Watching DIY shows I am often confused by the terms level and plumb. Aren’t they the very same thing?
I can see where this might be confusing, but the words describe two different situations, and both are important when constructing a home, shed or other structure or when installing a door, window, hanging a picture, etc.
The word “plumb” comes from the Latin word Plumbum, meaning lead. To ensure that any given vertical line was true or plumb, a piece of lead was hung by a string, and all work or measurements were taken from that vertical line.
Level means to be true to a horizontal surface.
These two terms were important to create a starting point in a building project, and all the other measurements or additions could be measured in relation to that 90 degree angle that was formed where a plumb line meets a level surface.
However, today we have modern laser levels or the old standby steel or wooden levels to help ensure that our working surfaces are level. To make sure the walls are plumb, you can use one of the older levels, which have two extra site bubbles or one of the modern laser levels.
When needed, I have sometimes used a pocketknife or some other heavy piece of metal tied to a string to substitute as a plum bob. The old plumb bob is seldom used today in homebuilding and remodeling projects, but it is still an invaluable and cost-efficient tool widely used on larger construction projects.