John Eklund

I was wondering if anyone had any information on Rammed Earth construction in Huerfano County. I will be purchasing land there soon and would like to construct some Rammed Earth structures on the property.

Thanks,
John

John Namazi wrote:It probably varies from place to place, but some areas require at least 2 forms of egress from every bedroom or perhaps every room of livable space. So if you have rooms in the back with no windows the design would fail inspection. I think that's one of the common reasons earthships are laid out the way they are, with no doorway between bedrooms and the main living space so they aren't counted as separate rooms requiring windows you can crawl out of in case of a fire. Perhaps 2 bedrooms with a shared bathroom between them would provide that "second door" to escape a particular bedroom, running to the other and then out? I'm not at all sure how that works, but I think it should be considered since that impacts other parts of the design.

Thanks for bringing up this point. I did some quick research into this and found a few loopholes that many areas are adding to their building code, specifically due to the increase in popularity of the "buried home". Many places will now make an exception to the rule as long as you use specific materials to guarantee "fireproofing" of the room in question. Since I use a wooden roof, my rooms would still fail this, however, since I opted for 10-ft walls, I could always include a drop ceiling with fireproof ceiling tiles, which should satisfy the code requirements for areas that do include the exception.

Another route I may look into would be some form of "roof exit". As long as the exit includes a permanent ladder and does not require a key or tools to open, it will fit the criteria (even though the only things capable of burning in the room would be roof and furniture, this will still satisfy the code requirements). Normally, "roof exits" would not fit the criteria as a means of egress, but that is based on the fact that most roof exits exist on tall buildings in which the roof is not at ground level so the occupants would still need to re-enter the building to make it safely to ground level. With the roof of my design being at ground level on the north end, a vertical exit to the roof is also an exit to the outside in which does not require re-entry to get to the ground level. One of my original concepts (the double roof design) was actually going to include exits, to the north end of the building, in the attics. Not sure if those exits would have been counted as exits for the bedroom below though, but with the roof design above, I could simply add in skylights, that open from the inside, with the addition of some sort of pull-down ladder. This will then provide additional light as well as the exit required for code.

I'm liking the skylight exit and plan to add it to the design now.

Thanks,
John

Edit: Just did a quick search on "skylight exits" and many websites are calling them "Egress Skylights" which are designed specifically to meet the "2 means of egress" code. Can get these windows for anywhere between $400 and $1,000 each, while the average cost of adding a drop-ceiling would be $1,250 per room (I love it when savings is also combined with functionality and even aesthetics).

I thought I was done with the roof, but I decided to try out a design that may or may not work. Please let me know if this design is feasible.


Went back to the original Earthship-style roof concept. I used flat roof trusses of varying height to create the slope then connected them with 2"x6"x10' lumber similar to the large 70' roof. I lose most of the attic, but will still be able to run utilities through it. The area above the entry corridor will have heights between 4'6" and 5'6", with each adjacent area losing 1 additional foot as you move north.


I also added the greenhouse planters. You can see that each planter gains depth the further they are from the center. This is to guarantee drainage, which will end at the "treated greywater tank" which is not shown. From there, it will be pressurized for use by the toilets.

Brian Cooper wrote:That's a question of material science, you might need steel for that kind of span. Not to fret, though, bigger roofs than this are built every day, even if not by your local nailbanger.

Maybe it's time to check in with a Amish barn-builder if you want to stay with wooden framing.

Found a few businesses that make up to 80-foot trusses, so I got 3 quotes for a 70-foot truss and they are about $500 each (rounding up from highest quote). I did not get any quote on shipping and I'd imagine that would be pretty expensive. To build them myself would cost $400 each in lumber and hardware. Then I will need many 2x6s (over 500 of them) to run between the trusses for both the roof and the ceiling inside the house. If all trusses are built myself, this will run over $7,000 for just the framing of the roof (not including other hardware, like nails for the 2x6s). Cost to buy the trusses and get them shipped out will add between $1,000 and $2,000 more. Going to update my price sheet with these figures as this is the route my design is taking. I am happy with this roof now and can now move onto the plumbing of the design.


Very large roof, but should solve all the problems that were previously mentioned. Thank you everyone who has helped make this evolve into a better design.


Inside view. You can see all the 2x6s that need to be used.

Thanks,
John

Brian Cooper wrote:Until we've perfected the household-sized 1.21 gigawatt Mr. Fusion generator I'd prefer to stay away from engineering exterior electric radiant heat $$ into a roof design. Ask my wife how much I hate to heat the outdoors.
Over the long haul it might be less expensive to source full 68-foot trusses (or 58 footers running the other way, tying into the greenhouse roof.)

