Straw Walls: Good Idea Or Not?

Straw has countless uses. It’s a waste product that comes from wheat and rice and is used for a number of applications on farms. It’s been used in countless places as a construction material, though you’ll often get weird looks if you actually mention that fact. It actually has a pretty good place in construction for straw walls. However, there are a few things to keep in mind when planning to use it heavily in your home.

Straw walls are entirely acceptable as an alternative to traditional walls, and actually have some surprising benefits when properly installed.

Let’s talk some more about that, yeah? I can’t just say they’re a good alternative without explaining why, after all.

Straw Walls: The Good

Let’s start with the good side of straw walls, shall we? We can get into the less-desirable factors in a moment, but for now, let’s talk benefits.

Cost

Straw bale walls are actually surprisingly affordable. This is because (as mentioned above) it’s a waste product. That means that farmers often sell it off for an affordable price because the other option is the landfill.

Keep in mind, however, that your mileage may vary on the cost of straw bale. Your location and timing will both play heavy roles in how much it costs to get enough straw to actually do the job right. Ordering straw bales 6 months after most grains have been processed means you’ll have a harder time actually acquiring enough to use. And if you don’t live anywhere near where someone might actually be selling straw, you’re going to have to pay to get it shipped to you. You’ll need to do a bit of local detective work to find the best source and material for you.

Insulation

This is something that will actually catch a lot of people off-guard. Believe it or not, straw bale is actually one of the best insulating materials you can find! The average straw wall will have an R-value between 35-60, depending on the thickness of your walls. Traditionally, straw bale walls are at least 45 cm thick. This averages out to an R-value of R-18 per 2.5 cm, while commercially available alternatives generally max out at around R-6 per 2.5 cm.

This is due to the way that straw acts when compressed. It’s able to compress to prevent air from making its way through, assuming it’s installed properly. Some factors that may affect this are:

  • Your chosen roof insulation
  • Post-and-beam structure of the walls
  • Loadbearing sections of wall
  • Type of wall plaster
  • Quality of plaster
  • Home shape and design
  • And much more…

Fire-Resistance

This is another often surprising fact about straw bale homes. Surprisingly, it’s actually quite fire-retardant. This is due to the same reason it’s so good for insulation – it compresses, preventing air from making its way into the bale.

Now, this is up for debate in the construction community. Depending on who you ask, some will tell you that this is just a myth, while others will swear by it. And if you don’t believe me, there are actually a few studies that enforce this claim.

But if you live in an area prone to wildfires, it may be best to opt for a truly fireproofed building medium like concrete.

Carbon Footprint

Because hay is a natural byproduct of the most common grains out there (rye, wheat, oats, barley, rice), it’s got a minimal carbon footprint. This makes it a wonderful alternative for those who want to be a bit more eco-friendly when building their home.

It takes nearly no energy to harvest hay bales (especially when compared to the impact that logging and timber transport has). This, in addition to its light weight in comparison to concrete or masonry, means that it’s easier and more eco-friendly to transport as well.

And if you happen to live in the States, you’re in luck. Nearly every one of the continental States has some place in which hay is produced. This makes it easy to obtain and often a cheap, locally-supporting option that will make you feel a bit better about its use.

Also on the note of eco-friendliness, straw is biodegradable! Of course, it won’t happen any time soon – straw home can last well over 100 years if built and maintained properly. This allows you to (when ready) simply return the straw to the earth when demolishing a home. This cuts the need for throwing fibreglass and other nasty materials into the landfill to sit for another 100 years.

Fast and Pretty

Believe it or not, stacking bales of hay is drastically faster than building a traditional wall. Add in that it looks pretty darn good when finished, and you’re gonna be very happy with how it comes out.

The one downside here is that straight lines are hard to achieve with hay bales as they settle. So if you’re extremely obsessive over having perfect lines (I mean, who isn’t) this may be a bit offsetting.

Straw Walls: The Bad

Now, straw walls aren’t all good. There are some downsides that you should be aware of before continuing.

(Not So Wide) Use

This is the least impactful of all the downsides, assuming you can find someone who likes to use straw to build. Depending on where you are and who you ask, you’ll often be met with some pushback on using straw for walls. As it’s not super common across the world, local authorities, structural engineers, inspectors and building officials may dislike this idea.

That’s not to say it can’t be done, but it may take some additional convincing to be allowed to build.

Time & Its Cost

Because straw isn’t used as widely, there are going to be a few extra hiccups in the building process. It’s likely that most people (as mentioned above) involved in the approval and inspection of your home will have never used straw as a medium for walls.

This means that they’ll have to thoroughly research it before approval, and some inspectors may not go that far. Instead, it’s possible that they’ll just outright refuse you permission to build.

