Laying tile on a 45° diagonal: mark accurately, cut efficiently

Diagonal patterns · 7 min read · updated 5 November 2026 · Written by Tilelico

A straight grid turned by 45°: tiles form diamonds and every edge ends in an angled cut. The pattern catches the eye and hides an out-of-square wall well.

Real example · calculated by Tilelico

Entrance hall of 3.50 × 3.00 m, 45 × 45 cm, 3 mm joint

WholeCutCut under 100 mmStaircase

The grid is centred, but the perimeter and the staircase are all cut at an angle: cut pieces outnumber whole ones, and waste is clearly above a straight lay. A few narrow points are flagged on the plan, worth watching as they break easily.

Calculated result

Room area: 10.50 m²
Area covered: 9.25 m²
Whole pieces: 18
Cut pieces: 52
Actual need: 70
To order (+15%): 81
Waste with no offcut reuse: 34.7 %
Narrow cuts: 4

Most frequent cuts

52 cuts in 14 different sizes.

C01 · 450 × 450 mm× 24
C02 · 207 × 207 mm× 8
C03 · 309 × 309 mm× 5
C04 · 303 × 303 mm× 5

Setting out and products

The grid sits at 45° to the walls: mark that axis from the starting point shown on the plan first, then lay out the 453 × 453 mm repeat along it. Estimated products: 32 kg of adhesive and 1.6 kg of grout.

Reproduce it in Tilelico

1Draw a 3.50 × 3.00 m rectangle, then add in the centre: Staircase.
2Choose the covering: 45 × 45 cm, 3 mm joint.
3Select the “45° diagonal” pattern.
4Set the distribution to “Centring” and the margin to 15%.

Open this example in the editor

When to choose it

It suits small rooms that need energy and rooms whose walls are out of square.

Best forEntrance halls, small rooms and square tiles.
Avoid ifThe budget is tight or the size very large: angled cuts cost material and time.

Continue with: Offset diagonal laying: a lively pattern that takes planning →

Preparing the job

Plan a higher allowance than for a straight lay. Tilelico adds it to its recommendations because every edge is cut.

Check that your cutting tool makes clean angled cuts on the chosen size.

Continue with: Straight tile laying: the complete guide, with a real example →

Step by step

Step 1 — Mark the room axesSnap two perpendicular lines through the middle of the room, checked with 3-4-5.
Step 2 — Mark the diagonalsFrom the crossing, transfer the same distance on each axis: the line joining those points is at 45°.
Step 3 — Dry-layLay out a full row to check that the triangles are large enough at both ends.
Step 4 — Work from centre to edgesProceed one quarter of the room at a time, keeping the diagonals as references.
Step 5 — Cut the trianglesThe cut list groups identical triangles: cut them in batches after checking a first piece.

Continue with: 45° herringbone: the classic French presentation →

Mistakes to avoid

Starting from a wallOn a diagonal, an out-of-square wall soon shifts the whole pattern. The reference remains the axis crossing.
Forgetting fragile pointsA thin point breaks when cut or laid: shift the grid if the plan shows any.

These pointers describe common practice, not imposed rules. The data sheet for your covering and for your installation products always takes precedence, and measurements taken on site are the reference.

Frequently asked questions

What allowance for a diagonal lay?

Common practice is often around 15%, but the need depends on the size and the room. Compare the allowance with the calculated waste.

Does a diagonal make a room look bigger?

It creates lines longer than the walls and breaks up a corridor effect, which often gives that impression.

Technical references

This guide describes common installation practices. It does not replace applicable technical documents, manufacturer instructions or measurements taken on site.