Tiling L-shaped & complex rooms

Handling corners, step edges, and irregular shapes

The challenge of non-rectangular rooms

Most real rooms aren't perfect rectangles. Open-plan kitchens, hallways with alcoves, bathrooms with shower recesses — these L-shapes and T-shapes create concave corners where the tile grid meets extra edges. Each extra corner means more cut tiles and more opportunities for the layout to look awkward.

The goal is a continuous tile grid that flows across the entire room, with no visible "seam" at the step edge and no paper-thin slivers at any wall.

How to measure complex shapes

Walk the perimeter of the room and measure each wall segment in order. Start at one corner and move clockwise, recording the direction and length of each segment. An L-shaped room typically has six sides — three horizontal, three vertical.

For example: start at the top-left corner and go 500 cm right, 200 cm down, 200 cm left, 100 cm down, 300 cm left, 300 cm up. These six measurements completely define the shape. Enter them into a layout planner that supports polygon rooms and it will build the floor plan automatically.

The step-edge problem

At a concave corner (the inside corner of the L), a row of tiles that runs past the step edge will be cut on one dimension by one wall and on a different dimension by the perpendicular wall. This creates small corner-cut tiles that are cut in both width and height — often tiny and fragile.

A good layout planner identifies these corner cuts and lets you shift the grid position to minimise them. Sometimes moving the grid by just a few centimetres eliminates an entire row of slivers.

Grid continuity across the room

One common mistake is to treat each "arm" of the L as a separate rectangle and tile them independently. This creates a visible mismatch at the step edge where the grout lines don't align. Instead, the tile grid should span the full bounding box of the room — one continuous pattern clipped to the room shape.

Optimising the grid starting position

In a rectangular room, you choose where to anchor the grid: from a corner, centred, or aligned to a specific wall. In complex rooms, the optimal position needs to consider all walls simultaneously. The goal is to avoid thin cuts (less than one-third of a tile width) at any wall edge.

This is a harder optimisation problem than it sounds. With six or more walls, there are many more constraints. A brute-force approach tests dozens of grid positions and scores each one by the minimum cut size it produces — the position with the largest minimum cut wins.

Ordering tiles for complex rooms

Complex rooms generate more cut waste than rectangles because there are more edges to cut against. A rectangular room might need 5% cutting reserve; an L-shaped room should have 7-10%. Rooms with more than four corners — T-shapes, U-shapes, rooms with alcoves — may need 10-15%.

A detailed cut map that shows every cut tile, its dimensions, and which corner it belongs to helps the tiler plan their cuts in advance and minimise waste by identifying which offcuts can be reused elsewhere.