Cob vs earth bags vs straw bale

[thecornflake]

Recently I've been looking into cob as a possible method for building a house cheaply as the materials (depending on location) are easily accessible and I could do a lot of the work myself. It also looks like it's much more acceptable now in terms of gaining planning permission. I'm also considering straw bale as that's been around for some time now and is well proven. In the last few weeks I've now seen a couple of buildings on various tv programs using the earth bag method (usually coiled with rounded walls which I like) and I'm wondering how that compares to the other two if anyone knows or has any experience of these?

[Green Aura]

I'll be watching this with interest.

I know there are cob houses around that are two or three hundred years old. Are there examples of straw bale or earth bag houses that have lasted so long? I've often wondered why the straw, or the bags, don't rot.

And there's also rammed earth - you know using old tyres - to consider. I like the idea of reusing waste materials to build something new and wonderful. But then I'm a sucker for an earthship!

[diggernotdreamer]

We have a thing called Green Door here, where people that have done eco stuff and rebuilds open their doors over a weekend to show people what they have been up to, they are running this course, there may be something like this where you are, but it gets a lot of interest http://inspirationalhomes.ie/9-day-buil ... kshop.html

[thecornflake]

Well definitely with straw bales for house building they're treated with stuff that is fire retardent, deters pests etc. This plus how tightly they're packed, very dry and then the fact they're covered with some sort of render I think stops them from breaking down at all.

There's a guy who built a massive cob house to prove it could be done, and actually cob etc is just effectively dried mud that presumably also bakes a bit in the sun, not that dissimilar from a basic brick. I started looking at it because I actually love the idea of having a big roundhouse, but then also adding smaller units for bedrooms etc and a lot of roundhouses were cob.

I did also see the earth tyres system, will have to look into that more.

The green door thing looks great, I was actually thinking about looking for people who've built similar things and seeing if I can go and visit them.

[doofaloofa]

The drawback to cob and rammed earth/tire is both techniques are excessively labour hungry

Start endurance training now

[diggernotdreamer]

I would agree with the labour involved with earthships and cob etc. Personally, if we ever built a house of our own we would build one from wood in the Walter Segal style

[ina]

I know there are cob houses around that are two or three hundred years old. Are there examples of straw bale or earth bag houses that have lasted so long?

The modern kinds of straw bales haven't been around for that long... So I suppose we'll have to wait and see how they do long term!

[mamos]

I would like to build a round house like Tony Wrench's. I think wood frame, straw bail infill and cob render is a good combination of cheap, easy and quick to build with outstanding thermal properties.

paul

[Green Aura]

I think he calls it a cordwood house (or at least I'm sure I've seen that somewhere. I love them but I don't think they'd survive up here - the cut end wood wouldn't survive the damp for very long.

I'm still holding out for OH agreeing to build me an earthship - I've even sourced the tyres.

[doofaloofa]

I have recently deconstructed an chord-wood round house due to the untreated structural posts rotting

the chord-wood, and cob mortar were in very good shape despite 12 years in the west cork mist

[snoweyjoey]

Hi all, I am new to this great looking forum :)
I have lived in a straw bale house (small cottage hexagon type) and we absolutely loved it despite the rats!!
We are now looking to build something in a field in Cornwall where we have moved to. I had never looked at cob or earth bags. I don't fancy the earth bag idea as much, but cob looks well worth a look. Can I ask if anyone here knows what the main pros and cons are between straw bale and cob type construction?
I assume straw is a better insulator (which was LOVELY) but cob seems stronger and easier to build for someone like me with little knowledge of carpentry/engineering/building. Anybody have any advice or experience between the two types?
Many thanks, I can see me spending a lot of time on here! Cheers

[Green Aura]

Hi snoweyjoey and welcome to Ish

I can't help you on any technical details and you've said you'd rather not use earth bags but look what came up on my FB feed just now.

http://www.offgridquest.com/constructio ... red-homes2