Straw bale construction

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#1

Hi Jeff, I’m a big proponent of the bandsaw mills, I’ve spent many hours working on a Woodmizer, and done a fair share of small scale logging. Sadly, the McMansions aren’t built with low energy, locally produced products, and many building codes or local planning authorities won’t allow lumber without an inspection stamp, having totally lost their common sense. In Manitoba a US based multinational forestry products company got forestry rights to a vast area of public lands to produce OSB, eliminating small mill operators from the entire area. Governments seem to like dealing with large corporations, apparently there is more bribe money available… :slight_smile: With cheap fuel corporations will move goods half way around the world to make an extra dollar.

Straw bale is very do-able, it just requires different building techniques, there are lots of successful buildings around. If you can end up with a fireproof, R55 - R75 building envelope, using local materials, I consider that a positive for the planet.

In response to Koen, there is now evidence that the majority of forests in north America are stressed, and have become net carbon emitters. In Manitoba there was good baseline data, the boreal forest as a whole here is losing carbon, due to stress and increased fire and disease. Probably the same is true across the northern hemisphere. Mountain pine beetles don’t kill forests, they clean up sick trees. Fires have increased for the same reasons. We can’t rely on forests to sequester carbon, they are having real troubles. Aside from which, unless we can set aside farm land to grow trees, the forested land on the planet is already doing it’s thing, which at best is a steady state, eventually it all burns or rots. I agree that bamboo or lumber locally sourced is positive, bamboo has exceptional potential, but the pressure is to increase cultivated land to meet the demands of growing population. Incidentally, without fossil fuel inputs, farming production would drop by over half, with obvious pressure on remaining forest. I believe the simplest goal with the greatest payoff to achieve is increasing the efficiency of cooking of the poorest half of the world’s population.

Regarding concrete, yes, it has a heavy carbon footprint. There are commercial rotating kilns using biomass as fuel. The bottom line is that we can’t sustainably gather energy from natural processes in a way that balances our present global lifestyle. Sweden estimated that they could maintain their vehicle fuel needs on wood for over 2 years before their forest resource would be exhausted. Never mind electricity generation, chemical processes, cement kilns, steel smelting, etc.

People forget that it used to be a lucrative commercial enterprise to send young men on ships from Nantucket on 2 year missions, to render whales for barrels of lamp oil, and lubricating oil. The lost men and ships were an acceptable cost, given how valuable the product was. Fossil fuel has changed the entire way we look at energy. We need to triage the entire system.

Regards,

Garry Tait

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Storing woodgas
#2

Garry, I tottaly agree about no common sense people. The fault lies with people not the forest/lumber. But the seeds of common sense have started to sprout, for example, there are already 10,000 tiny houses that can be built with any material you want. Interestingly the majority of tiny house owners are female, that surprised me. Also there is lots of interest in TSI (timber stand improvement) that’s my passion behind the tree cub and etc.

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#3

100_3950.JPG2304×1728 794 KB
40 x 40 keeps me out of the cold 8-10 hours a day.

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#4

Hi Garry, as a builder my problem is I come up on that kind of statement all the time in regards to stawbale buildings. If you want to make a comparison put it up against a super insulated shell project, a rated leeds silver or gold,or even better yet a passive house build. Something of the same square footage built with sustainability in mind. Strawbale proponents never do they compare their 1 story or storey and a half passive solar dream home to a lowest bidder subdivision house. I would argue any of the above high performing houses would outperform straw. There are uses for strawbale in the owner built category but as soon as you have to hire labour the competitive edge evaporates. In terms of wood sustainability I know two or 3 wood graders who will show up and grade anything. At least 3 or 4 portable sawmill guys as well. Roxul is produced in province from recycled iron ore slag. Wood siding that is fsc certified … it all depends on the money you are prepared to spend for sustainability. It’s about caring and sizing your dream for what the environment can tolerate not solely the building technique you employ.

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#5

Money, What’s money … Happy New Year folks … Have to go to a wake of one of my best friends tomorrow. Gonna be boring now and he was 3 years younger than me … As far as storing woodgas, the only person that took that seriously that I can recall is Bruce Jackson , I can’t do youtube but I think he goes by budasdad or the such there and you can find the videos of his gas storage adventures and many other woodgas things … Regards, Mike LaRosa

#6

I doubt that building codes would go for straw house here. Never had any luck with grass as an energy source, even tried compost heat. I do like grass root system in the soil and composted grass works nice in the garden soil. So easy to harvest wood on a small scale but a lot of equipment for grass and storing small bales sucks. I know because I used and planted about 35 acres of switch grass. Wish I started planting trees back then. Just my experiance, others milage will vary…

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#7

Hard to say what local building codes and inspectors will allow. CMHC, and DOE have published studies on straw buildings, rating the wall systems as load bearing, and with the R values I mentioned. Without going to extreme efforts with conventional materials and extra expense, that’s a hard level of performance to match. Here in Manitoba they will allow straw, but not as load bearing, post and beam, or reinforced with a minimal frame perhaps. The engineering stamp for post and beam costs about 3 grand. A maintenance shop, and a post and beam bungalow have been recently built in Winnipeg, probably others underway. I think the major impediment to greater use is conventional thinking, and a lack of experience in the building trade. In Ontario there are at least 3 outfits specializing in straw bale. If it passes herei t should be acceptable just about anywhere.

