NY a écrit :
What is the trick for removing some of a vertical column of tiles to replace
them, without having to remove the ones beside them to reveal the peg that
each end tile is hooked onto (or the nail that is fastening it to the
rafter), and then remove the column next to that, and so on ad infinitum?

I've done a bit at home, for myself and I made the tools I though
necessary....

I used some 4mm x 25mm flat strip into which I cut a right angle notch
out the side, to hook onto nails. Hooking that on and pulling/twisting,
released the nails. I later improved on it, by welding on a short
handle at the other end, to make twisting it easier.

When it came to flaunching along the edge, I made up a 3' long guide to
do it with. Two 3' lengths of 30mm angle iron, one facing one way to
sit on the tiles, the other facing towards the operator, to act as the
guide. Simply sit it on the tiles and fill up to the face of the angle,
compact and smooth with a plastering float, leave it a few hours to
set, then slide it along to do the next bit. Leave to long and your
guide will be well stuch! I did it 20 years ago and it's still perfect.