I've got a retaining wall that I had to tear out because it stopped retaining anything (dirt was flowing right through it). It was put in by the original builder of this house, and no gravel backfill was used! The wall was simply erected, and dirt was filled in behind it. That's it.

So I've removed the wall and excavated about 1' behind it. I intend to fill that entire space with washed #57s. I also intend to drop a 4" perforated PVC pipe at the base. The wall is 33" high and about 11' long.

My question is, what should I use to line the back of the wall? Thick plastic? Soil fabric? Roofing felt?

Ryan