
I am often asked how many tiles are required for the job.
So. . . how do I work out how many square metres are required?
Here's a little tip to start with: You don't need to be super accurate with your measurements. If the height is 2.37m, call it 2.4m. If the width is 1.75m, call it 1.8m. It makes things easier and won't make a huge amount of difference.
Remember - most suppliers of tiles will be happy to take back whole boxes of tiles and give you a refund. Some places will even take back single tiles.
It is ALWAYS better to have too many tiles than not enough.
Two reasons for this . . .
1. If the tiles are coloured they will have a batch number and any decent tile shop will make sure that all the boxes have the same one. (If they don't - check it yourself) The reason for this is because even if tiles are supposed to be the same colour you can be quite surprised by the difference when you put two different batch number side by side. Not always, but it does happen.
2. There is nothing worse than your installer saying he doesn't have enough tiles and when you go to get them you are are told it will be two weeks before the next delivery.
You will not be happy. Your installer will not be happy. Remember, he has allowed a certain time slot to complete your work. If he's got to arrange to break off from another job in two weeks time to come back and finish your tiling . . well . . . think of him too.
One more thing that occurs to me. If you live in an old house or a house where the walls are not very flat please remember that very large tiles may appeal to you but you may be facing an extra cost with wall preparation to use them. Large tiles need good flat walls. Houses with old lime plaster or uneven walls may need to have all the old plaster removed and the walls dry lined with plasterboard to make them suitable for tiling.
Right . . . First of all draw yourself a little plan of the room.

Now to the measuring . . .
A WALL WITH A WINDOW IN IT.
1. I always say by the time you've worked out how many tiles will be needed for the window reveal you might as well just ignore the window.
Imagine the reveal folded out. Will it be much the same as the window itself? Then, as I say, ignore the window.
Of course if it's an exceptionally large window then you should work out the area of the reveal but how many people have large windows in their bathroom?
2. I know it's obvious - but - measure the wall and use metres not feet and inches!
3. Measure the height to the ceiling if there is no cove or you want the cove taken off. Measure to the cove if it's staying.
4. Measure the width.
5. Get your calculator out (or write it down and do it the hard way!) and multiply the width by the height.
6. Write the result down by the corresponding wall on your plan.
THE WALL ABOVE THE BATH.
Generally, unless it's a free-standing bath the wall behind the bath is not tiled so you don't need to allow for that.
Again, quite easy. Width of the wall x height from the top of the bath to the ceiling. Multiply it. Write it down.
NOTE: If you are having a shower tray installed in place of the bath remember to measure from the floor to the ceiling because the wall will need to be fully tiled.
THE WALL WITH THE DOOR IN IT.
Very often it's the same size as the wall opposite so just take that measurement and deduct the size of the door. It will usually be about 2m high x 0.8m wide (1.6sqm).
WALLS WITH SLOPING CEILINGS.

With reference to the following diagrams.

Measure A (X x Y) and B (X x Y) and write them down.

Now measure C (X x Y) and write that down.
If the opposite wall is the same size you can now simply work out the area for the total of both walls at the same time:
((2 x A) + (2 x B)) + C
I know that might be confusing but just think about what you're doing with the area marked C. To work out that area on just one wall you would need to halve your original measurement. Why bother - you've already worked out the same area on the other wall! Imagine the bit that's shown coloured grey (C1) being put on the other wall . . . There it is!
I hope you're following this!
If you're having units installed you may want tiling behind them. Discuss this during the initial quotation. Note that if the units are wall hung, rather than standard base units sitting on the floor, it is probably better to tile the walls first.
Most times it is not necessary to tile behind standard floor standing units because you will never see the wall anyway and most units have backs to them. If this is the case you can deduct some tiles from the totals.
Just measure the width that the units will cover and assume the height to be 0.8m (the normal height of base units) and again, multiply the two figures to get the square metreage, then deduct it from your total.
When you've worked out all the measurement add them all together.
Now ADD 10%. This is important. Tiles have to be cut so there will be wastage which is unavoidable. You HAVE to allow for this. Remember what I said - Better to have too many tiles than not enough.
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Lets just have an example:
Window wall 2.3 x 2.4 = 5.52 - base cabinets 0.7 x 1.7 = 1.19 Total = 4.33
Opposite wall 2.3 x 2.4 = 5.52 - doorway 0.8 x 2.0 = 1.6 Total = 3.92
Side Wall 1 2.3 x 1.8 = 4.14 - bath 0.5 x 1.8 = 0.9 Total = 3.24
Side Wall 2 2.3 x 1.8 = 4.14 Total = 4.14
_____
Sub Total = 15.63
10% = 1.563
_____
Grand Total = 17.19
So I would suggest ordering 18 square metres of tiles.
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If you are going to have a few randomly placed patterned tiles don't overdo it. Less is better.
If you're going to have a border around the room just measure all the way around. Don't forget to add 10% to this measurement too.
All the above can be applied to measuring for the floor tiles too. Width x depth + 10%, then round it up.
A couple more thing worth bearing in mind.
1.The larger the tiles, the more waste there will be so if you are going for a big tile it may well be worth ordering extra tiles.
2. Remember that if your walls are uneven large tiles will be difficult to fit due to the irregularities of the surface and you may find yourself paying extra to have the walls dry lined or replastered - it may be better to have a slightly smaller tile instead!
I hope this has been of some help. If you're not certain check with your installer. Please don't shout at me - this is only intended as a guide!