Questions regarding building home using plastic bottles filled with sand.

Hello all you friendly and helpful Permies!

I am placing this inquiry under eathship, but I am not really sure this would be considered an earthship. Please forgive me if this is the wrong forum choice.

My husband and I were originally going to build an earthbag home, but even that, with just us two, would be very strenuous and probably more than we could handle. I had watched some videos on plastic bottle buildings (homes and schools, etc.) and this looks more doable for us. My husband is on board with the idea because it should be much easier on us physically; each bottle weighing approximately 2#. We will have no one to help us as family and friends are 1500+ miles from us.

In all the research I have done, I have found the following:

Use at least 500 mL bottles (we drink A LOT of bottled water and we will have no problem coming up with the bottles. We have already begun to save them.

Using either sand or soil and we decided to have sand trucked in to us because the weight bearing is stronger than just clay earth or combined clay/sand earth.

Use nylon twine and wrap bottles as you go and then also at the exposed neck area of bottle, web together.

Mortar the rows of the filled plastic bottles as you go.

Supposedly just about any roofing structure can be used. We have chosen a metal roof, but with a lean-to type structure.

Our building is only going to be 12' x 16' and we have decided to reinforce the corners with rebar and "L"-shaped bent metal every 4th row at the corners horizontally, again for strength and stability.

We will have a 7' wall on short side and either a 9' or 10' on high side of lean-to roof structure.

We will dig or have excavated a 10" trench approximately 3" wider on each side (total of 6") wider than bottle walls and will add rubble of large stones and gravel, and then start building up walls with the mortar and filled plastic bottles.

Now for my questions:

Is there any book out there with instructions/construction steps? I have looked at several websites that link to more information, but have been dead-ended with either broken links or no longer existing websites.

In the videos I have watched, they are using cement, or sand and cement mixed to mortar with and I am not sure what type of cement would be best and what ratio, if any, in a mix of sand and cement. Is type S cement or Portland cement what we would need to mortar and finish the exterior walls? If not, any suggestions?

We might like to stucco the exterior wall if that is preferred over just cement or cement/sand mix; however, my husband has fallen in love with cob and is thinking we could cob the exterior. We live in an arid climate (halfway between Williams, AZ and The Grand Canyon) where average rain/snowfall is only 9". There is a monsoon season July to September, but more wind and clouds than rain; however, one never knows from one year to the next. If we use flashing at bottom of wall on the exterior of cob, or use stone wall on exterior a foot or two up before cobbing exterior walls, do you think the cob is a good choice or should we just go with stucco on the exterior and we can then cob in the interior walls?

Is a bond seam beneath the roof a good idea even though the roof is not going to be large and we will have rafters, and if a bond seam is a good idea, do we use the same type of instructions for a bond seam as with an earthbag building, starting down about 2 layers from the roof?

Or, is post and beam construction better for support of a roof, versus bond seam?

Other pertinent information: My husband did construction a long, long time ago, for many years and he is familiar with weightbearing loads and all things constructed with lumber, but we are wanting to keep down the cost and pay as we go once we start.

Thank you very much for taking the time to look at my post, and hopefully being able to answer some of my questions, give advice, and/or point me to either a book on this matter that I could purchase or to a more informative website.

Margo

Knowing nothing about this doesn't prevent me from having an opinion...LOL.

If you are going to use cement on one side, the outside seems to be the logical place as it is rather impervious to weather, use the cob on the inside. Sure you don't get much rain but freak storms and bad luck happen!

Cool idea though, I have never heard of doing that but it certainly is a wonderful way of turning a problem into an opportunity!

buildings from plastic bottles

I don't know if you have see this site but they mention several different methods of construction with plastic bottles.

In it they also mention using concrete for the exterior coating.

I love your idea and I wish you lots of good luck with the project.

Redhawk

Thank you both, Michael and Bryant, for your encouragement. We thought it was a kind of a neat way to do it. Right now, I am filling plastic bottles with dirt and we are going to experiment with a fire pit. The foundation has been dug and filled in with stone and gravel. I have 100 of the 200 plastic bottles filled. We will use cement, I am thinking type S cement, for the mortar and finish of the walls of the fire pit. The fire pit experiment will help us with the learning curve for when we start our home, which we plan on actually starting the home building next spring.

