Building a Landscape Wall

The information contained in this blog post is for a shorter landscape wall. If you want to build a tall landscape wall, the process will be slightly different. I consider anything five courses or more to be a tall landscape wall. The reason the process is different is that the forces of wind on a tall wall require bracing. You can create bracing with a structural frame, by curving the wall so that it is self supporting, or by adding buttress walls. Buttress walls are short sections of wall that run perpendicular to the main wall. For anything four courses or less, you can use the techniques outlined here.

Foundation Options for a Landscape Wall

The foundation of a landscape wall does not have to be as intense as that of a home. The loads placed on the foundation are just those of the wall itself, including the weight of the plaster. There are no roof loads (unless you add a roof to your design) and no major framing loads; known as dead loads. I have seen foundation systems made of earthbag, stacked stone, and other simple materials. Concrete is the most common foundation material, hands down. Regardless of the material you use, build the foundation the same width as the bales. If you have changes in elevation on your site, step the foundation in intervals equal to a bale height. in other words, if your bales are 14″ tall, make each step in the foundation 14″. This allows you to align the subsequent courses without having to adjust for the foundation steps.

Install Adequate Toe Ups

Be sure to add toe ups to your wall. A simple toe up assembly of a 4×4 on each side of the landscape wall will provide excellent stability for the bales. Toe ups lift the bales off of the concrete and provide a nailing surface for the mesh. You can use a double stack of 2x4s if they are less expensive and more readily available. Lay roofing felt down on top of the concrete to create a capillary barrier between the bales and concrete. Fill the space between the wood members with gravel. This supports the bottom of the bales and provides a further capillary break. Use 20d, hot dipped galvanized nails to secure the bales to the toe ups. As you can see in the photo, they should be nailed in far enough to hold tightly to the toe up, but still need to stick out enough to hold the bales. You’ll drive them into the wood roughly 1″.

Stacking Bales

The bale stacking process is pretty much the same for a landscape wall as it is for a house. Be sure the bales are flush to the edges of the wall and each other. Make sure the bales are stacked plumb. You don’t want them leaning one way or the other. I prefer to keep all of the “cut side” of the bales facing the same direction. Which direction is not important; however, the cut side of a bale and the folded side perform differently when weed-whacking, so it’s best to keep them facing the same way. You’ll need to retie some bales to make them fit. I use the same knot here as I do on my houses: the Miller’s Knot.

Once your bales are stacked, you’ll need to weed-whack them to clean up the sides. This step really helps to give a solid plaster anchor as it removes the loose straw. Some people skip this step, but I find it both satisfying and important. By removing the loose straw the wall will look sexier and will perform better. And who doesn’t want a sexy landscape wall?!?!

Protect the Landscape Wall from Water

The top of the wall needs to be protected from water intrusion. Some folks will build a roof structure that they place the bales around. This is a great option, but it costs more money, takes more time, and uses more materials. Instead, you can simply install a thick pond liner (EPDM rubber membrane) on the top of the bales and hang it over the sides by a few inches. This will direct water away from the top of the bales and let it drain to the sides. The straw can handle water on the sides of the landscape wall. What you want to avoid is water draining down into the middle of the bales.

In truth, if the bales completely rot away in the next fifty years, it won’t really matter. The straw is not acting as insulation. It is basically just a form for the plaster. Of course, I am not suggesting you build with that intention. Build your wall with the goal of it lasting a lifetime (or three). Just know that if your seal is not perfect, the implications are not as dire as if it were your house.

Plaster Lath for the Landscape Wall

Plaster won’t stick to the rubber membrane on the top of the wall. The membrane’s  job is simply to protect the wall from water intrusion. Now you need a way to make your plaster stay put and protect the entire wall from all the elements and pests. I use a plaster-lath cap. Place this over the membrane and use 9″ landscape pins to secure it to the bales. Do your best not to penetrate the membrane. It’s important to create corners that are solid and overlapping with lath. Any lath that doesn’t overlap is likely to cause a structural crack in the plaster. Use a minimum of 1″ overlap. Three inches is better.

