Buying cement tiles is a nice decision... until it comes time to calculate quantities. That's where the real problems often arise: missing boxes, unplanned cuts, mismatched borders, forgotten skirting boards, last-minute changes and, most frustratingly, shade differences due to production in another batch.
This guide is designed to give you total clarity before you order. And if you are with a professional, it will help you to speak the same language and validate that the order is well thought out.
1) Start with what is important: what surface are you going to tile or pave?
It seems obvious, but most errors come from here.
- Draw a sketch (even by hand) from the floor or wall.
- Divide the space into simple rectangles.
- Calculate the area of each part and sum.
- Subtract only what is not really to be covered (e.g. large permanent gaps).
If the space is irregular, dividing into sections is the safest way (and the one used by installers).
2) The golden rule: don't buy “by the metre”, buy on margin.
In industrial ceramics it sometimes fits very well. On cement tile flooring, it does not.
As a general guide to the sector:
- +10% margin for straight installation and “clean” rooms (few cut-outs).
- +15% margin if you place diagonally, There are too many starters/salts, or the design calls for more cuts.
That margin covers:
- Cuts
- Breaks
- Parts that stain on site
- Perimeter adjustments
- Save some parts for future repairs
Quick example
You have 24 m² of floor space:
- Straight: 24 × 1,10 = 26,4 m² (round up)
- Diagonal/complicate: 24 × 1,15 = 27,6 m²
3) The “trick” that almost nobody considers: the boss rules (and can make it more expensive).
With cement tiles, calculus is not just mathematics: it is composition.
If your design is a “carpet” design (frame + centre)
This is where it fails the most:
- The framework consumes edge pieces and generates offcuts.
- The corners may require specific parts or drawing planning.
Our recommendation: before ordering, define:
- Where does the pattern begin?
- Which edge is left “whole” in view?
- Where do you accept cut-outs (under furniture, under the sink, behind the door)?
If this is decided late, the actual margin is shot.
4) How to calculate borders and edges (no surprises)
For borders/edges, it's all about the perimeter, not the area.
Practical method (widely used in edge calculation):
- Add the sides where the border will go (in linear metres).
- Divide by the “length” that each border piece covers (e.g. 20 cm = 0.2 m).
- Add margin for cuts (normally a margin is left and the door is not discounted, because there are cuts).
This prevents you from falling short on the most visible detail.
5) What if you buy in boxes? The step that saves you mistakes
If your product is served by cement tiles boxes, the final calculation is always:
boxes required = (total m² with margin) ÷ (m² per box) → round up
And here comes the important part: always round up, because one box less is the typical mistake that paralyses a construction site.
6) Differences in tone and batches: why you should get it right first time
Handmade cement tiles have natural shades. That is part of its charm. But it means that:
- If you ask for an extra weeks later, you can have tone variation.
- Sometimes that small change is just in the most visible area.
Therefore, the margin (10-15%) is not “just in case”: it is a strategy of aesthetic continuity.
7) Final checklist before ordering (what I would definitely check)
- Plan/sketch with actual measurements
- Type of installation: straight / diagonal
- Areas with more cuts: pillars, steps, doorframes
- Will there be a “carpet”, frame, border or plinth?
- Is anti-slip required in any area (shower, outside, entrance)?
- Defining joints and alignments with the installer
- Be clear about the sealing and protection system (especially in wet areas).
If you want to go deeper into installation and protection (very relevant to avoid stains on site), your own guide fits perfectly as an internal link.
Frequently Asked Questions (FAQ)
How much margin should I add if I don't know how it will be placed?
If you have not yet decided, the prudent thing to do is to 15%, especially if there are possibilities of diagonal or complex cuts.
Can I order only “just enough” and keep zero left over?
It is not recommended. Leftovers are not waste: they are insurance (future repairs and continuity of tone/batch).
Is the border calculated per m²?
No, the border is calculated by linear metres (perimeter) and is adjusted by the width of the workpiece.
What if my room has many entrances and columns?
More cuts = more real waste. Here the 10% falls short: better 15% or more according to complexity.
Need help choosing your cement tiles?
Contact us We will help you choose your perfect design and validate the required surface area before manufacturing or preparing the order: with a sketch (even a simple one) we can recommend the optimal margin, the placement logic and the finishing details so that the final result is clean, balanced and durable.
