Garden Wall for 4180 sw 99th

http://wiki.keithl.com/GardenWall rev 0.2 2022 Aug 12

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Our neighbor's new wooden fence is already in place, we will not be building that on top of our block wall, but build the block wall pn the north side of that wood fence, hopefully with the top cap extending near it ... somehow.

Answer one: Wall color: Summit-blend split-face color, so dirt shows less. Most of the wall will be facing the fence, with a top cap, so only the wall that sticks up above garden level will be visible.

Q1: With the wall beside the fence, there will be a "triangular void" that we don't want things (or feet) to fall unto. Perhaps we extend the wall cap to abut that. What can go wrong with that (insect nests? fence rot?), and how do we avoid problems?

The neighbor's fence has un-treated boards below the level that we had asked for, so I faced those west-end bottom boards with some Hardi-board and leveled the dirt to them, so that our walking path is level.

Plan to start the west end of the block wall eastwards a few feet. That slight reduction won't change the volume of the wall or the scope of the work very much. I have more 12 foot lengths of Hardi-board that we can use to "shingle" the lower part of the wooden fence. If equipment breaks one of them, we can quickly fix that.

There are some large rocks in the ground left over from the previous railroad-tie wall. Those are very heavy and will require machine removal. Otto, not Manuel. I don't want those heavy, nonstructural rocks causing mayhem in an earthquake.

Q2: How much can you lift with the digging machine scoop? Will we need another machine or tool or winch to move those rocks?

Digging beside the fence and placing a wall will require a trench as wide as the digging machine scoop.

Q3: How wide is the scoop?

Q4: How wide are the tracks of the digging machine beside the scoop?

We will need a stable 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 plan to temporarily screw some plywood on our side of the new 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, but is more likely to tip with a fast ground displacement.

I much prefer stable and earthquake resistant to a few more inches of garden space.

I propose we extend the wall 12 inches above the garden-level 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 can 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. I hope you have a better idea.

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 boards 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 a trellis on them, but that will cause a lot of side torque in an earthquake. Better to use separate posts planted in our garden soil, not the wall.

Likely Change of Plans 1: Steps on the East Side of the East Garden Wall

Accessing the back of the (past and future) greenhouse requires walking all the way around the east end. If we build steps downwards from the east side garden wall, we can reach the back of the greenhouse faster. What is the best way to build those steps?

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.

Note: I manually dug french drains near the road and driveway, and in the back of the house (and got a hernia injury doing so, never again). I don't want you folks getting hernias either (though I can suggest a surgeon).

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. My guess is you will not need the south driveway, and will access the work area from the north side concrete driveway.

Likely Change of Plans 2: Remove some of all of the rock-sided berm on the north side of our driveway

• ...IF removal will give you more room to bring in your digging machine and other tools.

The path beside the garage is currently covered with woodchips. If gravel (or pavers) makes that more stable for your work and your safety, add gravel to the budget as well. Or, we can pay Cedar Mill Landscape to deliver that, and spread it on the garage-side path before you get here.

Future work

Assuming this works out well for both of us, there are some bigger but easier tasks that need doing. Besides removing that obnoxious berm north of the driveway, I hope to re-sculpt the west (street facing) and south side of the front so that there is room for a sidewalk, a terraced south side with a definite edge for the mower, and a wider curve into the south side grass driveway. I would like to smooth the slope of that grass driveway, perhaps gravel it instead; there are some steep stretches that are difficult to climb when the grass is wet.

Perhaps the biggest job will be removing the trashy wire cage on the east side of the house, then rebuilding the wall and steps from the upper to the lower back yard, on the south and east side of the upper back yard. The shallower slope CornerStone 100 flat face block will be better for that as well, perhaps with a planter terrace halfway up. That is high enough to require county permits, and perhaps an engineering review.

More added here later, if you have questions or I think of something else. I hope we can plan this well, so there are no surprises and you can "hit the ground running".