I had not looked at that particular website, Bryant, but there was a lot of information on that link that I had already seen on other links. I will keep researching and maybe find answers. Otherwise, we may be pioneering our own way, mistakes and all. LOL.

Hi Margo,

First off, I have never built with bottles. I do however have experience that is similar.

I would recommend that you do not load the bottle walls structurally; I'd use a timber frame, but you could frame this conventionally since it sounds like your husband is proficient in this. Then you eliminate the need for a bond beam as the roof will rest on timbers or a top plate.

For mortar, the big box stores sell an OPC/sand/lime mortar mix. This should treat you well straight out of the bag.

Clay plaster will work great inside and out, but the clay will probably have a hard time bonding to the smooth surface of plastic bottles, so you'll probably want to make a thin slurry with your mortar mix and harl that to get the initial coating, then clay plaster and I suggest a lime wash on at least the exterior. It's best to protect the bottom few feet of the wall with stone or similar.

Rubble trench foundations are wonderful when built well, but you might want to pour a short stem wall of pumicecrete on top of the rubble to ensure maximum stability and give you a good place to hang stone from.

All Blessings,
Bill

Bill Bradbury wrote:Hi Margo,

First off, I have never built with bottles. I do however have experience that is similar.

I would recommend that you do not load the bottle walls structurally; I'd use a timber frame, but you could frame this conventionally since it sounds like your husband is proficient in this. Then you eliminate the need for a bond beam as the roof will rest on timbers or a top plate.

For mortar, the big box stores sell an OPC/sand/lime mortar mix. This should treat you well straight out of the bag.

Clay plaster will work great inside and out, but the clay will probably have a hard time bonding to the smooth surface of plastic bottles, so you'll probably want to make a thin slurry with your mortar mix and harl that to get the initial coating, then clay plaster and I suggest a lime wash on at least the exterior. It's best to protect the bottom few feet of the wall with stone or similar.

Rubble trench foundations are wonderful when built well, but you might want to pour a short stem wall of pumicecrete on top of the rubble to ensure maximum stability and give you a good place to hang stone from.

All Blessings,
Bill

Thank you, Bill, for your input and suggestions. I will pass these on to my husband, since it will make more sense to him than to me, for the most part.

We see a lot of pumice rock in our area, which looks like a porous lava-type rock, more brown than black. Many people use that type of rock in their driveways and walkways, around their homes, etc. We have lots of rock in our soil, large to small, which makes digging very difficult sometimes.

Do you know of a specific brand name of the OPC/sand/lime mortar mix? (That is if it is allowed to state on the forum). My husband likes to research products well, online first. He will love your comments about using a timber frame as he knows what he is doing with lumber. He hasn't dealt too much with foundations and/or cement other than small jobs; meaning nothing to hold up a building. He always did framework, roofing, siding, interior, even plumbing and electrical, just nothing foundation-wise. In the past, he had built large workshops on pressure-treated posts 3' into the ground, but that was back in Missouri where the holes were much easier to dig. Here we find rock everywhere.

Since the building will be small, he has talked about wanting to place it on pressure-treated 4x4 skid runners, either on gravel or concrete blocks. However, with the weight of the walls and cob, clay, or cement with the thickness of the walls, he has no experience with that and we just aren't sure about placing all that weight on skid runners.

Thanks again for your input and suggestions.

Margo

http://www.inspirationgreen.com/plastic-bottle-schools.html


Since you have lots of porous lava rock (Scoria) out there, and have already settled on trucking in fill, have you considered hauling in some (presumably affordable in your area since people use it in their driveways) 3/4" minus screened Scoria as a lightweight earthbag fill? Scoriabags are about 35-40lbs (depending on your local Scoria composition and fill rates). A full 5 gallon bucket of screened scoria is no more than 20lbs. It's a pretty quick, durable, and  (when local) cheap method...

