Tightening Bale Ends in the Wall – StrawBale.com

Written by Andrew Morrison

One situation you are likely to find yourself in when building a straw bale house is the ends of bales sticking too far into a room or beyond the plumb line of an exterior wall. As you know, when you build a bale house, you interlock the corners by placing one bale East-West and then the next bale course North-South as you turn the corner. In doing so, it is easy to stack one of those bales out of plumb and not notice it until the whole wall is stacked.

Another place this is common is around window and door openings. I have seen many folks terminate the bales too far into the window opening to create the shape they want when meshing and shaping. Those bales need to be cut back to allow for proper shaping. Here we cover the topic of tightening bale ends in the wall.

Exactly how to fix this problem can impact the quality of your walls and the ability of those walls to anchor mesh properly when you shape corners, etc… In the past, the simplest fix was to cut the twine on the bales that were out of plumb and pull out the excess stuffing to get them back in line. This works well because the bales, once stacked tightly to the ceiling, can handle the cut twine without falling apart.

The problem comes during the shaping/meshing portion of the build. When you stretch the mesh back across the bales and then landscape pin it, you are asking the bale to hold the pin; however, you are also asking the mesh to hold the bale since you cut the twine thus limiting the strength of that bale. Therefore, both cannot happen. The bale cannot hold the mesh because it will be too weak from losing the twine and the mesh cannot hold the bale without an anchor point for the pins. Oh what to do? 🙂

turning wire fencingThe answer comes from an old farm fencing trick. Have you ever looked at barbed wire fencing on an old farm? If you check out the last section, at the corners, you will often see a rotting old stick wound up in the wire. That stick is the answer. It is called an apron tie. The stick is used to twist the wire tight and then is left in place to hold the fence tight. This same concept works with bale ends.

I use a bale hook to scrape away some of the straw on the ends and then pull out the rest of what I need out by hand. Then using either a stick, a piece of rebar or bamboo, or a nail, I twist the baling twine tight with the apron tie. A 20d nail works well because once it is twisted tight, you can stick the nail into the bale to hold it in place. The larger items like rebar and sticks are a bit stronger and often easier to twist, but require additional anchoring to hold them in place. If you use the larger twists then use a landscape pin to hold the tie in place.

This concept will provide really strong bales to attach the mesh to and will easily clean up those “growing corners” as I like to call them. Of course, keeping your corners plumb and in check from the start is always the best plan, but it is good to know you can fix them if they are not set up properly.

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5 Responses

  1. We found a way to prevent this “bulge at the corner” problem was to lay the corners of each course first, and then fill in the flemish bond to the middle of the length of the row. As we got close to the middle, we would select the last two or three bales from the short, medium or long pile to ensure a comfortable fit without squeezing. We used to make the three stacks as the bale came off the truck; our bales varied from 825 to 1050mms long. This saved the work of half or quarter bale preparation, the most time consuming task. As long as the bale joins on each row were offset from those above and below, where they occurred is not an issue, as they will be covered with stucco in due course. The key is NOT to squeeze the bales in – those pressure will gradually result in a bulge or curve in the wall, or this bulge at the end problem.

  2. Thanks Warwick. The problems I have with this concept are that if you start in opposing corners and build towards the middle, then the middle of the wall will always be a weak point because the bales will not be fully locked together. In other words, it will be somewhat of a solid line up the middle of the wall where the two ends meet.

    Secondly, the pressure that’s created by making the bales fit tightly works really well to shore up the walls and create really good backing for the plaster. If the bales are placed gently in the wall, it won’t be as strong without taking additional steps to tightening things up. In the homes where I’ve used this tightening technique for the “bulging bales” I’ve only had 1 or 2 bales that actually needed it. That’s minimal work for a strong wall.

    If I’m missing something in my assumptions here, I’d love to hear more about how you do things. I’m always open to learning new techniques!

  3. Somewhat related question. I built a two story jumbo bale load bearing house. The plan is to finish the roof and pack it for winter, but there’s a rather big worry. All walls seem to be nice and straight except for one section of the ground floor wall bulging outwards by a bit less than 10 cm. This is before winter snow loads.

    I’m surprised and worried because everything here seems to indicate a structural stability problem, the seriousness of which I have difficulties estimating.

    The bales are 1.2mx2.4mx0.7m, and about 170kg/m³ in density. The ground floor is 4 bales high, the first floor 3. The roof is a hip roof for optimal weight distribution. The walls haven’t been rendered yet.

    We definitely stacked the already dense bales too densely together. This gave us extreme bulging, even pushing the 10x10cm window opening studs into a bit of an X shape in some places. That’s something we’ll have to fix using the hints you gave us here.

    I have a difficult time though imagining how too high density bales in too tight space combined with the vertical pressure could cause the wall to bend out of shape in the vertical axis.

    How worried should I be? Any hints or suggestions on how to handle this?

  4. Hi Mark. That’s tough to answer without seeing the project first hand, but it sounds like you may have overstuffed the walls simply by the pressure added to them during the stacking process. When there are forces acting over the top of the thresholds the wall can manage, the excess energy has to go somewhere. If it can’t escape the wall system in any other direction, it will bow out. I don’t imagine it’s a deal breaker, but you want to get it right for sure.

    You may be able to relieve some of the pressure by simply removing some of the straw from the bales. Even a little removed by hand can be enough to allow things to relax into position. You should definitely check the integrity of the bale strings and any other confining detailing you have in place (mesh, lath, etc.) before removing straw as if those aspects are weak or failed, then removing straw may make things worse. Hope that helps.

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