A spirit level is an essential tool for making sure whatever you are constructing or installing is straight and/or level. It can be used for both horizontal and vertical jobs i.e. for posts and walls as well as shelving etc. It is an essential tool which is very easy to use.
A spirit level is usually made from aluminium and is available in a range of standard lengths. I have found it handy to have two levels, one for small jobs (230mm long) and another for the bigger jobs around the house, this one is 600mm long.
Note: A spirit level can also be used a straight edge to check if a piece of timber or other material is not bowed. Do this by placing the spirit level against the surface of whatever you are checking; if there is no space or bulge in-between both ends of the level, i.e. both surfaces are touching, it should be straight. Note: Depending on the length of what you are checking, always use the longest level you can get your hands on, as the reading taken is only as good as the length of the spirit level itself.
How to Use a Spirit Level
Horizontal Surfaces
Place the flat edge of the spirit level on the surface you are checking. There is a bubble inside the glass tube. Watch where the bubble comes to rest.
If the bubble is outside of the two lines, then the surface is not level. If this is the case, the surface needs to be tilted or adjusted until the bubble comes to rest exactly between the two lines in the glass tube. It is then level.
Vertical Surfaces
If you need to check if an upright is vertically straight, the level is used in a similar way. The spirit level has another tube glass tube which is used for this purpose.
Place the edge of the level against the upright and move the upright until the second bubble is exactly in the centre of the two lines on that glass tube. At this point the upright will be vertical. Note: Make sure you check more than just one side of the upright, and then check it again.
Other
When using a spirit level it is important to remember that it is a precision instrument and can become inaccurate if it is treated roughly or accidentally dropped.
Please also see A Quick Guide to Checking if Your Spirit Level is Accurate.
