Rotary laser levels

dom · 2006-08-18T15:47:34+00:00

The problem: Inside a building 9m by 12m, I need to mark horizontallines around the walls at heights of 3.2m, 3.8m and 4.4m above floorlevel (assume the existing ground floor is none too level, so I willpick a datum point).I'm assuming a rotary level is the best tool for the job. I was taught(donkeys years ago) to use a theodolite and surveyors level - so I'massuming using the modern kit is the same big boys geometry?Looking in screwfix, there's the cheapy stuff (I'd buy one) or there'sthe professional stuff (I'd probably hire it).Is the difference one of durability? Usability? Acuuracy? Are thecheapies in fact near-useless crap for any serious task?Is the best solution to mark a level baseline on the wall near groundlevel and then measure up from there at points all around the walls? Orwould I be better trying to set the instrument up on a high masonryledge ? (there's one at slightly more than 3.2m from the ground). Thatinvolves more faffing to set it up, but less error over verticaldistances (and less object in the laser path to work around) - is itlikely to make a scrap of difference anyway?I'm going to be basing alotof work around this bit of marking out - soI'm willing to go to some trouble to get the most accurate results Ican get.