This checklist turns a shower base and door purchase into an ordered plan: measure the finished opening first, lock the base footprint and threshold second, match the door's track and mounting to that threshold third, and confirm the installation order before either product is delivered. Each step produces a number or a decision that the next step depends on, so the checklist should be run top to bottom rather than jumped into at the door selection stage. When the last box is checked, the base and door are known to fit before they arrive.
The base and door are the two parts of the enclosure most likely to be ordered separately and fail together: a door that fits the room width can miss the base threshold, and a base with the perfect footprint can leave no mounting line for the door. This checklist exists so the mismatch is found on paper, not at the end of installation day.
Why This Planning Sequence Prevents Mismatches
The sequence follows the dependency chain of the enclosure. The finished opening is the master dimension, because both the base and the door must fit it. The base then adds its own constraints, the footprint and the threshold, which the door must respect. The door is the most flexible part of the chain, so it is chosen last, against the numbers the base and the walls have already set. Running the checklist in this order means each decision is made against facts that will not change later.
The checklist also protects the schedule. A base ordered before the opening is measured, or a door ordered before the threshold is known, turns into a return or a plumbing change that stalls the bathroom. The ten minutes the checklist takes on paper save the week that a mismatch costs on site.
Finished Opening and Site Facts to Record
- Finished opening width measured at the back, middle, and front between the finished wall surfaces; record the tightest value.
- Finished depth measured from the back wall to the planned front edge at both ends and the center.
- Wall plumb and corner square checked at the base zone and the door mounting lines.
- Subfloor level, flatness, and structure checked under the base footprint.
- Drain position measured from two finished walls, with the pipe size and connection type noted.
These five facts are the site evidence every later choice uses. Record them on a drawing with the walls labeled, and keep that drawing as the reference for the whole project, because the base and door specs will be compared against these numbers.
Take the width readings at three heights and the depth at both ends because walls and floors are rarely perfect: the tightest point is the number the products must fit, and a single center reading hides the corner that will fight the base later. A tape measure, a level, and a straightedge are the whole tool kit, and the drawing should note which walls were used as the reference for the drain offsets so every later measurement uses the same origin.
Base Selection Checks
- Base family chosen for the opening class, with the actual footprint compared with the finished opening.
- Threshold profile selected for the household's step-over needs and the planned door type.
- Drain option, center, left, right, or offset, matched to the measured pipe position.
- Threshold width and height read from the base specification.
- Installation method confirmed: mortar bed, foam support, or the product's specified system.
At this stage the base is chosen but not yet ordered, because the door compatibility checks in the next step can still change the base's threshold requirement. The base's threshold specification is the bridge between the base and the door, so it is recorded even before the door model is picked.
Compare the base's actual footprint with the recorded opening rather than its nominal label, and note the installation tolerance beside the numbers. A base that fits the nominal opening on paper but exceeds the tightest measured point is a return waiting to happen, so the spec-sheet footprint, not the product name, is what the checklist compares with the drawing.
Door and Threshold Compatibility Checks
- Door type chosen: sliding, hinged, or pivot, with the mounting method read from its installation drawing.
- Track or pivot width compared with the base's usable threshold width.
- Threshold height compared with the door's bottom track and sweep requirement.
- Door height measured from the top of the threshold to the surround top or track line.
- Wall mounting surfaces confirmed solid at the hinge, clip, or track positions.
When the door's mounting hardware fits the base threshold and the walls carry the door, the pair is compatible. If any check fails, the fix is chosen here, a door with different hardware, a base with a different threshold, or a mounting method change, before either product is ordered.
Door lead times make the order of this step practical as well as technical: if the door is made to order, its production time should overlap the base installation rather than follow it, so the checklist includes confirming the door's lead time against the install schedule. Choose the door family early, confirm the base threshold early, and place the final door order only when the finished measurements are recorded, so the wait and the fit stay aligned.
Installation Order and Pre-Finish Checks
- Prepare the floor: level, flat, solid, and dry within the base's tolerance.
- Set and level the base, connect the drain, and test the connection while the underside is accessible.
- Let the mortar or support and all seals cure for the time the manuals require.
- Build the wall finish over the base flanges and complete the corner and threshold seals.
- Measure the finished opening from the installed base and finished walls, then order or finalize the door.
The installation order is part of the planning checklist because the door size depends on it: the door is measured after the base and walls are in place, so the schedule has to allow the base install and wall finish to happen before the door order is finalized.
Protect the base through the finish stages by covering it while the walls are tiled or paneled and while the door hardware is installed. The base is the surface that takes the heaviest daily abuse, and a scratch or a chip at the threshold collected during construction becomes a permanent flaw in the finished shower, so the checklist includes a protection step between the base install and the final cleanup.
Running the Checklist Before You Order
- Open the site drawing and confirm the finished opening numbers are recorded.
- Compare the base's actual footprint and threshold spec with those numbers.
- Compare the door's track and mounting dimensions with the base threshold.
- Confirm the wall finish plan and the installation order on the schedule.
- Order the base and door only after every line above passes.
When the checklist passes end to end, the base and door are planned as one system rather than as two guesses. For the full system compatibility framework, see the complete system compatibility guide.
Re-run the checklist whenever a decision changes, whether it is a different base model, a new door style, or a wall finish swap. The numbers interact, so a change at any step can invalidate a check that passed earlier, and the checklist only earns its place if it is updated with the final decisions rather than filled in once and forgotten.
Frequently Asked Questions
Should the checklist be run before or after demolition?
Run it in two passes: before demolition to plan the base and confirm the site facts, and again after the old base is removed and the subfloor and drain are exposed. The second pass finalizes the order with the real numbers.
Which step of the checklist matters most?
The finished opening measurement is the master step, because the base and the door both depend on it. The threshold-to-track check is the second most important, since it catches the mismatch that width alone cannot see.
Can the checklist be used with a curbless base?
Yes, with one addition: confirm the floor height outside the shower and the door's low-edge mounting method. Curbless entries change the threshold reference, so the checklist's threshold checks are adjusted to the near-level line.
What if the door and base checks disagree on width?
Resolve the disagreement before ordering either part: adjust the door's track or mounting, change the base threshold, or alter the opening. Do not order to the larger number and expect the install to absorb the difference.
Who should keep the completed checklist?
The homeowner and the installer should both keep it, with the site drawing and the product specs. When the door fitter arrives weeks later, the checklist answers how the base, threshold, and opening were planned without reopening the decisions.
Measure the opening, lock the base threshold, match the door hardware, and verify the install order before ordering either product. Begin with the Shop Shower Bases collection once the checklist is on paper.