Mark the two end points of the line you are trying to draw.
How to snap a chalk line for roofing.
If you have a well functioning chalk snap line you can slowly play out the line without using the crank.
Using or snapping off a chalk line is simple.
You can create a straight line over a considerably length without any lasers or high tech equipment when you know how to snap a chalk line properly.
Find the endpoints of your line and drive a nail in at each point.
Then hook one end of the chalk snap line to your beginning point.
Stretch the chalk coated string tightly between the nails.
Hold or secure the chalk line at the end point of the line.
Pull the string loaded with chalk out of the chalk reel.
To pop long chalk lines accurately when flooring or roofing.
Pull straight up from the middle and let the string snap.
You may need a measuring tape to set these points.
Attach the chalk line at the starting point of the line.
Hammer a nail or drive a screw into one of the end points.