I am very happy working with and living in Scoria bag cconstruction. No complaints. No wetting or mixing fill, carries easily, tamps easily, courses don't settle, very solid and thick for comfort, since it's mineral it doesn't burn or rot or mold, has good insulation, and once plastered no drafts, insects, mice, termites, etc.... A couple fit dudes could lay all the scoriabags for that size building in a couple days. Bags would fill quicker than a bottle, and create much more wall quicker.

I second a rubble trench or Scoria trench or (mostly) Scoriabag trench

That is all said as a Scoriabag enthusiast since it's local for you. But regarding reusing the bottles, I'd personally think more in terms of ferrocementing empty bottles, quicker and insulative.
http://www.mycoolbin.com/2016/04/22/plastic-bottle-village-recycles-pet-bottles-build-houses/
Or Patti Stouter did a plastic bottle thing in hyperadobe or hyper-wattle or long tubes of raschel mesh.
Or could be pinned on either/both side with small diameter rounds, or post and beam infill, or ferrocemented with $20 cattle panels and stucco wire and stucco--all would create a quick insulative and strong bottle wall...

The construction method you outline is very similar to cordwood construction. I would suggest you look at some examples to see how they mortar, tuck and point, and otherwise construct walls in those homes. Much of what they've done will apply.

Here's a link to get you started: https://cordwoodconstruction.wordpress.com/2013/05/08/cordwood-castle-in-maine/

I'd suggest looking at the toxicity of the plastic (s) in this environment, there is alot of controversy around drinking water leaching. If I could not find proven test as in IAQ by several pros sources, I would not chance my health nor respiratory track to recycling.

Thanks for the ideas Christopher Steen.  I will discuss with my husband.  We originally thought about earthbags but then decided to go with the plastic bottles filled with dirt, for two reasons:  Lighter weight and also we wouldn't have to worry about clay to sand ratio, could just fill with sand.  I never thought about scoria in the earthbags.  I have been to the website http://www.inspirationgreen.com/plastic-bottle-schools.html already, but have not been to the website http://www.mycoolbin.com/2016/04/22/plastic-bottle-village-recycles-pet-bottles-build-houses/ and so I will check that out.

Thank you Chris Wells for the website link https://cordwoodconstruction.wordpress.com/2013/05/08/cordwood-castle-in-maine/
I will check it out for the information regarding the mortar, tuck and point, and construction examples.

I appreciate both of you for you insight and suggestions as well as pointing me to some good ideas and websites.

Margo

Terry Ruth wrote:I'd suggest looking at the toxicity of the plastic (s) in this environment, there is alot of controversy around drinking water leaching. If I could not find proven test as in IAQ by several pros sources, I would not chance my health nor respiratory track to recycling.

Oh my goodness!  I have been drinking bottled water for a couple years now.  I used to drink from a Brita water pitcher, but now drink from the bottles.  I am a diabetic and have to have filtered water for my kidneys sake.  I doubt I could get my husband to give up bottled water now that he drinks almost as much as me.  We go through anywhere from 48 to 72 bottles per week between the two of us.  We do keep it stored out of sunlight if what you are talking about is the plastic leeching into the water from that.  Otherwise, I guess I hadn't heard of harmful effects from water bottles, soda bottles, Gatorade bottles, etc.

But thank you for your input; I do appreciate it.

Margo

Margo Apel wrote:

Terry Ruth wrote:I'd suggest looking at the toxicity of the plastic (s) in this environment, there is alot of controversy around drinking water leaching. If I could not find proven test as in IAQ by several pros sources, I would not chance my health nor respiratory track to recycling.

Oh my goodness!  I have been drinking bottled water for a couple years now.  I used to drink from a Brita water pitcher, but now drink from the bottles.  I am a diabetic and have to have filtered water for my kidneys sake.  I doubt I could get my husband to give up bottled water now that he drinks almost as much as me.  We go through anywhere from 48 to 72 bottles per week between the two of us.  We do keep it stored out of sunlight if what you are talking about is the plastic leeching into the water from that.  Otherwise, I guess I hadn't heard of harmful effects from water bottles, soda bottles, Gatorade bottles, etc.

But thank you for your input; I do appreciate it.

