Why does a staggered/brickwork pattern of wall tiles need a particularly flat wall, where a straight pattern is more forgiving? Have heard this a few times and not sure why.
If all the grout lines are aligned, then the complete colum/row 'wraps' to the wall. The adjoining edges of the tile will still be flat(ish) with each other. When doing a running bond( brick bond) and lets say your wall was very convex, your first row would 'wrap' to the curve. When you put your next row on, the horizontal edges of the tile won't be flat to the vertical edge of the adjacent tiles as its 'turning' on a different part of the curve. It can look awful but even with flat walls, certain tiles (usually large format) shouldn't be laid with a running bond as they're warped straight out of the box and will give a similar effect.
That makes sense, thanks. Would a smaller offset reduce this problem, say a 15%-25% overlap rather than 50%, like this: http://www.clayhausceramics.com/images/shapeslb/rectangle_1x4_offset.png
It can help. The other thing is to level the wall(various products to help with this) or use a slightly deeper notch trowel to give you more adjustment. What is it exactly you're tiling?
Blimey, what a thread. A question about something that would never cross my mind and I haven't a scooby about - followed immediately by a clear and concise answer by someone who obviously knows what they are talking about. Perhaps I should point out that this is a SF forum - we don't do that sort of thing on here...