I’m often asked if using bales that are tied with wire is a bad idea or a good idea. Perhaps it’s worth sharing my perspective here on the site so that others with the same question can get at least one point of view. I hope you will share your thoughts on the matter below so that the “point of view pool” can get deeper.
The reality is that there are advantages and disadvantages on both sides of the question. I do have a preference though, and that is for poly twine over wire. The main reason for this is that the poly twine is much easier to work with. It cuts with a knife. It doesn’t cause damage to my tools (or me personally) if I mistakenly hit it with a chainsaw, etc. It is soft and flexible, yet strong. It really makes everything easier.
Wire ties on bales have one distinct advantage over poly twine and that is that they make the bales incredibly tight. The baling machine is able to get the bales much more dense with the metal ties so the uniformity of the bales is improved as well. If you don’t plan to modify the size of many bales in your project, then perhaps metal ties are the way to go. If you are willing to work around the potential danger of using wire and the hassle of retying bales with it, then it could very well be a good match, especially if wire tied bales are what are most readily available in your area.
Jumping back to poly twine, it’s important to note that not all twines are created equal. There are several different grades of poly twine meant for different uses. For example, there are very thick twines which are designed for use on jumbo bales, and there is very thin twine which is primarily used for flossing teeth (just kidding, but it is too thin to use for straw bale construction). Making sure you have the right twine is important. As noted, the thin stuff is no good for baling a house; however, neither is the big stuff. It’s too much like working with rope. My preference is for “super blue” (my name for it) twine. It is designed for use on three string bales and is both strong and easy to work with.
Here’s a tip about finding the right twine. The size of the bale of twine, the round spool that comes in pairs of two in a box of twine, is a set standard. This is because the baling machine into which the twine has to fit has a specified chamber for the bale of twine. As a result, you can tell the strength of the twine inside a box without ever having to open the box. Check out the length of the twine in the roll.
The longer the length, the thinner the twine has to be in order to fit into the standard twine-bale size. Don’t use anything that is longer than 9000′ unless it specifically states that it is reinforced for added strength. My favorite, the super blue, is 5000′ long. As you can see, it is almost twice as strong as the standard 9000′ rolls.
As a final note, do not use natural twine. Although the desire to have a natural house, made of all natural materials, is high, the simple fact of the matter is that the natural twines are not strong enough to effectively tighten a bale or attach mesh to a wall section. The natural materials break under a little bit of force, and you will need to apply a lot of force to the twine when building a straw bale house. As much as I would love for the natural, biodegradable twine to be an option, it simply is not.
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One other argument against tying bales with metal is that leaves wire ( a condensation point because it’s cooler than the straw) deep inside the walls. Condensation may not be a big deal when building in a dry desert climate, but it IS a major concern when building in a humid climate like those found east of the Mississippi.
I second the vote for “super blue” (or the equivalent- in KY that weight is orange). You really do apply a good bit of strain on those strings when pulling the bales tight. We started off trying to reuse the existing strings when we cut bales, but found it much easier to just go ahead and use the stronger twine so it wouldn’t break.
Andrew, thanks for sharing so much useful information!!!
Hi,
I’m not yet ready to build a house but I’m wondering if a “cube” style house could be built with straw. I plan to buy land and then build if the codes in NYC will permit. Any advice, ideas?
Thanks
I’m not sure what you mean by “cube” style. Sorry. I will say that Matts Myhrman, a long time straw bale advocate, once said: “You can do anything with straw bale construction except have thin walls.” I’ve always loved that.
My biggest concern about a “cube” house (if I am thinking of the right thing) is the flat roof and zero overhang. Water is the biggest enemy of straw bale construction and protecting the walls from water intrusion will be hard without a pitched and overhanging roof.
Andrew, thanks for the info on poly vs wire. Some questions:
1) Is there any difference in longevity between polypropylene and wire? I don’t want bales coming loose in 50 years. Which do you think will last longer?
2) Some poly twines have manufacturer ratings for tensile strength and knot strength. What are those specs for the twine you recommend?
3) Here in Texas, walls can get quite hot in summer. Does the heat cause poly to stretch? I hear it has a low melting point, and I’m curious about its behavior as the temperature rises.
Thank you.
Hi Mark. My answers are below.