Margo

Put the water filled drinking aside and forget about it since it is irrelevant, but worth a look see, and all the family's of plastics used in that industry and the quality control. The subject is filling them with sand in a building environment. In the building community, one does not have to look far to see the issues high toxicity plastic vapor barriers cause. Sand conducts heat to the plastic boundaries, nor is good at managing vapor solely if it gets in the bottle. Add UV and vapor/heat/dew exposure, like some PEX most have no UV protection and corrode on the way to the job site, or PVC, or HDPE, LDPE, or or other reactive polys like PET that leach BPA, along with various manufacturing processes and non-conclusive testing. No manufactured said mating to sand and these environments is safe. Just saying! There have been plenty of products used in construction we discover years later that cause health issues and the list is growing. That is what brings most folks to this site to look for natural non man made materials. Good luck with it

One liter bottles are about 3" diameter, so 16 of them are needed per square foot of wall. 12' x 16' x 8' average height = 1536 square feet x 16 = 24,576 bottles. At 72 bottles a week it would take you 341 weeks or well over six years to collect the bottles you would need. If you use 500ml bottles, the quantities increase.

Have you done the bottle-filling experiment yet? How long did it take to fill a hundred bottles with sand? Sand will have decent compressive strength when contained, but if bottles at the bottom of the wall start to fail, the sand in them will happily flow out. Drinking water bottles that I am familiar with are made from the thinnest material that will stand up to shipping in cartons and holding to drink from once.

I don't think those bottles buried in a cob plastered wall would be a measurable health hazard in your case, but I don't know for sure. I do believe that scoria-filled earthbags, since you say the material is abundant near you, would be a much faster method than mortaring tens of thousands of individual bottles after filling each one with sand.

A consideration we haven't gotten into yet is your climate. How cold does it get at night, summer and winter? What are the average temperatures? Also, you mention that you have a lot of rocks in your soil, but how much clay is there? Do you have mostly sand, or a layer of clay at some location, or...?

I think what Glenn is referring to is burst pressures we consider in Engineering in pressurized tubing, I see as tension capable of the threads (which is not a vapor or water seal when broken) as the weak link. I have not given this much thought, too much labor and risk for low performance for me but Glenn makes a good point once bottom rows fail what a mess!  In my mind, the greatest risk for microbes is at the plastic interface, add an abrasive sandpaper that fails the plastic and who knows what can happen. I would not assume organisms in COB as anti-fungi or bacteria, or a safe house for microbials that will not leach to IAQ. I'm not aware of any building material that does that.

Agree, scoria with the a strong natural bag makes much more sense.

Thank you Terry and Glenn for your input.  I have discussed all of the scenarios mentioned with my husband and we will go ahead and finish the fire pit since we only need 40 more bottles to complete this small experimental job.  However, we have decided to NOT use plastic bottles in construction of home because of the safety issues, weightbearing possible issues [failure], and the time in which it would take.  We are working on a two-year plan, with actual building construction to start next spring.  

I am glad that I asked for input and advice from all of you Permies on this forum.  We are very open-minded and consider all options open to us.  We were kind of "in love" with the idea of plastic bottles, but wanted to know other people's opinions to help us think it all through.  It seems like maybe the scoria earthbag buiding is the way to go.  

This summer, so far, has been hotter than usual with highs at 100 a few days and mid to high 90's several days.  Records have been broken with 93 being the previous record hottest June day ever here.  The coldest days ever recorded in this area have been in January and February at 14 below and 19 below, respectively.  The average lows are single digits to zero in these same months.  We were looking for thermal mass because of the winters and, now, also because the summer can be very hot, as well.  I have researched some on the scoria and find that the insulative values are quite good.  I haven't priced it yet.  We are in the figuring out how many bags we will need stage, and think it will be less than 1000, but will order 1000.  Next, I will check into the scoria pricing with delivery and try to come up with a fair estimate as to how much of that will need to be delivered.  

Thanks to all of you for helping me with my questions and giving me more information than what was asked for.  In my naivite, the questions that I didn't ask with your answers, have been a tremendous learning experience for me and I truly appreciate it.  Sometimes one does not know what questions to ask and, thanks to you great Permies, I was helped with answers to questions I hadn't thought of asking.  That kind of help is what makes this forum so great!

Margo