This is an interesting exercise - I don't often run into spans this large in single-unit residential construction. Maybe we could crib from a commercial application. There's no doubt that this is a big ol' roof.

I do plan for 2x Tesla PowerWalls for 28-kWh @48V energy storage, but no time travelling with that, haha. I could most likely get away with heating only that center valley only on snowy days, but am still looking for a more permanent, easier to maintain, less risky solution.

Any idea how much roof trusses that large would cost? Main reason I went with 2 sets of trusses was because I wasn't able to find any pricing on anything larger than 40-foot trusses so decided to go with what I could easily find.

Brian Cooper wrote:There's no benefit to an upside-down truss. If you want a flat-bottomed slope there just (!?) nail lumber between the main trusses. (sorry, still flinching.)

Darn, was a quick thought, but figured it wouldn't be really reasonable. I guess nailing the lumber between the trusses would accomplish the same thing for much cheaper anyways.

That center valley still makes me flinch too. I hope all will be fine if I take extra care waterproofing it and add in the strip of radiant heating to melt the snow in the winter. Depending on how cheap I can get the electric radiant heating in bulk, I may even setup the entire roof and driveway to be heated (I used to do sales/marketing for ThermoSoft years ago).

john mcginnis wrote:" Walls are now perfectly straight and square like a modern house."

Might want to check that. If you look at a typical earthship design the bearing walls facing the earth berm are mostly curved. % of flat is very low. You need to account for bearing load + hydrostatic pressure against the wall surface. Curved surfaces have better resistance to shearing loads. Its why most dams are curved.

Shed roofs are easier to construct and maintain. Every hip and valley you create costs more and adds to the maintenance complexity.

The idea of the tanks around the structure is reasonably novel.

Good luck!

This design uses Rammed Earth Walls, which require 5% to 10% cement mixed in with the dirt in which solves any problem with load-bearing or pressure. This technique has been used for thousands of years and many thousand-year-old structures still stand today. The main reason for the curved-nature of the walls in an Earthship is due to using tires (creating a perfect square with circles will result in a loss in structural integrity, but creating a perfect square with rectangular segments results in added structural integrity, e.g. modern house framing) as well as those tires being packed with only dirt, no cement.

As for the roof, there are many reasons for its current design. Clear span, attic space, common building materials, etc. Find me some 50' beams for cheap and I would gladly make it a single slope. Check any lumber yard for roof trusses and they are cheap due to being mass-produced with consistent specifications.

Edit: Some examples of Ancient Rammed Earth Structures.

Brian Cooper wrote:Are you planning a passage through the center wall to get to the third bedroom and the interior door of the garage? Also, am I correct in thinking that the center wall is also a plumbing wall, with water supplies and drainage from the kitchen and baths? What are your plans for positioning the water heater(s)? Point-of-use or central?

If your room layout is finalized, do you have a ductwork plan? I've witnessed horrible blowouts between tradesmen where lumber, duct, wire, and pipe conflict. It ain't pretty.

Yeah, a passage to get through to the bedroom and garage is planned. Not sure if I posted the floor-plan here, so I will also include that at the bottom of this post.

I plan for the plumbing to run from the pressurized tanks in the garage up into the attic and then run down that center wall to the points where it will be needed. Conduit and plumbing will be built into the walls and run up into the attic. Duct-work is also being planned for and I will make sure there will be no conflicts. I also plan to use on-demand water heaters at point-of-use supplemented with solar heated water (been looking into how this is accomplished). All drainage will run under the floor next to the center wall (didn't want to deal with a horizontal pipe running through the wall sections).

Here is the floor-plan and side view.

The additional floor-plan is simply the same design, but flipped to have the garage on the opposite side. The red sections of the wall indicate where to start the Rammed Earth Walls and then the arrows indicate which direction to continue the wall. Light-red sections don't fit the template for the form I designed and may be replaced with standard framing. It is hard to see, but conduit locations are marked, both for electrical and ethernet. The 2 rectangles in the garage represent very large vehicles (6'9" x 18'8" each) and the 2 squares in the rooms represent access points to the attics. Purple indicates a place to sit (beds, sofas, chairs, etc.), orange is for counter/table surface area and the blue-green color represents utilities/appliances. Green for plants, pink for insulation, blue for rainwater and white for distilled water (also for plumbing/hvac, but the white in the tanks is distilled water).

Edit: Forgot to mention the yellow area with the sofa on it. This is raised up about 2 feet and includes a ramp to access it. I did this to create theater-style seating and allow for additional storage underneath. I chose to go with a ramp to keep the entire house wheelchair friendly, with all doors being 3-ft wide and 8-ft tall as well (I work part-time as a mover and I dread all small entryways).