Add in that this increased time investment will cost inspectors and engineers money, and you may be looking at a more expensive installation. This could involve paying a structural engineer extra, or extra (unneeded) moisture testing. None of this is good, though it can be worked around.

Insects and Mould

Now, this is where staw walls don’t exactly shine. Straw is a naturally occurring substance, as we’ve discussed. That means that insects will be naturally drawn to it. In addition, straw likes to soak up moisture. If you live in a wildly wet environment, it’s likely in your best interest to steer away from using straw as a construction medium.

Straw can and will sink if consistently exposed to moisture. That means that using it in rooms like your bathroom, where showers and baths will add excess moisture is generally not the best idea. While traditional construction mediums like wood and fibreglass are also susceptible to both moisture and insects, straw is a bit more so.

So in short, bugs and mould can make their way into your home’s walls if you’re in a humid or wet environment. On the plus side, termites like wood, not straw, so at least you’ve got that going for you…

Loss of Space

Hay bales are thicker than standard walls. Generally, a stick frame wall will be roughly 15 cm, whereas a straw wall can be up to three times that thick at 45 cm. Sure, that extra-thick wall will allow better insulation, but it’ll be at the cost of physical space in your home.

You can always plan for that, but if you’re working on a limited stretch of property with minimal excess space, it could prove to be a problem.

The extra work that’s required to work around the size of the hay bales will mean that you’ll need to increase the size of your foundation and roof trusses, among other things. Those cost money – money that you likely don’t want to part with.

Stacking & Thermal Break-Points

Remember how I said stacking hay bales can be difficult to do in a perfect line? Yeah – this is where that comes into play. Especially if the person doing your building hasn’t worked with straw before, there’s a good chance they’ll miss a few things. Small spaces and gaps (such as spots where a full bale won’t fit) can cause problems when left alone.

Loose straw can settle if packed improperly, leading to a shift in your wall. This leads to thermal leakage, in other words – loss of heat and worse insulation. The best way to avoid this is to hire a professional who has worked with straw before to minimise lack of experience.

Plastering

Another downside to using straw walls is that plaster is perhaps the most important part of the whole process. Plaster and stucco are equally common in treating walls, and while stucco (when done properly) is incredibly sturdy, it can be hard to do right. The same goes for plaster, especially if you’re trying to do a quick DIY job.

A poor plastering can result in worse long-term performance and stability, as well as increase the chances of moisture or insect damage. It’s your wall’s primary barrier against the outside – so it needs to be done right. That means hiring a qualified professional, which will cost a pretty penny more likely than not.

No Regular Studs

This is a bit of a secondary concern, but because straw walls don’t use a stud support system, it’s entirely likely that you’ll have to find alternate ways to hang items on your wall. You can’t count on the support of studs, meaning you’ll need to hang heavier pictures, mirrors, and cabinets in alternative ways you may not prefer.

While this can be frustrating, it can also be used to your benefit! The fact that you’re forced to think outside the box for decorations means you’ll find creative ways to get around this issue. It’ll lend a bit of personality to your home (as if straw walls didn’t already) and can be a fun side-project for the DIYers out there.

Allergies

If you (like me) suffer from allergies, you’re likely already itching just reading this article. The thing is, even if you’re not allergic, it’s very easy to get irritated skin while working with straw. Add in the fact that you can inhale straw dust while working, and it’s not the most pleasant building medium.

But if you really think about it, the same goes for countless things used in construction. Fibreglass can produce dust and slivers that are painful and bad to inhale, as can wood – it’s all about perspective here. But one way or another, maybe wear a respirator when working with straw. And some long sleeves and gloves if you’re allergic…

Final Thoughts

In case you can’t tell, I love the idea of straw walls. They’re quite common in particular areas such as the southwestern U.S., and for good reason. Straw walls hold up surprisingly well over time, are sturdy, and offer excellent insulation. Add in the fact that they’re shockingly fire-retardant (more so than standard wood frames), and you’ve got a great option for building a home.

The major downside to straw walls, however, lies in their lack of commercial use. That and its dislike for moisture, and it’s not always the best building material. Sure, it’s relatively easy to work with, but you’ll likely have an uphill struggle when trying to get it inspected, approved, and built. While I personally find them incredible, especially for their greatly reduced carbon footprint, it’s ultimately up to you if they’re the right fit for your home. Luckily, there’s no need to worry about longevity, but you will definitely want to bring in an experienced contractor to help out.

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About the Author Harry Thompson

Involved in home renovations throughout his life, Harry is an expert in everything to do with home and garden DIY. In his spare time, he enjoys cooking and tending to his garden.