"Priscilla McCullough" writes:

I am hoping to re-do the pond over when fall hits and go bigger. I have a
couple Koi in my pond a guy gave me and they would be happier in a bigger
pond. Mine right now is 5x10 or 11 can't remember and 3 feet deep. I am
wanting to go 12x18 and 3ft on my side and 3 1/2 on the other.

Deeper. As deep as you can manage to dig it.

Either square
shape or kidney. How much liner do I need for this. I am also seriously
thinking about trying the roofing liner since I am on a budget and pond
liner is so expensive. Seems like you all have had no problems with the
roofing liner.

Sounds that way. I'd probably scrub with dish soap and rinse like mad
anyway :-)