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I am wondering if the following would be structurally reasonable for a garden privacy wall, setting aside any local zoning ordinance issues. Three 12" diameter 4000psi tube-formed footings with a 12" high by 16" wide 4000psi concrete pier resting on them, and a masonry wall on that. The wall would be a privacy screen and would not be supporting anything.

Specifically: is a strong mortar bond between the horizontal concrete pier and the brick enough to prevent a wall of that height from toppling, assuming the freeze-thaw issues are dealt with properly, the brick is properly laid, plumb and square, and the only worries are a person leaning their weight against the wall or stumbling so that there's a little impetus in addition to their weight?

P.S. There is also a variation with a much less heavy knee wall that would have wooden-trellis mounted atop the wall cap; the horizonal "beam" or "plinth" sitting on the tube piers would be 4000psi concrete properly reinforced with 1/2" steel rebar.

patio knee wall on tube footings

Here is the full "folly" version:

masonry privacy wall atop tube footings

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  • What's stabilizing the wall laterally? Will you leave rebar protruding from the piers? What sort of footings are under the piers?
    – isherwood
    Sep 29, 2023 at 14:10
  • We are constrained for space: the structure cannot be any closer than 10 feet from the property line and so there's not enough "legal space" for buttresses on the exterior face of the wall. They would have to be placed on the interior side, and so they would have to be placed at the outer edges, otherwise they'd really interfere with the usable space "inside".
    – mr blint
    Sep 29, 2023 at 14:19
  • I can leave the rebar protruding from the top of the tubes to prevent any lateral movement of the horizontal concrete pier. The tubes would go down about 36" inches and rest on undistrubed soil. There's not enough space for the preformed tubes that are like chess pieces with a wider-circumference base.
    – mr blint
    Sep 29, 2023 at 14:33
  • 2
    Masonry means heavy stuff that really hurts your feet if it falls down. Non structural usually means something weak. The two together usually not good. Does it need to be masonry?
    – crip659
    Sep 29, 2023 at 14:33
  • No, it doesn't have to be masonry. That's just one idea we're looking at. Could also be some sort of wooden structure with a trellis, which would be within my abilities to construct. A wrought iron trellis would look cool but when I priced that out from a local metal shop, it would be very much over the available budget. I can weld but I don't have any way (or place) to set up fixtures for something that large. With respect to "non-structural", I meant that it wasn't supporting anything. It would be like the monolith in 2001: A Space Odyssey, except with windows :-)
    – mr blint
    Sep 29, 2023 at 14:37

2 Answers 2

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The only good reason to do a masonry wall is that you either (1) have free materials (field stones, used bricks, etc.), (2) that you need something with very good compressive strength (e.g. foundation), or (3) fireproof (e.g. chimney.) None of these apply to you.

Your design does now show how you will counter lateral forces, e.g. someone just pushing the wall. Falling masonry is not just an annoyance, but can kill.

If you can dig holes for sonotubes, you might as well dig a trench and let this very heavy wall press against even soil.

If you want masonry because of the looks, just build a wood frame and use a brick veneer. But otherwise, there are a million alternative for privacy walls, including live hedges, wood, plastic, metal, etc.

I saw your comments about a wood fence being too expensive. I don't know where you live, but I can't imagine a scenario where a masonry wall would be less expensive than wood, unless you are getting the bricks for free and your labor is worth nothing.

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  • The wall has to be 7' tall because our lot is one in from the corner, and the corner house faces the intersecting street, so our houses are perpendicular to each other. Their 2nd-storey windows look directly down onto our patio. There's only 20' of distance between the houses (10 foot setback). We're considering alternatives. Live hedge would take too long to get tall enough. Trellis with vines is probably what our live growth solution would be. It was a high quality wooden beam solution like a gazebo kit that would be a lot more expensive, since I do have a deal on some brick.
    – mr blint
    Sep 29, 2023 at 16:30
  • A tall fence is an option. It is allowed since it would be set back 10 feet from the property line.
    – mr blint
    Sep 29, 2023 at 16:31
  • If you need a tall fence, even more reasons not do use bricks.
    – Cheery
    Sep 29, 2023 at 16:43
  • A low wall (3 ft or less) and a fence on top of it could look good.
    – mr blint
    Sep 29, 2023 at 16:53
  • Re: "Falling masonry is not just an annoyance, but can kill", see this tragic story from a few years ago in Cleveland. Sep 29, 2023 at 20:32
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For lateral stability of a 7 ft tall wall, you would probably opt for a bit of perpendicular wall. By the time you're done, that ornamental metal work is going to sound very cheap.

If you're in a hurry to get that privacy, then many people opt for thin lattice, either wood or plastic. If you go that route with the intention of growing something on it, I suggest something that doesn't twine around supports like many vines do. Those twiners destroy lattice. I would use a climbing rose, where you don't weave it into the lattice; you periodically tie the canes to the lattice's face.

If you've got some garden space transverse to your wall, clumping bamboo can fit in a 4 ft thick row and will grow to 7 ft in about 4 years if you use 1' to 2' tall starters. Clumping bamboo tends to max out around 10 feet of height and doesn't spread crazy like many people expect. Technically it could work in a zone 5, but zone 6 and above is more appropriate.

In between the lattice's 0 years and the clumping bamboo's 4 years, you can grow vines (or climbing roses or whatever) on a trellis to get that privacy in 2 or 3 years. For aesthetically pleasing and cheap I use round, treated fence posts from a local place in the PNW called North40, where 18 USD gets you a 4"x10' post (I like the aesthetic of using warped posts to give the trellis some out-of-plane interest). Poultry staples are hot dip galvanized to resist wood preservative and weather, where they're great for attaching galvanized wire for the trellis's horizontal lines, although I've also "Molly Hoganed" (https://www.youtube.com/watch?v=AhLR2nexWH0) galvanized wire rope to the poultry staples (anything to save a buck) for sagging horizontal lines.

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  • Thanks for the suggestions on tying rather than weaving with the lattice. With respect to bamboo, that would get me run out of town on a rail if my neighbor didn't kill me first. It's not allowed under local ordinances and she was largely responsible for that ordinance. As for the wooden posts, that was high on the list, but locally, I cannot find long posts that have been treated in an environmentally friendly manner (e.g. acetylated like Accoya or silicated like TimberSil).
    – mr blint
    Oct 2, 2023 at 13:52
  • Though I've read some reports that TimberSil doesn't live up to its claims.
    – mr blint
    Oct 2, 2023 at 14:13
  • @mr blind, the copper preservatives commonly used are perfectly safe. The dosage rates on the arsenic ones even made those pretty safe. You might open a question on the subject of lumber preservative to get references.
    – popham
    Oct 2, 2023 at 15:44
  • @mr blind, you should look into the difference between "clumping bamboo" and "running bamboo." The rhizomes of clumping bamboo have an upward turning habit where it takes about 10 years for the diameter of a clump to reach 5 feet in diameter. Typically you'll divide it and move divisions along your barrier line to accelerate filling the gaps between plants.
    – popham
    Oct 2, 2023 at 15:49
  • I will look into clumping bamboo, but I suspect they won't allow it. The local regulations forbid "Any monopodial (running) woody grass from the genera of bamboos including, but not limited to, Bambusa, Phyllostachys and Pseudosasa, as well as common bamboo, golden bamboo and arrow bamboo".
    – mr blint
    Oct 3, 2023 at 14:01

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