strawbale v earthbag

Discussion in 'Designing, building, making and powering your life' started by beanni, Feb 13, 2013.

  1. beanni

    beanni New Member

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    Hi all my first post here so please be gentle. I have been interested in permaculture and sustainable living for 15 odd years now but have only ever made half arsed attempts at practising it. However I am hoping that is all set to change. In the next few months I will be returning to Australia and to my family's property of 20 something acres on the Central Coast of NSW.

    I have all manner of permaculture related ideas for the site but first things first is shelter. There is a large 4 bay shed on the property with the 4th bay completely open on the western end of the north facing shed. My plan is to infill this open bay with strawbale or earthen bag.

    I was wondering if there was anyone out there that has experience with building/living with these materials and if they would be willing to share their experiences. I am particularly interested in - ease of build (I am a complete novice to building); ease of maintenance; comparison of insulative properties compared to thermal mass between the two and how this relates to comfortable indoor living.

    Finally if anyone has other suggestions for my area (2 hours north of Sydney 30km from the coast) I am very open to all ideas. I know that the use strawbale is often considered an unsustainable practice and I am also concerned about the manufacturing process that the bags for earthen bag construction may go through and any leaching of chemicals that may occur into the living spaces.

    Thanks all
     
  2. gardenlen

    gardenlen Group for banned users

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    g'day beanni,

    just opinions and from what i have observed, straw bale at least is on the top end of high cost addition, also something i've seen others get caught with is they don't account for the thickness of the bales ie.,. if you want a 6m X 9m dwelling then you need to make the slab out to 8m X 11m to accommodate the bales and same considerations if bales are used to create rooms. some one down south did so and had to leave out rooms to simply have some space sadly of course now less space than they were replacing when they wanted more.

    saw a gable straw house with cathedral ceiling in the US no where near enough windows no indication to aspect of the house for winter sun, and a huge 6 blade maybe 6' fan, my guess is in summer gets very humid in there. no matter what is used land aspect and the orientation of the house to keep our summer solstice especially on the back wall of the house in the arvo' is still a serious consideration, the narrow ends of the house should be oriented east/west. we got our place better orientated this time about 5 degrees west of magnetic north looking for true north of course, but after our first summer here now we got no arvo' solstice sun on the back wall. bale homes may be super cozy in winter but then the price in summer could be at least higher humidity?

    dunno about earth bag or compacted earth termites do like to move about in earth, we build termite and fire resistant homes. scillion roof better than cathedral gable. we had to settle for gable money was short and builders really have no idea. we reckon a scillion roof should at least be no dearer than a gable, but they don't have that knowledge.

    https://www.lensgarden.com.au/eco'_home_essay.htm

    the straw comes from broadacre farms where massive habitat degradation has occurred. and where would earth come from if it is not dug up from the habitat?

    len
     
  3. abdullah

    abdullah Junior Member

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    since the roof is already free standing, why not frame it out with recycled timber, clad the outside with recycled sheet iron, maybe even cinder block or brick (recycled of course), get creative with insulation and interior lining, have plenty of windows and ventilation (aluminium frame sliding windows are plentiful on ebay). maybe even forget the frame and just go double brick (recycled of course).
     
  4. gardenlen

    gardenlen Group for banned users

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    good idea abdullah,

    we get second hand roof iron from scrap yard it is in a very usable state, costs around $100 per app' 40 lineal meters, we've built our gardens with it, and got some for the chook house. do more on teh steel side, wood gets eaten by termites and burns.

    did you have a peruse of our idea of an eco' home?

    len
     
  5. Donkey32

    Donkey32 Junior Member

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    I've built with both.. Honestly. I don't think much of the earthbags.. They are quick to build, but you need to cover those bags right away, they can't handle too much sun exposure before they disintegrate. I doubt their suitability in earthquake areas and I'm not much into having the plastice bags in my home.

    Bales can be nice if you take their particulars into account. Bales should sit up on a high foundation to keep 'em out of rain splash, they should have big long eves overhead as well. DO NOT cover them with a moisture barrier and NEVER use cement based renders (stucco). The old books show rebar pinning through the bales, don't do it. Firstly it does very little to nothing and just trying to get the pins through the bales is a major headache. Exterior pins, of bamboo or some light, thin, long poles work better. Instread of ramming them through, place them inside and out (adjecent to each other), sew through the bales with baling twine (use a baling needle) and tie them tight. This will do a FAR better job of securing the bales and is WAY easier to deal with.
    There are SO many little tips and tricks, I could probably write a book on it.. Not here, not now.
    Anyhow, if you have any particular questions about how to go about bagging OR bailing, I'd be glad to help.
     
  6. Pakanohida

    Pakanohida Junior Member

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    It is my understanding from 7 years of research that Earthbag is actually the best material to build any home with currently. Earthbag systems have destroyed, that's right... ..DESTROYED... the machines used for testing walls for Earthquakes; The walls were that strong. Here is some more information.

    Strawbale homes are even used in rainforest areas such as where I live. Cob Cottage, last time I was there was doing interesting tests using a combination of Strawbale & Cob.

    As I am still clearing my foundation area, I am most likely using a combination of all 3 methods. ((Cob, Earth bag, and Strawbale))
     
  7. Donkey32

    Donkey32 Junior Member

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    Cob Cottage "balecob" (strawbale/cob hybrid) works very well. I have been using the technique for a number of years with very few problems.
    An interesting benefit when you mix bale and cob is that the bales can be cut in half, which makes for a more convenient footprint (stemwall width) while still providing oodles of insulation.

    Pakohinda,
    I'd be curious to see more info on earthbag quake tests.
     
  8. Pakanohida

    Pakanohida Junior Member

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    Earthbag building
    https://www.earthbagbuilding.com/

    Lots of books to buy
    https://www.greenhomebuilding.com/earthbag.htm

    How stuff works
    https://home.howstuffworks.com/earthbag-home1.htm
     
  9. abdullah

    abdullah Junior Member

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    i recently spoke to a builder who has been in the industry all his life and built his own house (and many others), i told him i was thinking of building my own he asked what i had in mind, i inferred unconventional, he emphasised stay away from strawbale, claiming the maintenance and upkeep is significant and you loose a lot of floor space to the thick walls, he reasoned further when thinking of building that (paraphrased) 'in the life of every home, there will be a period of neglect, often a decade or more, could be due to a family split up or move or whatever the reason, during that period without maintenance, what will happen to the dwelling should be considered'.

    kind of off the topic but interesting nonetheless:
    this builder built his own house first with a steel frame to hold up the sheet iron roof, then he spent the winter pressing mudbricks under cover with an appropriate technology gadget invented by 'someone rockerfeller', his bricks have a bit of cement in the mix so they dry in one day, the cam system of the hand operated press compresses the brick only a millimetre, but that millimetre makes a very solid brick, because they only take a day to dry, he could press 100-120 a day, lay them out under his roof, then the next morning stack them aside ready to press and lay out the next batch.

    granted it took a long time, but 30 years on his house is as solid as it was when he built it.

    anyway he suggested after some consideration, that the easiest and possibly cheapest dwelling, that whilst would need some work to improve the energy efficiency, is the good old 'portable classrooms', they can be picked up for under 10 grand and moved for the same (requires specialised movers), they are already 'built' so permits are less hassle (just got to get the footings right or something like that).
     
  10. abdullah

    abdullah Junior Member

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    food for thought (for cheapskates like me)
     

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