit a snag. Which should go in first, the flooring or the bathtub?
The short answer is that standard bathtubs such as alcove and corner bathtubs should always be installed first, before the finished flooring. The complete answer depends on the type of bathtub, because a freestanding tub and a drop-in both need work done to the floor before they can be placed.
That rule is not about convenience or aesthetics. For a standard tub it is about waterproofing, and the reason is mechanical. For a freestanding tub there is a second, finer rule underneath it that most guides miss, including the earlier version of this page: the finished floor goes down before the tub is set, and the tub's exact position has to be locked before the floor goes down. Those are two different moments, and collapsing them is how people end up cutting new tile open.
The Order, by Tub Type
| Tub type | What goes first | When the position stops being changeable |
|---|---|---|
| Alcove or corner | Tub, then wall board over the flange, then the finished floor | When the flange is fastened to the studs |
| Drop-in | The deck or platform, then the tub into it, then the finished floor | When the deck opening is cut |
| Freestanding | The finished floor, then the tub is set on it | Earlier than you think, when the drain rough-in is set, before the floor |
| Clawfoot | The finished floor, then the tub is set on it | Same as freestanding |
| Shower only, no tub | The pan and the walls, floor with or just after | When the pan drain is set |
What order does yours go in
Three questions. The answer includes the moment the tub position stops being changeable.
Why a Standard Tub Goes In First: The Flange
This is the real reason, and it is worth understanding rather than taking on trust, because it also tells you how to spot the job being done wrong.
An alcove or corner tub has an integral nailing flange, a flat lip standing up along the edges that meet the wall. The tub goes in first and is fastened to the studs through that flange. Then the backer board and the waterproofing are installed lapping over the flange, so water running down the wall sheds onto the outside face of the flange and into the tub.
It works exactly like roof shingles. Every layer sheds water onto the face of the layer below, and the tub flange is the bottom layer, so the water ends up where you want it.
Fit the wall first and that logic reverses. The board ends up behind the flange or flush with it, and every shower after that feeds water down the back of the flange into the stud bay. You will not see it happen. You will see the consequences a few years later, in the framing.
There is a second, practical reason that follows from the same thing: fastening the tub to the studs first is how you establish its exact position and height, which is what lets the backer board be cut to land just above the tub deck rather than resting on it.
If you want the waterproofing layers in full, our guide to waterproofing a bathroom properly covers what sits behind the finish, and the check below walks the lap order for your specific wall build.
Which layer goes over which
The flange lap is the reason a standard tub goes in first. This is how to check it is being done right.
The Other Reasons to Install a Standard Tub First
Real, and secondary to the flange.
Tub type determines the approach
Your bathtub type largely determines how you install it. An alcove or corner tub benefits from going in first because you can position it properly and get a clear sense of the surrounding floor and wall, so everything finishes flush to the tub. A drop-in needs a recess or deck constructed before it can be placed at all, which is a different sequence rather than a variation on the same one. Our guide to bathtub types covers which is which.
Protecting the new floor
If the tub goes in first, the surrounding floor and wall finishes go on afterwards and are never at risk. Manoeuvring a heavy object across a finished floor is how new tile gets chipped and new vinyl gets torn, and a cast iron tub is heavy enough that two people concentrating on not dropping it are not also watching the floor. Our guide to moving a bathtub covers doing it without damage if you have no choice.
A tighter junction
Placing the tub before the floor and wall lets you bring both finishes up to the tub rather than trying to slot a tub into a finished opening. That means smaller gaps, and smaller gaps mean less moisture and debris trapped in them, which matters for the longevity of both the tub and the house. The joint itself should be sealed with silicone rather than grout, and our guide to choosing caulk or sealant explains why that joint moves and grout cracks.
Freestanding and Clawfoot Tubs: Floor First, Position Even Earlier
Here is where the earlier version of this page was wrong, so it is worth being precise.
It said that once the flooring and walls were done, you could place a freestanding tub wherever you wanted without worrying about a complex installation. You cannot. A freestanding tub's drain and supply come up through the floor, which means the holes have to be in the right place before the floor is finished.
Set the drain rough-in and the supply positions to the tub's exact location, at the right height for the trap to sit below the finished floor, and do it before the floor goes down. Decide the position after tiling and the tile has to be cut open to get the drain body and trap below floor level.
Trade guidance on this is unambiguous: the rough-in needs to be correct before the floor above is finished, unless you are prepared to open the ceiling below to reach it. An estimated stub-out height is the other common way it goes wrong, because the trap ends up with nowhere to sit once the floor build-up is accounted for.
So the honest sequence for a freestanding tub is:
- Subfloor level. A freestanding tub must sit dead level to drain properly, and levelling a subfloor is far easier than levelling a finished one.
