I'm hoping someone can offer some expertise as I plow through this project. I'm installing a 10 x 12 brick patio. I inherited 500 old brick pavers with the house that must have come out of some sidewalk somewhere. They are nice bricks. Note that there are brick walkways in other parts of the yard that I am trying to match - same pavers. The walkways are retained with 6"x6" pressure treated. Also please note that I am aware that the lumber is actually 5 1/2"x5 1/2". All figures below account for that fact. I am installing the patio in an area with a fair grade. Here is my plan (which is now partially executed). 1. Excavate to depth needed for the base layer, sand layer, and 6"x6" landscape lumber. The excavation is done. So at one end the depth is 10" to accommodate 4" of base layer + 6" of lumber. The sand layer will sit inside of the 6"x6". The far end of the patio now sits 20 1/2" below grade. 2. Install patio base stone @ 4" compacted. I am preparing to do this over the weekend. 3. Install 6 x 6 landscape lumber border. 4. Install sand base layer at 1 1/2" compact (does it need to be 2"?). 5. To deal with the grade I plan to step up the border with additional 6 x 6 lumber to create a small retainer on two sides and 1/4 of the third side in order to bring it up to the 18" grade. This will require the addition of two steps running the width of the patio. There will only be one true step as the second step will be at grade. The true step will be 6" x 15" with brick in between. I will back fill the mini retaining wall with landscape fabric and gravel so that any water drains downwards. So my questions: A. What issues could I face with a three tiered mini retaining wall made from 6 x 6 landscape lumber? Does it need a footing of any sort? Weep holes? Note that one of the tiers will be at grade so only two will show above grade. B. What about water under the patio? Because this is built into a moderate slope water will flow behind the retaining wall and under the patio. Please note that this patio is 1 foot diagonal from the corner of the house - close enough that the potential for water in the basement concerns me. I installed a drywell nearby and I could run a french drain underneath the patio if needed, though I would prefer not. C. Do I need to be concerned with heaving in the winter? I'm in Massachusetts so it gets plenty cold. Any advice appreciated!