How Long do Straw Bale Houses Last

How long do straw bale houses last? If you’re just starting out on your straw bale journey, then this is probably something that’s on your mind. Vermin, termites, and water damage are possible concerns, as is the prospect of bush fires. Reassuringly, straw bale houses can last just as long, if not longer, than traditional brick or weatherboard homes.

When you’re making the decision to build your own home, it’s important to take the ongoing maintenance of the house into account. As far as I’m aware, there are currently no products out there which will last forever. And if they did- would we even want to use them? Eventually, all houses will succumb to inevitable decay. When that happens, it is nice to think that the materials will return to the earth- nourishing new life and making space for new homes.

When the time comes for a straw bale home to be demolished it’s nice to know that the straw bales, which make up the bulk of the building, are 100% biodegradable.

But what of their lifespan? Well, good news! A well maintained straw bale house can last over 100 years. This is about the same as optimistic brick construction, and better than high maintenance weatherboard homes.

Historical Examples

While straw hasn’t been utilised as a building material for as long as bricks have, it has still been used to build homes for centuries. Loose straw was mixed with mud to make cob, and used to thatch roofs. It’s not until later, with the invention of baling machines, that we see straw’s real potential.

{Photo from Straw.com.au}

Bales of straw started to be used for building construction in the early 20th century. The famous straw bale church in Nebraska (see it here), was built in 1928 and is still in use today. It is one of the oldest surviving straw bale buildings.

Chuck Brunner, an owner builder in the US, built his straw bale house in 1949. The bales in the walls were checked by a building inspector around 2009, as Brunner wanted to widen his front doorway. Brunner stated:

“She was flabbergasted, the straw looked just like it did the day I put it in.”

– Chuck Brunner, The Torrington Telegram, April 2019

Maintenance

All homes, no matter the construction method, need to be maintained. If they aren’t, they simply will not last. Everybody knows one of those sad houses – once beautiful, but now tragically neglected. Knowing the vulnerabilities of any home means you can keep ahead of any potential damage.

For straw bale homes, it is imperative that you keep the bales dry. Encasing them in render, making sure you have adequate eaves, and creating safety margins in wet areas are all important measures to take during the building stage. (See our article on Straw Bale Installation for more information).

rendering a straw bale house

Repairing cracked or worn render is a comparatively easy maintenance task. You can accomplish this yourself, or you can hire somebody to apply another coat of render for you. Mark Beedle is our contact for rendering in Victoria, and his render pump means he gets the job done quickly. You can see our recent article on render repairs, for an easy way to repair cracks and damaged areas.

Other vulnerabilities are not straw bale specific, but should be considered part of any house maintenance:

Make sure timber stumps or concrete foundations are kept dry by creating good drainage around the house. Check stumps for signs of rot, and have them replaced by a professional if they are affected.
Use appropriate termite-proofing (as outlined in your engineering design), and know what termite signs to look for.
External timber (as in doors, windows and fascia) will need to be repainted every couple of years, depending on your climate. The natural expansion of timber, as a response to fluctuations in temperature and moisture, can lead to cracked and chipped paint.

drainage around a straw bale house

{Red brick path, angled to drain water away from the house}

Straw Specific Concerns

Can straw bale walls be damaged by rodents?

It’s important to differentiate straw from hay. Hay is the food that pests are attracted to, whereas straw is the waste product made from cellulose.

As long as you seal up the walls with earthen-lime render, mice won’t be able to get into the walls anyway.

{Photo by Yunu Dinata on Unsplash}

Are straw bale homes more susceptible to fire?

No. CSIRO has tested straw bale walls. They found that due to the density of the walls when compressed, there is not enough air trapped within to promote combustion. The thick coat of render is an added layer of protection against fires.

As such, straw bale homes perform better in most bush fires than many conventional houses.

Will termites eat the straw bales?

termite capping on timber foundations There are few types of termites that eat straw, and the biggest threat from these insects is to your timber doors and windows.

Using appropriate white ant capping is one of the best ways to protect your house from termites. Refer to your engineering specifications to see more specific information on termite protection for your home.

Will humid climates make my walls rot?

There are some humid parts of Australia (like northern Queensland) where straw bale homes would not be appropriate. Rendered straw bale walls are made to breathe. If the air has constant high humidity then mold and rot can ensue.

However, there is little to no risk of this in the rest of Australia.

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Do you have any further questions about maintaining straw bale houses? Or are you ready to start your owner builder adventure? Please let us know in the comments below!

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