Structural Mesh Holds it all in Place

Place 2″ x 2″ welded wire mesh over the top of everything else you’ve installed on the landscape wall. This mesh should be pulled tight and stapled to the toe ups on either side of the wall. Tighten the mesh from both sides at the same time. Pulling one side tight and then the other will make the wall lean to one side. Place even pressure on your tensioning forks so that the wall is pulled straight down. Don’t worry if the wall isn’t perfectly straight at this point. All the pressure of the tensioning might tweak the wall slightly. Use a tamper or a bale persuader to move the wall back into line once all of the mesh is installed.

I use 7/16″ crown x 1-1/2″ staples to secure the mesh. Shoot a staple diagonally across the weld of the mesh every 6″ or so. The mesh should be overlapped by a minimum of 6″ when connecting to the piece next to it. This stops cracks from occurring along that join line. You may find that as you tighten the mesh, the top of the wall gets a slight crown to it. That’s actually great! It will help drain water off of the wall rather than allowing it to sit on a flat wall surface.

Sew the Mesh to the Landscape Wall

The final step is to sew the mesh on an 18″ grid. In other words, place a tie every 18″ both vertically and horizontally. Each tie should be about 9″ long and is sewn on a diagonal to the mesh. this pulls the mesh tight and doesn’t create divots in the  wall in the process. Tie the mesh as tight as you can. You should not be able to get a finger between the stitch and the bales. Use the same baling twine to make each stitch. I use a template to cut all my twine to length before I start sewing. This speeds the process up dramatically. It’s also a lot easier to carry a bunch of pre-measured twine lengths than it is to haul the entire roll of twine around with you.

Ready for Plaster

Voila! That’s it. A few more adjustments of the wall with your tamper or persuader and you are ready for plaster. The landscape wall gets the same three coats of plaster as a house would. I use hydraulic lime plaster as it is durable, strong, flexible, and a natural product. (Be sure to tell the folks at the above link that you heard about them through me and they will give you a discount on your order!) If you use earthen plaster, you would need to provide protection from the elements in the form of a roof structure. It simply cannot handle the constant exposure to the elements the way lime can.

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15 Responses to Building a Landscape Wall

  1. Avatar
    Ken Sun, September 26, 2021 at 9:40 am #

    I love it. What a beautiful example of how to use straw bales in a new way. Thank you for sharing.

  2. Avatar
    JohnLee Sun, September 26, 2021 at 9:58 am #

    A landscape wall isn’t a structure that needs a permit, so there aren’t requirements, but most foundations extend 50% wider than what’s being supported. In some instances it is to distribute the loads which you accurately comment are minimal here, but the wider footing also provides greater stability. You don’t comment on the thickness of the footing but that relates to the material used. All of that and the soil conditions probably get back to your comment on the expected lifespan of the wall, and whether measured in years, decades, or lifetimes.

    I also wondered about the cross ties. Would it be easier to precut them and just place them at the appropriate spacing between bale layers rather than using the needle?

    Good article. Thanks

  3. Avatar
    Barney T. Sun, September 26, 2021 at 3:02 pm #

    Can these landscape walls be used as retaining walls where one side has dirt up against it and the other side open? Its my understanding bale walls should not be buried?

  4. Avatar
    JOY Burton Sun, September 26, 2021 at 5:59 pm #

    From Waddell, Arizona (that’s west of phoenix)….I still want to attend a workshop…even if I am old…and we won’t be building a straw bail house…I love these methods, I am a do-it-yourself person (my husband is not) Thank you for showing us how to build a landscape wall…I might be able to try that on my own…We have 2 and1/2 acres…just no electricity…or home??Thanks for the landscape wall directions..Sincerly Grama Joy

  5. Avatar
    Bob Rover Sun, September 26, 2021 at 9:01 pm #

    Dear Andrew, Here in Las Cruces, New Mexico, a lot of Flat Roof Houses and deck walls are
    capped with stucco. But MOISTURE collects and eventually cracks the stucco and makes for
    expensive repair. Do your plans include a moisture vent ? The walls around here are built
    on framed wood and are hollow on decks or are insulated in the house construction.
    Good bless you. I still want to build a straw bale house someday. Where ????
    Bob Rover, 303-717-4874

  6. Avatar
    sandra Tue, September 28, 2021 at 10:48 am #

    Is there a photo to see the application of palster?