The owners report about the same cost per square foot as other construction, though that’s a little hard to follow, given the cost of straw bales, and the elimination of the insulation expense.

I think using the giant square bales for a shop or farm building would make a very superior wall system.

Garry Tait, MB

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#8

Hi Garry, surprisingly enough Chris has not dropped the hammer on us yet for off topic rambling but let me elaborate. I consider super insulated shells the way of the future. My reasons For considering strawbale a niche market are not based on a closed mind but based on a systematic analysis of the real costs of building one and maintaining one. I have participated in two builds and visited 2 more. There are drawbacks to them that might not be obvious. My main point was that good building is good building. Techniques change, materials change builders adapt but no single system solves the problems of our modern world. Imagine your mcmansion subdivision in strawbale. Is the world any better off? What of all those cleared fields now deprived of the carbon from the stalks year after year? Does a forest cleared for grain fertilized, pesticided truly lock up more carbon then a well maintained wood lot? See what I mean, grey… very grey.
With truly best regards, David Baillie

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#9

Just an odd side note… The snakes that get compressed into the bales are a turn off for me BUT I was never much for snakes. Not that that means anything. My grass varied and my balers was old and the tractor was geared a bit to high with no live PTO so my bales varied in density and shape which didn’t help with construction. It would have worked for something to put up temperarly for winter. Out west they use wire balers more and thighter bales that would help.

Interesting that lumber (post and beam) is still needed for house bales.

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#10

Hey Jeff unless switchgrass is hollow like straw you would not get the insulating qualities in your bales.

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#11

Hi David, I don’t think it is hollow but, if I can remember, I’ll check it out next year. The field is under water right now. I was using it to insulate an outside 2000 gallon tank of hot water. Hybrid compost and fire wood fueled.

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#12

Now that sounds cool… or hot I guess😂

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#13

Hi David, you are right, the discussion got completely off topic, but I think it’s been a good exchange of information and ideas.

Straw bale construction does constitute a super insulated shell, beyond most super insulation standards, according to published studies by CMHC and DOE.

Agricultural waste is often burnt, ag waste is often close to urban centers. 20 acres of grain straw would provide many building shells, yearly, a 20 acre wood lot could not.

I don’t see a conflict between better using agricultural waste, and woodlots. As long as we eat grain, there will be straw, which has to be burnt, or worked into fields with extra fuel anyways, so there’s no conflict between crops and timber. Small scale lumber is definitely a smart, and sustainable pursuit, always needed and versatile, but starkly different from the corporate lumber down at the home depot.

I agree that poor building practices can compromise any system, but that doesn’t necessarily discount the concept. There are many examples of long lived straw structures. Given the fire resistance, they should outlast stick frame. I am personally concerned about the long term integrity of OSB, eventually the resin should fail, then a lot of houses will just be wood chips.

I agree that housing should be far higher energy efficiency, far too much power is wasted heating and cooling homes, costing all of society. More efficient Mc-homes would be way better than standard practice today. There will be more than one solution to the problem, but I am unsettled when comparing cost with efficiency when fossil fuel energy is priced far lower than the true cost / value, skewing the figures.

Regarding better straw, flax straw is said to be about the best, grain straw is tubular, and conducts air through the bale wall. Performance is still high, the stucco inside and out stops air movement, but with less efficiency. I’m not sure how switch grass compares, but there should be published info.

Yes, the timber frame / engineering is ridiculous, but that’s a bureaucracy, common sense, or CMHC studies don’t seem to apply. At least it’s a foot in the door.

Regards,

Garry Tait, MB

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#14

I love this topic…

Researching for rice straw. Would that be do-able ?

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#15

Gary the timber frame is there to anchor the home to the ground and also to anchor the roof to the structure. Keeps the big bad wolf from blowing your house down

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#16

Have you ever seen pressed straw board? Similar to osb but not as strong as it doesn’t need the glues to hold it together.

