A 200 × 200 mm tile is a nominal label, not a measurement. The dimensions that decide whether your grid works are the ones associated with the offered caliber — the supplier’s size-group code for tiles sorted into a narrower band after firing — and you need those dimensions, in millimeters, for the specific lot being quoted. Squareness matters alongside size because two tiles can measure identically across their faces and still produce a wandering joint line if the corners are not true, so a dimensional discussion that covers only length and width leaves half the question open.
Checking 200 × 200 mm tile caliber and squareness before shipment is a matter of comparing representative pieces from the offered lot on a marked grid, recording what you find against identifiable carton and sample references, and agreeing in advance what the inspection represents.
Separate Nominal Size from the Offered Caliber
| Information in the offer | What it tells you | What to establish for the offered lot |
|---|---|---|
| Nominal size: 200 × 200 mm | The catalogue size label | Keep this label separate from the working dimensions. |
| Caliber code | A supplier code whose meaning needs clarification | Ask for the code meaning and the actual size information associated with the offered lot. |
| Working dimensions | The dimensions used to coordinate the tile grid | Record the offered dimensions separately from the nominal size. |
Treat the size on the catalogue page and the size you will build with as two different fields in your records, and never let one overwrite the other. The nominal 200 × 200 mm is a naming convention shared by many products from many factories; the caliber code tells you which sorted size band the fired tiles fell into, and only the supplier can tell you what that code means in actual dimensions.
The mechanism behind this is straightforward. Ceramic bodies shrink during firing, and the amount of shrinkage varies within a kiln load and between loads, so finished tiles are sorted into size groups and marked accordingly. Two cartons of the same article number, same shade and same finish can belong to different calibers and will not lay into one continuous grid without the joint absorbing the difference. When you request a quotation, ask for the code meaning and the actual size information for the lot being offered, and write those working dimensions into a field of their own.
Carton markings are where this information usually surfaces on arrival, and shade, caliber and batch codes often sit together in the same block of text. If you cannot connect a dimensional observation back to a specific carton code, the observation stops being useful the moment the pallet is broken down. Confirm what each code on the packaging denotes before you start measuring anything.
A practical consequence for installation: the installer sets out the grid from the working dimensions plus the joint width, not from the catalogue size. If you supply only the nominal figure to the site, the setting-out will be nominal too, and the error accumulates across a run of tiles until it shows up at a wall, a threshold or a drain.
Make Dimensional Comparisons Traceable
A dimensional figure is only comparable when you can say which sample it came from and how it was taken. When you are weighing two proposed lots or two products against each other, build one comparison sheet that carries the lot reference, the carton reference, the sample identity and the results side by side, and use the same measuring approach throughout — same instrument, same points on the tile, same operator where possible.
The reason is that a difference in measuring technique produces a difference in numbers just as readily as a difference in product does. If one set of readings was taken with a steel rule across the face and another with a caliper at the edges, the two sets are not evidence of anything about the tiles. Fixing the method is what lets you say a variation belongs to the product rather than to the check.
This kind of buyer check is a commercial screening tool, and it should be described that way in your records. Where formal conformity is at issue, the determination of dimensions and surface quality for ceramic tiles is covered by its own test procedure in Azulejos cerámicos – Parte 2: Ensayos de solidez del color frente a la luz, which sets out the public scope of how those dimensional characteristics are measured. An improvised measurement on a warehouse bench does not substitute for that procedure, and any numerical tolerance, lot result or installation acceptance limit has to come from the agreed product requirements rather than from the standard’s public summary.
Keep the sheet simple and keep it complete. A row that records “lot B, carton 4, sample 2” with its readings is worth more six weeks later than a tidy average with no traceability behind it. When you raise a question with the supplier, those references are what let the factory look at the same material you looked at.
Check Rectangularity and Edge Alignment in a Dry Layout
Lay representative pieces out dry on a marked grid before you form any opinion about squareness, because a single tile held in the hand tells you very little about how corners will meet. Mark the grid with the proposed joint width, assemble several rows and columns, and look along the joint lines from a low angle where deviation becomes visible.
Two distinct dimensional characteristics produce the irregularities you will see. Rectangularity is whether the corners are true right angles; a tile that is slightly rhomboid will close one end of a joint and open the other, and the effect compounds as you add tiles in the same direction. Edge straightness is whether the sides are flat rather than bowed or waisted; a curved edge opens a lens-shaped gap in the middle of an otherwise acceptable joint. Separating the two is what allows you to put a precise question to the supplier instead of reporting that the joints look wrong.
