Armed Polite Society
Main Forums => The Roundtable => Topic started by: Gowen on January 11, 2010, 10:33:22 PM
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Does anyone know anything about straw bale homes? Or cob homes for that matter?
http://en.wikipedia.org/wiki/Straw-bale_construction
http://en.wikipedia.org/wiki/Cob_%28material%29
What I am interested in knowing is how readily will a bullet pass through a straw bale? I assume that a rifle bullet will pass through without much hindrance, but will it stop a handgun round? Where this is leading is, cob and straw bale homes have terrific insulative properties. A home built in this manner would be cheap to heat and cool. I want to know if it would be good construction for a safe house?
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I don't know about bullets, but I would be afraid of someone with a match.
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You want Insulated Concrete Form construction for insulation+bullet resistance.
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A lot of those houses are held together with rebar, pushed through and anchored in the ground. I see no reason why a sheet of steel or anything you want couldn't be included inside the wall.
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How would you anchor the steel so it wouldn't go toppling if something shifted? Do you know how much that many feet of sheet steel would be, or how incredibly ungainly it would be to try to move that size of plate steel?
I worked in a machine shop for a while, and sheets of steel that size are not easy to manipulate.
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Straw rots after the first couple of rainstorms (or generally moist atmosphere).
Not for me just yet. =(
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Just make sure there are no wolves where you plan to be building this.
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Considering that when we were kids the wooden arrows we shot from our kids bow (probably not more than 35 pound pull) would penetrate about 18 inches into the straw bales we used for a backstop, I'd guess that even a fat & slow .45 Auto would have no trouble going right through.
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I agree with Hawkmoon; a straw bale won't stop handgun bullets.
The adobe layer that makes up the wall might stop or slow some rounds.
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If you really want DIY bullet resistance, I think the earth bermed recycled tires filled with rammed earth takes the cake.
Add reinforcing mesh and a layer of gunnite for the exterior, and you've got a pretty cheap bunker as long as you don't count your sweat equity in your cost calculations. Since tires and earth are used as a backstop at gun ranges as-is, whatever gets through the gunnite will be partially deformed and not be doing well against the rubber, steel belts, kevlar thread, and compacted dirt after that.
IMO, even non-AP .50 BMG would probably be caught by the inside wall of the tires. A lucky hit between tires might get through, but IIRC, you zig-zag the tires two deep to make your walls and use a 1/2 alternating offset like bricks so it would have to be a perfect shot at a 45 degree angle, so the thickness of the wall is higher from the bullet's perspective, and the concrete would be thicker in the triangular joints between tires.
The one vulnerability/downside is that the "earth ship" type construction does not work on the principle of insulation, but on thermal mass, since the walls are quite thick. So you generally want some kind of south facing exposure, a solarium or greenhouse to collect solar heat in winter.
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The one vulnerability/downside is that the "earth ship" type construction does not work on the principle of insulation, but on thermal mass, since the walls are quite thick. So you generally want some kind of south facing exposure, a solarium or greenhouse to collect solar heat in winter.
While it's true that earth ships don't rely on 'insulation' as much as thermal mass, I'd argue there's a certain amount of insulation invovled when you have over a yard of dirt between you and the outside.
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Planning ahead?
[tinfoil]
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Planning ahead?
[tinfoil]
That's funny. =D
I'm listening to "One second after" and it get's a person thinking. Thank you for the responses.
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Ok, several points.
Ya'll really need to look into strawbale construction. Settlers on the plains in the 19th century used them and they are still being used and developed. Moisture is not an issue when they are properly constructed. Which means having a large roof overhang, stuccoing the exterior, and having a damp-proof course.
They are much more resistant to fire than stick frame construction since there is not enough air in the bale. This is an established fact.
now, regarding bullet resistance. You can't compare it to a loose bale that you shot arrows at because the bales are compressed with twine and the the roof that sits on top of them.
During the war between the states confederate soldiers used hemp bales to advance on union troops near lexington, missouri and defeat them. This became known as "the battle of the hemp bales"
I haven't found any data on this online, I guess cause the people that use them now are mainly hippys. I'm thinking they'll stop handguns and shotguns and at least slow down a rifle. If you had interior and exterior concrete stuccoing with steel reinforcement and compressed them well you'd have a fairly decent little fortress.
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Never been more jealous of anyone than the guy who built a cruck frame, straw bale insulated house that Grand Designs filmed.
http://greenconstructionuk.files.wordpress.com/2009/02/ben-law-sbh-11.jpg - link because the image is huge.
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Hay bales are compressed with twine as well and won't stop arrows much less bullets. I still wouldn't trust it. I don't know if I would compare straw to hemp.
Has anyone ever tested the bullet resistance of thicker sheets or layers of hardy plank?
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(https://armedpolitesociety.com/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Ff%2Ffe%2FStraw-bale-construction-john-cross.jpg&hash=e555a5be0cfa5400690695d737ce045efac649f4)
This only looks like a bit more dense than hay bails. I wouldn't expect it to stop much at all.
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That's funny. =D
I'm listening to "One second after" and it get's a person thinking. Thank you for the responses.
yeah, that's a great book
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30-06 goes right through 4 bales, I use stacked bales to make a highpower target backstop during the summer. 6 deep is a minimum.
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Another thread I thought dead and buried. :O
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We have some neighbors who built a straw bale enclosed porch. Our daughters helped them a lot with it.
I'm not terribly impressed. There's a lot of labor that goes into it, beyond just stacking the bales. Stucco is pretty labor intensive. And they had to buy a lot of hardware like steel cables and turnbuckles to cinch it all down. Of course, you still have to build a floor and roof like anything else. I could have built a wood framed porched in about 1/10 the time.
Upside is that it's very well insulated. And they already had the straw bales.
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This only looks like a bit more dense than hay bails.
Bails are on buckets. And, no, a straw bale won't even slow down a handgun bullet.
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I don't know about bullets, but I would be afraid of someone with a match.
or a Big Bad Wolfâ„¢.
[popcorn]
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I don't know about bullets, but I would be afraid of someone with a match.
Loose straw burns well. Straw bales don't. Especially when covered with adobe, stucco, etc.
http://www.ecobuildnetwork.org/pdfs/Cement_Stucco_Wall.pdf
Straw rots after the first couple of rainstorms (or generally moist atmosphere).
Not for me just yet.
Again, loose straw rots pretty quickly. Straw bales that are plastered, covered with a roof and good overehangs, not so much. Straw Bale Building and Serious Straw Bale both talk about vapor migration and water instrusion from cracks in the plaster or leaks around windows, doors, etc. I wouldn't build with straw bale in the rain forest, but only because there are much more appropriate materials like cedar for that.
The OP was asking about bullet resistance. I would say that straw bale walls are probably a little less resistant that a stick built house.