I had a problem with some PVC conduit in a garage/home workshop a few weeks ago.
I carefully fitted the spacer saddles in line with the brickwork across the end extension and installed the conduit nicely parallel with the joints. When I stood back and looked at it from a distance the conduit (white) was obviously sloping downhill.
The problem was that the brickwork was not horizontal. If I adjusted the conduit with a spirit level to get it dead horizontal, it looked fine from a distance, but up close it looked bad because it didn't line up withe the brickwork.
No way to win on that one!