Wanted to also quickly mention that this floor-plan is not current. It still uses 3-ft thick outer walls with the insulation outside them and I have progressed to 4-ft thick outer walls with 6" of insulation built-in.

Just thought of a quick concept for controlling airflow and humidity within the greenhouse itself. Since my design utilizes 2 separate greenhouses, I was thinking of adding a small amount of duct-work to create a constant circulating airflow between the greenhouse. I would pump air out from one top corner and pump it back in through the opposite bottom corner and have identical duct-work in the other 2 corners. This way I can have one set of the ducts simply create a constant airflow, and the other set can have filters specifically for eliminating humidity and these will only be turned on if humidity is too high (plan to automate it with sensors). By doing this, I imagine the 2 greenhouses would regulate each other, not to mention all the added benefits of having the air circulated. Will have to experiment with this on a small scale.

Edit: Thought I would toss in the latest 3D model with the new roof design.


The center valley and the slope created with stucco. An idea also just popped into my head that I could possibly use upside-down roof trusses of decreasing length to create this slope. Will have to try designing this and will post a picture later to see if it is even possible or reasonable.


The roof comes directly up to the greenhouse now. This will not only help with drainage, but also makes it very easy to ventilate the greenhouses into the attic to use that heat inside the house during the winter.

Brian Cooper wrote:Your central wall is inside the building envelope, so an inspector would probably call it an interior wall - and would likely want a beefed-up footing under it for the load.

Yep, the central wall definitely has a good footing. It utilizes the same grade beam as the outer walls (figured I would treat it the same since it is load-bearing).

Brian Cooper wrote:On third thought, consider stopping the earthen wall short of full height and frame knee walls to support the trusses and make insulation room. Also see: raised-heel trusses.

Will have to look into this further and find a way to incorporate it.

Bernhard Haussler wrote:Hi John!
I am also interested in building an earthship but will be using gabions to create the mas. My location is near a river bed which is being mined for building sand and ther is a huge stockpile of reject material available [stone and pebble] I agree that the use of tyres is not "the" issue. However, your layout removes on of the rooms completely for the energy source - ie the solar facing greenhouse. And even more strangely, you have put a garage between the living area and the energy source. While tires are a matter of choice, the "row of rooms" is somewhat more fundamental to the whole concept and its likely success..

When it comes to thermal mass, the sun does not have to be shining on it for heat to be stored. Thermal mass is simply used to "stabilize" temperatures throughout the entire year. If I were to dig a tunnel going a mile deep (nowhere near sunlight), thermal mass will still apply and keep the temperatures steadily between 50 and 60 degrees Fahrenheit all year.

The concept of thermal mass was to limit the use of HVAC. In my design, that 70 degrees you keep constant inside the house, even through use of HVAC, will be stored inside the 4-ft thick walls to be used throughout the winter. In a standard modern house, with practically zero thermal mass, will waste every bit of HVAC used throughout the year.

In my opinion, and many opinions I read online from people who have tried living in Earthships, not having a thermal mass barrier between the house and the greenhouse only invites many problems. Humidity being the largest factor. This is why I include the separation and the use of attics. During the winter, let that heat be pumped into the duct-work that will already exist for central air so it can be properly filtered (dirt, pollen, etc. and humidity). All it takes is a duct fan to draw that air in from the greenhouse and the airflow will reverse when compared to the airflow during the summer.

Also, the airflow of a standard Earthship is not created due to the sun being able to "enter the house" or "heat the rooms". It is created due to temperature differences between your house, the greenhouse and the outside world. If the air is only given a few places and enter and a few places to exit, it will flow in the direction you want it to (even if it doesn't, it can be forced to with the help of a duct fan, still making it way more efficient than standard HVAC). My design still utilizes this airflow concept, it only differs in that I will have the air flow through the attic instead of directly through each room. From the attic I can better maintain the utilities involved and I can more efficiently heat and cool the entire house, making sure each room is given ample airflow.

As for the garage, due to the explanations provided above, it really doesn't matter that it sits between the greenhouse and the living area. In fact, the bedrooms being in the back of the house, where it is buried, was chosen on purpose due to the concept of thermal mass. These rooms will have the most stable temperatures when compared to the garage or kitchen and living room. By forcing the airflow through the attic and not through a series of rooms, I am now able to design this Earthship-type house with any floor-plan (you dream it and it can be done). I honestly think the original Earthship only utilizes the airflow in its current manner simply because they chose not to use roof trusses and do not have the option of utilizing an attic for ventilation purposes. Their roof was chosen for efficient rainwater collection which left many other aspects of the house inefficient.

-John