On Wednesday, May 20, 2015 at 8:54:34 AM UTC-4, wrote:
I see lots of references to installing a perforated pipe French drain system behind retaining walls. Usuallying laying the pipe behind the first course of block.

Usually the block is level so as to make the wall level obviously. Shouldn't the perforated pipe have a downward slope to it? If so, how much? My wall will not be very tall but will be about 40 feet long.

I appreciate any help

yes, buthonestly walls always fail, you far better off reslopping the yard.....

my moms house had a retaing wall, i tore it down and let ivy take over. appearance just so so. cost zero, future maintence zer.

sold the home, the new owner killed the ivy, and built nice wall.

its falling over and will need rebuilt.

if he had left the ivy he wouldnt need to do a thing.

i tore out most of my retaing walls here, and only rebuilt ones i had no choice but to keep.

those are showing their age, and will need rebuilt again. y bad knee means it wouldnt be me......