Building a Roof for my Earthbag Home

Hi Permie friends.
I am still a couple years off from building my Earthbag and Adobe home in Arizona. I am in the process of drawing up plans so I can make a rough calculation of how much/how long I will have to save. I am trying to build my house on the cheap so that I have money left over in case of emergency or unexpected costs.

So far the actual structure of the house can be built pretty cheap even if I have to have dirt delivered for my earthbags. The biggest expense I have come to is the roof. I plan on doing water catchment and since I will be in the desert every drop counts. I think doing a metal  shed type roof will be easiest as a first time builder but beams and trusses and plywood add up in cost FAST.

I guess my question is: does anyone have any ideas on ways to cut cost building (especially the roof) while still keeping structural integrity?

Hi Monica, how big is your building going to be?

A couple things come to mind.  Search for My Little Homestead on YouTube and you'll find a family that has built a half a dozen earth bag buildings and put a variety of roofs on them.  You might get some ideas from them...

If I was building an earthbag house, first it would be round or ameba shaped.  Then I'd put a reciprocal frame roof on it.  Look up Tony Wrench and you'll see some YouTube videos of a sweet looking roof that is made with logs and scrap wood.  I think he generally does living roofs which wouldn't work as well to collect rainwater.  But maybe a frame/structure like his and top it with Ondura like the My Little Homestead people?

First of all, I love my little homestead. I have watched their videos of building and they have given me a lot of ideas. The house I am looking to build is about 400-500 square feet. An all in one room being my main living space and a smallish bedroom and bathroom. I think I am just going for squared building style as it will be a lot less complicated than the round rooms, even though they look so cool. I am trying to make building as simple as possible with only a few design elements.

I am also looking at doing natural materials for the building as possible and not using much cement. The cost of beams and treated lumber for the roof is expensive and I don't think I'll have much access to logs and timber in the desert. I have thought about domed roof but then water collection wouldn't be possible.

I think the native peoples used to live in wigwams in the desert.  Sometimes I think they were half-buried. The roofs were made of some big wood poles, and covered with lighter material such as bark or straw. Complicated looking to build,  but excellent for keeping your temperature comfortable and the sun off your back.  Obviously, doesn't fit in to today's building code as far as I can tell.

I am looking to build in an area with no building code. And making most of the house underground would work too since i could just put the dug out dirt in the bags. But I need a good clean surface to collect the water from. I may just try to find a discount store for some metal roofing. The problem I keep running into tho is just the beams or treated lumber to hold up the roof are expensive. Maybe i can find a discount on lumber too.

Metal is loud and transfers heat real well, so you'll need to drink more if you get a metal roof ( in theory)... but it is a catch 22. What about pallets? Not many trees there either,  I'm guessing? I cheat on pricing by going to the fencing section of the lumber yard.  I find the cedar and treated lumber there much more affordable. I do a lot with cedar fence pickets. And,  also,  in an arid region especially,  I'd think that once you seperate the wood off the earth,  you should be able to use untreated.  

Monica Stuntz wrote:I think I am just going for squared building style as it will be a lot less complicated than the round rooms.

I believe that there are structural reasons for earthbag buildings being round, so you might want to check up on that.  

Google "Cement Latex Roof"  and "George Nez".  I am going to make another poultry shelter in the bird's yard this summer and use this for the roof.

Interesting reading:  http://www.academia.edu/22223899/Latex_Concrete_Papercrete_Roof_Flying_Concrete_we_think_we_have_found_the_way_we_will_do_roofs_from_now_on

And I may experiment with this rapid set cement and cloth idea for one outside wall.  Yeah, cement isn't very permie or environmentally cool, but I am really short on money and time and have a lot to get done this summer.  This might get the extra room I need to keep some of my birds from bullying.   Bob Campbell, the guy who made the video, says that it held up fine being outside over winter.

You could also look into glass bottle house construction too for square walls that are strong and cheap.

Amit Enventres wrote: What about pallets? Not many trees there either,  I'm guessing? I cheat on pricing by going to the fencing section of the lumber yard.  I find the cedar and treated lumber there much more affordable.

I have thought about getting a bunch of free pallets off of Craigslist, there are tons, and using them for the structure of interior walls for my bathroom and plastering over them.  I suppose I could use them and some other cheap cuts underneath my corrugated roofing as well. The support beams/ trusses might just be something I don't want to cheap out on. Plus if I use pallets on the roof I can probably plaster over them like my interior walls.

Amit Enventres wrote: You could also look into glass bottle house construction too for square walls that are strong and cheap.

