On Jun 16, 12:24*pm, Joe wrote:
On Jun 16, 3:16*am, ben wrote:

snip
*So I bought a chalkline but I now realize, I don't know how I can make sure
it's level. *The length will be about 27'.

How can I level this? *Or is there a better way to do this?

I have a small 'line level' that simply hooks into the center of the
chalk line. With one end firmly attached, the other end of the line
can be raised or lowered *incrementally until level. Only takes
minutes, seems perfectly accurate and IIRC it cost about $5 or so at
local lumber yard, hardware store or Ace, maybe. First time I saw one
being used was a siding installation crew. Ought to work for you.

Joe

The trick with a line level is to level the 2 end points over a long
distance, then remove the level and pull the chalkline taut between
the 2 points before snapping.

Over 27' feet, the level is going to bow the line downward
significantly, so the only 2 level points along the line will be at
the very ends.