How to plan your wall and floor tiling | Tiling | How to guides | diy advice | B&Q

How to plan your wall and floor tiling

Plan your wall and floor tiling

Successful tiling relies on planning.

To achieve a symmetrical design you must centre the pattern, with cut tiles of equal size at the end of the rows.

Tools and materials

Spirit level

Quantity: 1

Pipe / Power detector

Quantity: 1


Quantity: 1

Tile adhesive

Quantity: 1

Tile spacers

Quantity: 1

Tiling kit

Quantity: 1

Silicone sealant

Quantity: 1

Wall tiles

Quantity: 1

Floor tiles

Quantity: 1

  • Gauge rod
    Quantity: 1
  • Pencil
    Quantity: 1

Tile calculator.
Use this handy calculator to help you estimate the number of tiles you'll need for the job.

Useful videos

Ideal for the job

Detecting hazards
Never drill blind into a wall or floor – you might hit gas or water pipes or electrical wires. A batteryoperated pipe and power detector is inexpensive and essential for making sure it is safe to drill.

A good-quality spirit level, designed to show you a true horizontal or vertical, is a must-have tool when lining up tiles. Spirit levels come in all lengths and prices.

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A gauge rod allows you to work out the positioning of the rows and the size of any cut tiles. Use a 50mm x 25mm wooden batten and make it 1.8m long for tiling a wall, shorter for a small area.

Simply follow these steps to plan your floor tiles...

Preparing the existing floor

  • Concrete - clean with detergent mixed with water and if it is uneven, level it; then lay tiles directly on the floor.
  • Timber - must be strengthened with 13mm-thick exterior grade plywood fixed with countersunk 25mm screws (4mm gauge) or ring-shanked nails at 300mm intervals.
  • Tiles - new tiles can be laid over old vinyl tiles after coating the old tiles with primer.

Calculating quantities

Tiles are sold in packs and the size and number of tiles they contain will determine the area of floor they will cover. When you calculate the area of your floor, remember to include the dimensions of any alcove or bay. Round up the total to the nearest whole number to establish the number of packs of tiles you need. Always buy 10% more tiles than you need to allow for breakages.

1 Lay out a line of tiles with tile spacers between them. Place the batten alongside, lining up the end with the edge of the first tile.

2 Mark the positions of the tiles and gaps on the rod to give you a quick means of working out how many tiles you will need in each row.

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Getting started

Starting out

The first tile, the 'key' tile, determines the position of all the others, so it is very important that this tile is in the right place. Because rooms are seldom completely square, and the walls may not be straight, you cannot start by laying tiles right up against one wall and working your way out from there - you would end up with an untidy mess. The best way to ensure you have a symmetrical design is to start from the centre of the room and work out to the walls in each direction.

Finding the centre of the room

1 First measure one wall, calculate its midpoint and mark this on the floor. Repeat with the opposite wall. With a helper, stretch a chalk line between the two marks and snap a line across the floor. Calculate and mark the mid-point of this line. Tie about 1m of string to a pencil, and while your helper holds the end of the string firmly on the mid-point of the line, pull it taught and scribe an arc on the line either side.

2 Now get your helper to hold the end of the string on the point that one arc intersects the line, and with the string pulled taught draw arcs at a roughly 45 degree angle either side of the centre line. When you repeat this from the other side, the arcs should intersect.

3 Stretch a chalk line between these intersecting arcs and snap a line across the floor. You now have two lines intersecting at a perfect right angle in the centre of the room.

Positioning the key tile

Having found the centre of the room, start at one of the centre lines, dry-lay a row of tiles from the line to the wall. When you reach the wall, make sure that you are not left with a narrow gap because a very thin strip of tile at the skirting will look very odd and may not stick very well. If necessary, move the line away from this wall the width of half a tile to create a larger gap. Repeat the dry-laying from this centre line in the opposite direction and then in both directions perpendicular to it. Adjust the key tile position as shown right, until there is an equal gap of about half a tile at all the edges of the room.

Tiling awkwardly shaped rooms

If the dimensions of the room are irregular, the chalk lines will need to be snapped from a different place - the first line centred on a strong focal point such as a fireplace or patio doors. The room will still be divided into sections but they will be different from one another.

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Vertical rows

The first job is to establish the position of the vertical rows. This will allow you to find the starting point, which should be near the centre of the area to be tiled. Measure the width of the area and mark its centre-point with a pencil.

1 Hold your gauge rod so that one of its marks aligns with the centre-point on the wall. Step off the tile positions across the wall.

2 When you reach a corner, you will see if you need to cut the last tile in the row to fit. If this will be less than half a tile wide, it is best to reposition the starting point.

3 Reposition by aligning the rod with the centre-point as before, then pencil a new mark on the wall so that it falls halfway between two tile marks on the rod. This will be the actual starting position for tiling.

4 Hold the gauge rod against the new wall mark, using a spirit level to ensure that it is truly vertical, and draw a line in pencil from top to bottom.

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Horizontal rows

Having established the positions of the vertical rows, you can check where the horizontal rows will fall.

1 Position the gauge rod against the vertical pencil line, with its end touching the floor (or skirting). Put a pencil mark in line with the top tile mark on the rod. Now move the rod up the wall until it touches the ceiling. If you are lucky, the pencil mark on the wall will align with one of the marks on the rod. If there is no alignment, look at the mark on the rod below the wall mark; halving the distance between them will give you the size of the cut tiles required. It is best if these are at least half a tile deep. If they will be narrower than this, make a mark on the wall in line with the next mark down on the rod.

2 Measure the distance between the two marks and make a third mark halfway between them. Hold your gauge rod just clear of the skirting or floor and move it until one of its marks aligns with the third mark. Make another mark on the wall, level with the foot of the rod. This will be the starting point for the first horizontal row of whole tiles. Draw a level line across the wall at this point. Nail a batten with its top edge aligned with the line. Nail on another aligned to the vertical line.

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Part-tiled walls

When part-tiling a wall, set out the horizontal tile rows so that the top row consists of whole tiles; this will look much better. Mark the position of the top row on the wall and use the gauge rod to determine the position of the lowest horizontal row. Fill the gap between this and the skirting with cut tiles. Move the top row up or down so that you don’t have to cut narrow slivers of tile. You may even be able to avoid cutting tiles altogether, although if the skirting is uneven, some trimming will be necessary. In this case, you will need to start from the lowest point of the skirting. Find this by holding a long straight batten along it, levelled with the aid of a spirit level.

Tiling over tiles

Rather than remove old ceramic tiles, you can simply tile over them. Check that they are all firmly fixed in place, and reglue any that are loose. Make sure that the joint lines of the new tiles do not lie directly over those of the old.

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