1. The longevity is not an issue as, once installed and plastered, the twine becomes somewhat irrelevant anyway. More directly answering your actual question: as long as the twine is not exposed to UV light, it has a long lifespan.
2. Unfortunately, I don’t know the answer to this question! I don’t have any around to look at right now either. I buy it based on the length of twine within the roll and I believe it is about 4500′ per bale roll. Sorry I have never paid attention to that!
3. I have never seen heat cause the twine to stretch. Again, once in the wall, it won’t matter, but when stored for your build, I imagine the outer bales could be impacted (slightly). The bales inside the stack will be fine because they will be insulated by the other bales around them.
Very interesting info Andrew! I for one, will admit that when I was researching straw bale building for my house, I didn’t even think of what kind of twine would be best! (plus, I didint’ know you then either!!)
Fortunately, my bales were made with the polytwine, but the rust coloured kind. I’ve actually never seen the blue one. Now, lots of farmers around me use the natural twine, so , when I build my extension, I will be sure to take this into consideration and make a point to check what kind of twine the farmer will be using!
I’ll bet that this is a topic that many of us straw bale home owners didn’t even think about!
We live in the Kootenay region of southern British Columbia. We have a large number of wetlands and lakes near our farming areas. Red twine has proven to be very hazardous to our osprey bird population. They scavenge for it as a nest building material. It frays easily and their legs,claws and babies get caught up in it and they strangle or cannot move. It used to be a sad, familiar site but now most of the valley farmers use the blue kind which the birds don’t seem to like.
We did have some bales with red twine when we built our strawbale house over 20 years ago, we didn’t like using it either. We were very careful to not to leave any scraps lying around for the birds to find. We also had some flax bales with natural twine which didn’t work well for the house but made great garden mulch!
Great article! Can you recommend name brands of your super blue and locations for purchase?
Hi Tina. I don’t know the name brand of the one I use and I don’t have any on hand to check. I order mine from the Grange Co Op here in town as they don’t stock it. You might also contact other farm supply stores in your area to see if they can order it for you. It is basically the twine used on a lot of three string bales. High strength, yet not super thick rope. It’s still twine.
Hi Andrew.
Thanks for the insights!
We have been using the natural stuff but had to double it to make it strong enough. That uses twice as much twine!
May need to check out the blue stuff…..
Jeni in Bali
I highly recommend it. After all, even when doubled, I break the natural twine when using th eMiller’s Knot because I can put so much tension on that knot and thus make super tight bales.
Hello,
I am an apple grower in NY and am deliberating on whether or not to use poly bale twine as tree support in my orchards because I have not found information on its life expectancy. Would you have any insight on lifespan of this material when it is fully exposed to all elements throughout the year? Any information would be greatly appreciated. Thank you!
-James
Hi James. The poly twine is very strong; however, it breaks down fairly quickly in UV light so direct sun is not good for it. I don’t know if this would be a good long term solution for you, but I’m guessing not.
Hi James –
For what it’s worth, I’ve used the poly baling twine (left over from hay bales I’ve used to feed my horses with) braided together to make a “rope” for a temporary fence out here in Northern Colorado. The fence is still up, two (three?) years later, albeit a bit frayed. And, under tension, it will tend to stretch a bit over time, so you may want to build in a mechanism to tighten it up now and then (I use a “trucker’s knot” kind-of-thing).
Laying on (or buried under!) the ground, the stuff lasts nearly forever. I’ve come across stray pieces in the pasture that I presume had been there for 5+ years.
Bottom line, it will work for tying up your branches, and while it will last a while, it isn’t a really permanent solution for years and years. Also (and you probably already know this), you’ll have to watch that it does not cut into the bark, or that the bark does not grow around it as the tree grows.
That’s just my opinion – I don’t have an orchard, but have used it to “help” a few of my trees grow in the right direction for a few years until they can do it on their own.
Hi Andrew,
I have a question on wire-tied bales. Do you, in your expert opinion, believe that the wire will attract condensation as it leaves the inside of the building due to cooking, bathing, etc., I know you said earlier, that wire-tied bales would be very tight, which is a plus, but will I have cause for concern later down the line?
I don’t think they will be a problem. The wire is 1) relatively thin and 2) typically plastic coated.