Why your smallest cut matters
Tile layout is not area divided by tile area. Two rooms can need a similar number of boxes and produce very different floors. The difference is where the repeating tile-and-joint lattice meets each wall. If that meeting point leaves a 10 or 20 mm strip, the piece is hard to hold, hard to cut without breaking, and conspicuous, because the joint runs close to the wall for the full length of the room. Tilers call that strip a sliver.
Starting from the room centre does not automatically solve it. Centring balances one row in a straight grid, but a half-bond or third-bond pattern has several row positions. A centre line that gives generous cuts on one row can leave a narrow return on the next — with the default room on this page, centring is actually the worst of the three. Cutfall evaluates the complete two-dimensional pattern and scores each candidate start by its worst perimeter cut. That is deliberately stricter than maximising the number of full tiles: a layout can contain many full tiles and still finish with a fragile strip.
A worked example — the default room
The floor drawn above is 3200 × 4600 mm, laid with 600 × 300 mm tiles and a 3 mm joint in half bond. Start tight in the corner and the narrowest perimeter piece is 55 mm. Shift the first tile to 546 mm across and 180 mm up and every edge cut becomes at least177 mm — a 122 mm improvement, for no extra tiles and no extra work. Switch the control under the drawing betweenAt the wall and Balanced to see both, and watch the cut detail change to show a piece with the smallest cut.
How to use the plan on site
For a full set-out walkthrough, including the worked arithmetic and transfer to chalk lines, readwhere to start setting out a tiled floor.
- Measure the finished room at floor level in more than one place. Use the shortest dependable width and length if the walls are not parallel.
- Measure an actual tile. A box marked 600 × 300 mm may hold a tile that is slightly smaller.
- Enter the intended joint and pattern. The joint is part of every pitch, so changing it can move a cut or change the number of pieces.
- Read the two start points against each other. The crosshair on the drawing marks the calculated lattice origin.
- Print the plan, then dry-lay at least one row and verify the set-out against the real walls before mixing adhesive.
Limits you should know before relying on it
Version 1 handles one tile size in a rectangular floor. It does not yet model L-shaped rooms, columns, islands, door recesses, falls to drains, or herringbone. Adhesive and grout quantities are planning estimates; coverage varies with trowel, substrate, tile thickness and product. The allowance is applied to the number of drawn pieces and rounded up to complete boxes. Always compare the plan with the product data sheet and conditions on site.
Tile layout questions
Where should I start tiling a floor?
Start from set-out lines that produce usable cuts on every perimeter, not automatically from a wall or corner. The suggested origin is the offset of the tile lattice; transfer it with two square reference lines and verify them by dry-laying.
How much extra tile should I allow?
Ten percent is a common starting allowance for a simple rectangular room, but diagonal patterns, fragile material, colour variation and future repair stock can justify more. The drawing shows actual pieces; the allowance only affects the purchase total.
Why does joint width change the tile count?
Every joint adds to the pitch. Ten 300 mm tiles with nine 3 mm internal joints span 3027 mm, not 3000 mm. Ignoring the joints moves every later grout line and can change the last cut.
What is a sliver cut?
Here, a sliver is an edge piece narrower than the lesser of one-third of the tile’s short side or 50 mm. Anything below 15 mm is marked separately as not practically cuttable.
Does large-format tile change the pattern choice?
It can. Many long tiles have limits on running-bond offset, because curvature can create lippage where a high point meets a low one. Check the manufacturer’s permitted offset before choosing half bond.
Can I use this for wall tile?
You can explore a rectangular elevation, but the output is written for floors and does not account for a bath, ceiling, niche, trim profile or required full tiles at exposed shower edges.