The Natural Home discusses some issues with solar gain and the different materials one can use to build a house. They had some very interesting comments.
They mentioned that when considering thermal mass, dry stracking concrete blocks or using poured concrete is just as effective at holding heat. They suggested this was easier than tire pounding, which resonated with me.
- Earthships (using recycled tires for your walls) are obviously less expensive in terms of materials, but any savings is quickly overshadowed by the increased labor. That happy glow from recycling tires will be of little consolation to your sore back after ramming hundreds of wheelbarrows full of dirt into those endless radials.
So I emailed the architect to ask his opinion on constructing with blocks. The concept is interesting.
- If you want to use conventional mortared block walls or poured-in-place concrete, go right ahead, we're with you all the way. It's just that dry stack is worlds easier for the unskilled homeowner-builder. You don't have to have any experience with laying block to dry stack!
He responded back with the fact that tires and concrete block are the same. Compacted earth, concrete and rubber all have R-1/inch. He also said that tires can definitely done by unskilled labour while concrete walls not so much. He has a point there, I looked up info on stacking the bricks and for me personally, even without mortar, it still looks more difficult than tires. From my perspective, I would still probably have to hire masons, which eliminates any costs savings from either method. At least with pounding tires, I can do it myself and volunteers in trade for knowledge are numerous.
He did have some good news though. He realized that pounding tires is a PITA and that people do want an easier way. He found that cutting off the top rim of the tire makes pounding way faster, since there is no side pounding necessary. He built a small structure with 80 tires and was able to finish in a day in a half what would normally take 7 days. There was also a study done to prove that this method was just as safe and effective as not cutting the tops off of tires. Yay!
Thank you. This is EXTREMELY helpful. If cutting the top rim off of the tire is just as good as packing in the sides, that makes it practical to use a machine. You have made my earthship dream that much closer to reality, and I am VERY VERY thankful.
ReplyDeleteThanks and I know how you feel! I was very happy to hear that tidbit of advice!
ReplyDeleteIf all goes according to plan, I should be able to start work on mine in a year or so. If I remember, I will keep you posted.
ReplyDeleteDid you build it?:)
DeleteI plan on using Styrofoam and rubber insulated concrete walls as well. You should document it somehow for the rest of us.
ReplyDeleteI think using concrete bricks or any other bricks should be much easier and cost effective (time&labor) than ramming old tires.
ReplyDeleteYou lose the thermal mass though.
ReplyDeleteFor someone who has to deal with regular codes, getting the thing in is the battle.
If concrete means they like it better, the thermal mass, to me, is a small loss.
(Especially when there are countless earth covered structures using the same window/double glass interior/sun passive heating concepts successfully.)
Another thing about it, you are up and going pretty fast.
Spray coating or plastic wrap is up in the air as to which is better, but both are very quick.
There is more risk with concrete for radon, but the tires, even if coated, have NASTY stuff in them. (albeit in tiny amounts)
(Mine will be concrete.)
Also, enclosing a huge boulder as a conversation piece in the proper sun will have similar effects thermal wise.
Go ahead with the 'earthship'...if you want a house filled with thousands of poisonous chemicals used in the manufacture of tires. OR...concrete just as thick. Same cost when accounting for time and labor and MASSIVELY stronger. And no nasty petro-chemical off -gassing for decades to come.
ReplyDeleteI wonder if it would be easier to just fill the tires with cob??
ReplyDeleteThe off gassing of the tires has concerned me. It doesn't seem healthy to have your living environment filled with old tires, has anyone done actual research on this ?
ReplyDeleteI've looked into this extensively and all I could find is basically a general, "We don't know." Here's a perspective on the issue from a source outside the EB which
DeleteI found particularly helpful:
http://hackingtheearthship.blogspot.com/2015/01/tire-off-gassing-research.html
When I build my earthship, I will opt for the brick and mortar method - it may be more expensive, but there's basically no such thing as too expensive when it comes to preserving your health.
Tire off gassing should be finished within 20,000 miles. The thought is to make use of waste. A radon inspection should be done of job site. Ways to automate packing of tires to increase production needed. Seen a couple of videos. One guy in New Zealand does it all by himself with a backhoe and jumping jack with special foot. He packs tire in central location using jumping jack and moves packed tire into position with special strap and backhoe. It's still work but I could easily see him doing 5 or 6 an hour.
ReplyDelete