    Thanks

  7. Avatar
    Lillian Gottfriedsen Wed, September 29, 2021 at 12:41 am #

    Hi there,
    I’ve been following your workshops, newsletters etc since 2005 when we built a timber frame straw bale.
    The plaster has been eroded by birds’ nests. as we ran out of time, energy and funds to finish the 3rd coat w/lime.

    Initially, it was going to be concrete and has wire mesh throughout, however we used our own materials and made a mud finish; we applied two coats and ran out of steam. The birds have been having a hayday with their nests and all. My question to you is, can we put cement plaster over the mud? or should we fill the bird holes and put make more mud which means, complete with 3d coat w/lime.
    What is the best way to do this? I’m just tired of looking at it (birds) and want to finish it. What are your thoughts?

  8. Avatar
    Carlos G Torres Wed, September 29, 2021 at 9:38 am #

    I would love to hear more about the landscape straw bale project

  9. Andrew Morrison
    Andrew Morrison Wed, October 13, 2021 at 7:18 am #

    Hi Sandra. Unfortunately, no. The weather was rainy when we plastered the casitas in the project, so we were not able to plaster the landscape wall while I was on site. I am sure the owners have done so by now, but I don’t have photos of it. The process is the same, however, for the landscape wall as for any bale wall. In this case, the owners are using a three coat Natural Hydraulic Lime plaster system.

  10. Andrew Morrison
    Andrew Morrison Thu, October 14, 2021 at 10:23 am #

    Hi Carlos. I don’t have a lot more to share about it, other than it looks great! Let me know if you have specific questions not answered in this post. Cheers.

  11. Andrew Morrison
    Andrew Morrison Thu, October 14, 2021 at 10:24 am #

    Hi Barney. No, I would not recommend that as the straw will rot if buried underground. You would want to use some type of masonry wall below grade and could then transition to bales above ground if the wall covered that much vertical space.

  12. Andrew Morrison
    Andrew Morrison Thu, October 14, 2021 at 10:28 am #

    Hi JohnLee. All good points about the foundation. That said, bale structures are most commonly placed on footers that are equal to the width of the bales. The driving factor is the bearing capacity of the soil. The wider footing under a bale wall exceeds code requirements, so should, especially in the case of a small landscape wall, last a lifetime.

    The problem with placing the ties in the walls as you are building is that you’ll need to weedwhack the walls prior to meshing/plastering. Those ties will all get ripped out of the wall and wrapped around the weedwhacker head. Sewing the walls is an easy task, and doesn’t take much time. We use precut lengths to speed the process even further.

  13. Andrew Morrison
    Andrew Morrison Thu, October 14, 2021 at 4:08 pm #

    Hi Lillian. You are best off finishing the plaster with the same material you have started with: clay plaster. If you do a finish layer of lime or cement, they will most likely delaminate over time as they are more rigid that the coats beneath them: a recipe for failure. I would go with a final coat of earthen plaster, finished with some color to make the house look different than the natural earth around you (the birds most likely think they are nesting in an earthen slope, NOT your house. You can also polish the final coat of plaster to get a tighter finish. I am not an earthen plaster expert, so I am not the right person to ask about those details. I would suggest you contact Athena Steen at the Canelo Project. She is a master of earthen plasters. What I can tell you is that lime over earthen plaster is one of the biggest failures I see in plastering consultations.

  14. Andrew Morrison
    Andrew Morrison Thu, October 14, 2021 at 4:11 pm #

    Hi Bob. We do not have a vent in the landscape wall system. I don’t expect the walls to behave the same as a framed system. Further, even though this sounds terrible, if the bales were to eventually rot out, it wouldn’t matter since they are basically just a form for the plaster. The wire mesh and plaster would do fine on their own if need be. Again, I don’t think this will be an issue based on the pond liner, sloped top, and relatively small amount of direct exposure to water infiltration.

  15. Andrew Morrison
    Andrew Morrison Thu, October 14, 2021 at 4:11 pm #

    You are welcome Grama Joy!!!

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