I don't normally install retaining walls, but one of my clients keeps adding things on to what he wants me to do. What started out as a simple drainage project turned into bed construction and plant installation, and then expanded to the whole property. Anyway, he wants me to install a retaining wall. It looks like he wants to use Belgard Celtik wall, though his wife may choose something else. The total width is approximately 40', with the lowest part of the slope at the corner of the house. The total vertical rise from ground level to an imaginary level line from the corner of the house is 26". What I'm considering is installing two short walls, one behind the other, and plants in between, to make it appear less obtrusive. I estimate there will be at least three feet between the walls. My questions (keep in mind I have only installed five walls): · Are two short walls worthwhile? The customer is willing to pay, and will do whatever I recommend. His neighbor has a four-foot tall Keystone wall at the corner of his house, and I want to ensure my client's looks better. · What is a recommended method of excavating for the base installation? My previous work has been with Bobcats, because I could (these were construction zones). This is in an existing yard, and I need to dig, not cut away. I was thinking of a mini excavator, though hand digging with my three-man crew is another option (I prefer a speedy method, if it can be cost effective). · If I did install two short walls, are there any special considerations with the second wall? How deep should the base be? Are the drainage issues as critical? I planned to install a socked perforated drain tile at the base of each wall, with stone on top. Is this overkill?