- Choose the actual tub, then mark its exact position on the floor. The drain location is a property of the specific tub, not a generic dimension.
- Rough in the drain and supply to that mark, at the correct height.
- Confirm the trap fits the depth you actually have, allowing for floor build-up.
- Waterproof and finish the walls.
- Finished floor, cut around the penetrations.
- Set the tub, connect, and seal around the base.
Our guide to installing a freestanding bathtub with the Badeloft EZ Drop-in Drain walks the connection itself, and what a freestanding bathtub is covers the format more broadly.
Clawfoot tubs
A clawfoot follows the same rule with one difference in your favour: the floor is visible underneath it, so the plumbing is generally exposed and reachable rather than buried. That makes a small positional error recoverable in a way it is not with a skirted freestanding tub sitting flat to the floor.
It does not make the position free. The supply and waste still have to arrive in roughly the right place, and exposed plumbing that arrives at an awkward angle is permanently visible. Our guide to clawfoot bathtubs covers the format, and the faucet needs planning at the same time rather than afterwards.
What Is Under Your Floor Changes the Stakes
The order does not change. What changes is how expensive a mistake is, and the earlier version of this page did not mention it at all.
| Beneath the bathroom | If the drain lands wrong |
|---|---|
| Crawlspace or basement you can get into | Usually adjustable from below without disturbing the finished floor. This is the forgiving case |
| A finished ceiling below | Either lift the new floor or open that ceiling. Both cost real money |
| Concrete slab | The drain is cast or cut in. Moving it means breaking concrete, and there is no access from below at all |
On a slab or above a finished ceiling, the rule is simple: do not let anyone rough in a freestanding tub drain before the actual tub is on site and measured. Catalogue drain positions and delivered drain positions are not always the same.
Shower Only Setups
A shower only setup benefits from having the flooring installed first or at the same time, since the shower pan and the room floor are usually tiled as one job. That leaves only the door and the faucet trim to fit once the rest of the bathroom is finished.
You can also pair a freestanding tub with a shower to get both functions in one space, using a curtain or a screen and a removable faucet. It is a genuine option and it is a compromise: a shower over a freestanding tub needs an enclosure that works against the reason you chose the tub. On whether the trade is worth it, our guide to bathtubs versus showers and resale value covers what a combination does for a home's appeal, and our guide to the tub surround covers enclosing it properly.
Common Questions
Do you install a bathtub before or after flooring
Before, for an alcove or corner tub, because the wall board has to lap over the tub's flange to shed water into the tub. After, for a freestanding or clawfoot tub, because it sits on the finished floor. A drop-in needs its deck built first.
Do you tile the bathroom floor before installing the bathtub
Not for a standard alcove tub. The tub goes in first and the floor tile is brought up to the tub apron afterwards. For a freestanding tub, yes, the floor is tiled first, but the drain position must already be set.
Should the cement board go over or behind the tub flange
Over it, cut to land just above the tub deck rather than resting on it. Board behind the flange sends water into the wall cavity, and board resting on the deck wicks water and leaves no room for the joint to move.
Can you install a freestanding tub on an existing tiled floor
Yes, and the existing drain position then constrains which tub you can buy. Measure from the drain centre to two walls and shop for a tub whose drain falls in that spot. Fighting it means cutting the tile.
Does the subfloor go in before the bathtub
Yes. The subfloor is structural and the tub sits on it. The sequence is subfloor, then tub, then wall board lapping the flange, then the finished floor. Check the subfloor is level before the tub goes down, because shimming a tub is easy and levelling a finished floor is not.
What happens if the flooring was installed first by mistake
If the walls are still open, not much. Set the tub on the existing floor and board over the flange as normal, and you lose only the neat floor-to-apron junction. If the walls are already boarded and tiled down to the floor, do not just slide a tub in and caulk the gap, because water will get behind the flange. Cut the board back above the tub deck line and re-lap it.
Does it matter for a bath with no shower
Less, and the order is still worth following. A bath with no shower over it only takes splashes rather than a stream running down the wall, so the flange lap is doing less work. It costs nothing to get the order right and it protects you if a shower is ever added.
The Rule, Restated
There is a right answer here, and it is decided by the tub rather than by taste.
A standard alcove or corner tub goes in before the finished flooring, because the wall board and waterproofing have to lap over its flange to shed water into the tub rather than into the wall. A freestanding or clawfoot tub goes in after the finished flooring, because it sits on top of it, and its drain position has to be set before that floor goes down. A drop-in needs its deck built first.
Get the order right and the bathroom lasts. Get it wrong on a standard tub and the failure is inside the wall where you cannot see it, which is the worst kind.
If you are still choosing the tub that decides all of this, our stone resin freestanding bathtubs and our bathroom sinks are where to start, and our guide to why bathtubs crack covers what poor support underneath does to a tub over time.