I have defiantly thought about using bottle walls for parts of my house and outdoor structures like an outdoor shower I plan on building eventually.

Dakota Brown wrote: I believe that there are structural reasons for earthbag buildings being round, so you might want to check up on that.  

Google "Cement Latex Roof"  and "George Nez".  I am going to make another poultry shelter in the bird's yard this summer and use this for the roof.

And I may experiment with this rapid set cement and cloth idea for one outside wall.  Yeah, cement isn't very permie or environmentally cool, but I am really short on money and time and have a lot to get done this summer.  This might get the extra room I need to keep some of my birds from bullying.   Bob Campbell, the guy who made the video, says that it held up fine being outside over winter.

As far as the square/ rectangular building goes, I have definitely seen people build earthbag homes with this style before. Some of them have buttresses to support the walls and some don't. My building layout is definitely not set in stone.

I am also interested in other alternative roofing techniques. This may actually work really well with the acrylic concrete method instead of metal roofing. At first i thought it would be super heavy to have a concrete roof, to me it sounds like it would be heavier than plywood and tin. But after reading about it, It's lighter and supports itself. I dont mind using cement if it is cheaper. I know this is not super eco of me, but neither is timber and metal I guess.

If watch catchment is a big factor, I worry you will have trouble catching clean water. It gets very windy and dusty in Arizona. I know most systems have a runoff to get the first few gallons of dirty water but that may pose issues.  What if you built a super cheap water filtration system. That would allow you  more freedom in design and materials for your roof and not have to waste so much run off. I was thinking of something super cheap like this for the filter.

Krista Marie Schaus wrote:If watch catchment is a big factor, I worry you will have trouble catching clean water. It gets very windy and dusty in Arizona. I know most systems have a runoff to get the first few gallons of dirty water but that may pose issues.  What if you built a super cheap water filtration system.

I do plan on using a good filtration system for any water i intend on drinking and cooking with. I have watched some water catchment videos from some youtubers out of Arizona and they say that the dust that gets in their systems from the roof usually settles on the bottom of their main water tank . So as long as they leave room for the dust to settle underneath the spout they have pretty clear water unless they shower during a rain storm. Then once a year they clean the settled dust out of the bottom of their tank after pumping the water into their overflow system.



Now I don't plan on having a system this big but it has given me some good ideas for my own.

You could still collect water from the domed roof. As you complete you dome house, dig a trench all round the house say 1.5feet deep and two feet wide, put some tarpaulin lining at the bottom and then fill with aggregate/ chip stone. This will work like what they call French drain. From this trench create another trench same depth with trench sloping 1% out which then you will install a pipe that will transfer the water collected from the trench to the underground tank that you would also have to construct. The tank can be at any distance provided you have your slop to drive the water to the tank. The tank should have a sump and overall floor sloping towards the sump which will collect the dirt if any. The water should clear once collected and then install your solar pump, and can do whatever you want there because you would be sorted with water issue.

I've experimented with this latex cement roofing idea a bit on a small scale -various mixes of flyscreen/sikatex or decent exterior paint/portland/sand ala George Nez. So far holding up very well as a small shed roof, and sealing up irregular holes in a cabin and chicken house and to patch house underpinning.

I'm surprised I've not been able to find any example of anyone combining this system with a reciprocal roof.  Since the big drawback of them seems to their irregular shape, a freeform roofing option like latex cement seems like a good match.  And though many folks are opposed to cement as a building material on ecological grounds, it certainly seems like an appropriate use of a high embodied energy material in that it will likely last a long time and be easily repairable.  Going to attempt our first larger scale project with it in the spring.  

Dakota Brown wrote:

Google "Cement Latex Roof"  and "George Nez".  I am going to make another poultry shelter in the bird's yard this summer and use this for the roof.

Interesting reading:  http://www.academia.edu/22223899/Latex_Concrete_Papercrete_Roof_Flying_Concrete_we_think_we_have_found_the_way_we_will_do_roofs_from_now_on

And I may experiment with this rapid set cement and cloth idea for one outside wall.  Yeah, cement isn't very permie or environmentally cool, but I am really short on money and time and have a lot to get done this summer.  This might get the extra room I need to keep some of my birds from bullying.   Bob Campbell, the guy who made the video, says that it held up fine being outside over winter.

There is a very informative and funny YouTube channel called "My Little Homestead" that covers earth bag construction and roofing. It is also about a real cool family that all works together.These people are phenomenal and I highly recommend their channel!