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#17

I found a couple of informative sites that might interest you.

http://www.sunfrost.com/straw_bale_R_values.html

http://www.somaearth.com/natural-building-faq/straw-bale-insulation-r-value/

Pepe

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#18

Improving fuel efficieny of bio-mass cook stoves is Larry Winiarski’s life’s work. He’s a good friend of mine so maybe I’m biased, but I suppose he’s the best there is. Check out the real rocket stove. I think it can be found at the website for an org called “aprovecho”.
I’ve been in a lot of countries and seen a lot of bad fires. Smoke in the kitchen is one of the leading killers in the world today. In the 60’s there was a big push in the development world for liberty, the 70’s it was about hunger, 80’s clean water, 90’s it started to become about developing organizations and networking as well as vaccinations. Now all those networks are running around stepping on each others toes spending huge amounts of resources to compete for the few available resources. Those resources are allocated by govts and do gooders according to the hot topic of year. These days the hot topic is smoke in the kitchen. It kills a lot of people.

As for the use of farm land, etc. I found a good youtube: https://www.youtube.com/watch?v=cWC_zDdF74s
I don’t know if his numbers are right, but if you look in any dumpster or trash can in the country it’s not hard to believe.

He says that 40% of the nations food supply gets wasted. If that’s true, then 40% (or nearly that) of the farmland already under cultivation would not need to be cultivated to feed the world. There’s plenty of food. If you believe that farming has an overall bad effect on the environment—there are many different opinions on that subject but most would agree to this broad of a statement----then the simplest way to fix that problem is to stop wasting the food; but wait, that would require individual people to change they way they live. oops…thought I had stumbled into something do-able for a minute.

But you sound like you already know all this.
Billy

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#19

I’ve heard of straw board / panels, but can’t comment on their structure / properties. There have been commercial plants making a product equivalent to particle board from straw, including one in Manitoba. The plant here went bankrupt, too many quality issues - badly stored straw, rats got into their huge straw piles, etc. Basically bad management, but the board was good.

Regarding the big bad wolf taking a structure apart, there are various established solutions - all thread or other steel rod from the center of the footing through a heavy box frame top plate assembly, the entire wall compressed, the roof structure attached to the box frame, (hard to properly pin the bales on the rod as the wall is stacked), or steel rod anchored on both sides of the footing similarly tensions a top frame, or the one I think best, 3/4" steel banding threaded through poly tubing curving through the footing, cinched up with a hand bander over the top frame. Some are using the heavy fiber reinforced plastic banding.

Timber frame is labour intensive and anachronistic, requiring engineered structure and attachments, but it seems to strike the fancy of an unimaginative bureaucracy.

What I want to try here to appease the building inspector is to build a 2x4 frame wall on 24" centers, notch the bales as they are stacked to let them into the framing. From the planning authority’s point of view the structure will comply with their building practices for single story, the frame will ensure that the walls are straight and square. Then stucco wire inside and out, and shotcrete both sides. The exterior studding will serve as excellent anchorage of the stucco wire, and with wire ties can help anchor the interior wire. The wire and stucco serve as the exterior sheathing preventing racking. In fact, studies have shown that with a good bond, the wire reinforced stucco serves as the load bearing component, similar to a hollow core door, performance exceeding a 2x6 wall. With this information in mind, pre-compression isn’t really necessary, I would see it as more of a means to level out the top plate / frame. Compression would probably be more important in a true load bearing wall.

I wish I had built my cabin this way, but I didn’t have a square baler at the time, would have been a far better, quicker, and cheaper build.

In response to Koen, rice straw has been used in straw structures, and I believe it is rated highly. The DOE did tests on rice straw, compression resistance and insulation values were very good. In a tropical country I think precautions against termites would be necessary, probably have to sprinkle borax, or insecticide in the bale courses. As mentioned earlier, the structure should be securely fastened to a concrete footing, to be able to resist storm winds. The interior floor could be independent, made of traditional materials, packed clay, or whatever is locally available and accepted. I think straw bale building would be especially good in earthquake zones, It’s tragic to see people in such areas using the stone rubble from homes that just killed family members to rebuild the same dangerous structures. Also the time and effort it takes to rebuild with stone and masonry often leaves people exposed, or living in tents in bad weather, straw bale would give similar looking structures.

Regards,

Garry Tait, MB

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#20

Regarding more efficient stoves for the third world, this one is pretty accessible. I’ve built a couple, they work very well. If an NGO, or government agency could take on the manufacture of stainless steel pails and corrugated cladding, it could fundamentally change the world. Apparently 40% of global soot emissions come from open cooking fires, that could be significantly impacted, probably the cheapest forest protection and climate mitigation effort possible.

The food waste figures I fear are true, some say even higher. I credit corporate farming and food commoditization, and an urban population that has no connection to the land or respect for food, as long as there’s more. We should be able to do far better, but not without a revolutionary change of vision. Generally people only change when forced to, in this case the impetus could be an awful shock.

Garry Tait, MB

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