S
Sombrero
if you mark on a board with a pencil cut out half the pencil mark
mark against a surface leave the line in or take it all out dependant off inner or outer edge
in an enclosed area[between walls] measure from one wall to a easy to remember point[1m or 2m for example] and mark then measure from the other side to the mark and add together
if you are doing repetitive marking mark the tape and transfer that mark
Again, that's what this site site is to the DIYer... helping them (like me) see the bleeding obvious, brilliant !!!
Thank you Big all !