Garden Wall for 4180 sw 99th

http://wiki.keithl.com/GardenWall rev 0.1 2022 Aug 11

Our neighbor's fence is already in place. There are non-treated boards below the level we had asked for, so we will need to extend our two-stone-tier wall end an additional 4 feet to the west. Or ... we just put some composite deck boards against the bottom fence rail, and fill in our side with dirt. Probably easier for the first 10 feet or so.

There are some large rocks in the ground left over from the previous railroad-tie wall. Those are very heavy and require machine removal. Otto, not Manuel.

Digging beside the fence and placing a wall will require a trench as wide as the digging machine scoop, and we will need a track (how wide?) for the digging machine, which overlaps where our garden currently is. We plan to replant the garden anyway, so track away! We can temporarily screw some plywood on our side of the fence so the machine won't damage it.

A wider wall unit with a hollow center, like the CornerStone 100 flat face block, will be more stable in an earthquake ( read Living with Earthquakes in the Pacific Northwest to learn how lethal they can be in western Oregon ). The Near Vertical Flat Face 100 Unit will make the gap to the fence smaller.

Summit-blend split-face color, so the dirt shows less.

I propose we extend the wall 12 inches above the above the dirt. A 4 inch high "Flat Face 50 Straight Side Cap" on top of that wall, raising it to 16 inches. And on top of that, I will create a sitting bench of composite deck planking, filling in the gap to the fence so that nothing falls down there. That will create a 17 inch high bench for sitting, planters, or tools.

Except ... wasp nests? we probably don't want to leave big hollows. Unsolved problem. Perhaps we fill the gap to the neighbor's wooden fence with packing peanuts and bubble wrap from Too Many Amazon packages.

The flat face block units are 18 inches wide and 8 inches tall (one square foot), so as a wild guess 120 blocks (40 units on 3 pallets) and 25 caps, including breakage and goofs.

To strengthen the wall further, some 4x4 composite lumber poles in the 5 inch holes that thread through and between the interlocking blocks. I considered raising some of those poles up above head height, and hanging planters on crosswires, but that will cause a lot of side torque in an earthquake. Better to use separate posts planted in the garden soil, not the wall.

I hope the garden soil can drain through the bottom tier on the short eastern side of the wall ... somehow. Perhaps extending farther to the east, beyond the current "face", and filled with large crushed rock. If trench is wider than 18 inches, we can lay a perforated plastic pipe (with a permeable sleeve) as a french drain, next to the bottom tier of blocks. I've dug french drains near the road and driveway, and in the back of the house.

French drain gravel from Cedar Mill Landscape Supply, they deliver by the truckload. We may also want to gravel our south side grass driveway, so you and other contractors don't sink in that bog.