When something in the layout looks irregular, ask for a dimensional assessment that covers rectangularity and edge straightness specifically, referenced to the offered lot. That request is much easier for a factory to act on than a general complaint, and it tells you whether the characteristic is within the product requirements you agreed.
One caution on interpretation: a dry layout on a flat bench isolates the tile. On site, the substrate flatness and the setting-out itself also shape what the finished joint looks like, and a wavy screed will produce joint irregularity with perfectly square tiles. Assess the substrate separately rather than attributing every installed defect to the tile.
Test Plain and Decorative Lots on the Same Grid
If a decorative tile has to run continuous joints with a plain field, lay pieces from both offered lots together on one grid at the proposed spacing and carry the layout across several rows before you accept either. Decorative pieces are often produced in a different run, sometimes with additional processing after the first firing, and they can belong to a different caliber even when the article is sold as a matching companion to the plain tile.
Checking a single pair of adjoining edges will not reveal the problem. A small per-tile difference is invisible at one joint and conspicuous by the fifth, because the pattern field and the plain field drift apart along their shared line. Running the dry layout across several rows in both directions is what converts a dimensional difference into something you can actually see and judge against the appearance you are selling.
The exception worth knowing is a design one. If the decorative work is detailed as an independent panel — a framed insert, a band with its own perimeter joint or a border separated by a trim — then the grids do not have to agree, and the perimeter detail absorbs the difference. That is a decision to settle at the drawing stage, because it changes what you need to check and what you need to specify.
Agree Sampling and Resolve Dimensional Concerns
Settle the lot definition, the sampling plan, the characteristics to be checked and the acceptance basis before the shipment inspection takes place, not after a few satisfactory samples have given everyone confidence. Sampling is what determines the scope of what your check represents; pieces pulled from the top of two accessible pallets describe those pallets, and nothing more. Baldosas cerámicas – Parte 1: Requisitos para las baldosas cerámicas sets out the public framework for ceramic-tile sampling and the basis for lot acceptance, but the lot definition, inspection level and purchase acceptance terms are commercial matters you and the supplier have to agree in writing.
A clear acceptance basis also gives the contract somewhere to go when a result falls outside the agreed product requirements. Without one, a dimensional disagreement becomes a negotiation with no reference point, usually at the worst possible moment in the project schedule.
If a dimensional concern survives your check, keep the affected lot identifiable — cartons unmixed, references intact, the sampled pieces retained — and send the supplier your recorded observations, the sample references and the intended layout together. The layout matters because the same dimensional variation is trivial in a wide-joint utility floor and unacceptable in a tight-joint feature wall, and the supplier cannot weigh the finding without it. Hold release to installation until that exchange has taken place.
The failure to avoid is quiet adjustment on site. Widening the joint or shuffling cartons to blend the variation removes the evidence, makes the original question unanswerable and often creates a new appearance problem in place of the old one. Where a project chooses an alternative layout as the remedy, that disposition belongs to the project’s approved procedure and its designated approver, documented after the responsible parties have reviewed it — it is not an installer’s decision at the trowel.
For a productive conversation with the supplier at this stage, have ready the article reference and the caliber codes on the offered cartons, the working dimensions you have recorded, the joint width and setting-out direction you intend to use, the quantity and the area it covers, and whether a decorative tile shares the grid.
Preguntas frecuentes
Q: Can I substitute another 200 × 200 mm tile without changing the planned layout?
A: The nominal size alone is not enough to approve a substitution. Compare the working dimensions and caliber information for the offered lots, then dry-arrange representative pieces with the proposed spacing. Where decorative and plain tiles must share joints, check the alignment across several rows before accepting the change.
Q: Can a few satisfactory samples be the basis for accepting the whole shipment?
A: Not by themselves. Before shipment inspection, agree which lot is being assessed, how samples will be selected, which characteristics matter and what acceptance basis applies. Keep sample and carton references with the observations so the result can be linked to the material being accepted.
Q: Do uneven joints in a trial layout mean the tiles should be rejected?
A: That observation alone does not settle acceptance. Record the affected pieces and layout, then obtain a dimensional assessment covering rectangularity and edge straightness against the agreed requirements. For an installed area, assess the substrate and layout separately rather than attributing every irregular joint to the tiles.
Q: Can we resolve a dimensional concern simply by widening the joints or mixing cartons?
A: Do not treat either change as an automatic resolution. Keep the affected lot identifiable and preserve the original observations before changing the arrangement. A different layout may be acceptable after the responsible parties review it and document the project disposition; resolve that decision before releasing the material to installation.