Originally Posted by
Wildwood
+1 on the @
Road Fan technique, but i use a yard stick instead of a book, the long extention between my legs (ooopps...
) lets me make sure the measurement is taken perpendicular to the vertical. No assistant needed
.
The book, if placed flat against the wall, ensures that the measuring device is horizontal. A yard stick can be inadvertently tilted upwards or downwards.