Basic Setting-Out and Levelling

KEY POINTS ABOUT SETTING-OUT

Setting-out is the most important process that is undertaken prior to construction work starting. It involves establishing, among other things, the position of the structure on the site, the relative position of walls and all associated levels. The accuracy of horizontal and vertical dimensions is critical if work is to be completed correctly and to acceptable standards.

Mistakes made at any stage during the construction process can be costly to rectify but mistakes made at the setting-out stage can be particularly disastrous. A wrong measurement or wrong angle or being out of square at the setting-out stage can result in large sections of work having to be demolished and rebuilt at great expense.

The basic elements of the setting-out process involve setting-out straight lines in relation to base lines (for example, an existing structure); setting-out 90-degree angles; and methods of transferring levels. The explanations given here are based on a small rectangular building; the basic principles involved can be applied equally to a simpler project such as a straight, free-standing wall, or to a more complex project such as a large building of more complicated shape and layout.