Efficient Earth-Sheltered Homes

This house in Tempe, Arizona, uses earth-sheltered construction methods to help decrease cooling costs. | Photo by Pamm McFadden

This house in Tempe, Arizona, uses earth-sheltered construction methods to help decrease cooling costs. | Photo by Pamm McFadden


“If you are looking for a home with energy-efficient features that will provide a comfortable, tranquil, weather-resistant dwelling, an earth-sheltered house could be right for you.

There are two basic types of earth-sheltered house designs—underground and bermed.

Underground Earth-Sheltered Homes
When an entire earth-sheltered house is built below grade or completely underground, it’s called an underground structure. An atrium or courtyard design can accommodate an underground house and still provide an open feeling. Such a house is built completely below ground on a flat site, and the major living spaces surround a central outdoor courtyard. The windows and glass doors that are on the exposed walls facing the atrium provide light, solar heat, outside views, and access via a stairway from the ground level.

The atrium design is hardly visible from ground level, creates a private outdoor space, and provides good protection from winter winds. This design is ideal for building sites without scenic exterior views, in dense developments, and on sites in noisy areas. Passive solar gain—heat obtained through windows—is likely to be limited because of the position of the home’s windows, and courtyard drainage and snow removal should be carefully thought through during design.

Bermed Earth-Sheltered Homes
A bermed house may be built above grade or partially below grade, with earth covering one or more walls. An “elevational” bermed design exposes one elevation or face of the house and covers the other sides—and sometimes the roof—with earth to protect and insulate the house.

The exposed front of the house, usually facing south, allows the sun to light and heat the interior. The floor plan is arranged so common areas and bedrooms share light and heat from the southern exposure. This can be the least expensive and simplest way to build an earth-sheltered structure. Strategically placed skylights can ensure adequate ventilation and daylight in the northern portions of the house.
In a penetrational bermed design, earth covers the entire house, except where there are windows and doors. The house is usually built at ground level, and earth is built up (or bermed) around and on top of it. This design allows cross-ventilation and access to natural light from more than one side of the house.”

More at Energy.gov

Efficient Earth-Sheltered Homes is a post from: Natural Building Blog

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Larry’s Earthbag House

Three-story earthbag house under construction near Bozeman, Montana

Three-story earthbag house under construction near Bozeman, Montana


“Across the hill from my cabin live Larry and Lea Van Arsdale. They are building a BIG earthbag house thirty feet in diameter and thirty feet high! They started a year ago and are still working on it, but they’ve been living in it since last fall. So far it’s two stories high and they plan on building the third story next summer. Right now they are scrambling to “cobb” the rest of the exterior before winter. That means applying the cob, (earth plaster) or adobe, to the bags which make up the wall.

In the picture you can see exposed earthbags on the right. Just to the left of that is dark area that has been freshly cobbed. The larger gray area is what the cobb looks like dry, and the white area to the left has been coated with a mixture of lime and horse manure(!) to seal in the cob.

The size of the house is deceptive. When you walk in the front door (around to the left) you walk down about 5 feet to the floor, so much of the house is underground.
The earthbags have to be covered with tarps until they are cobbed, in order to protect them from the sun. Rain won’t hurt them, but in the sun the bags will disintegrate in about three months!

Larry has been my source of information for the building process and gives me all kinds of advice and hints to make things work better. They live there full time and are off the grid, using solar and generator with big battery packs. The house is wonderfully cool in summer and warm in winter. So anyone who comes out to help with my house will get a tour of Larry’s!”

Kents Cabin blog

Larry’s Earthbag House is a post from: Natural Building Blog

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Building with Earthbags and Adobe/Cob

Our house mid-construction. Earthbags on bottom, bamboo frames for wattle-and-daub on top.

Our house mid-construction. Earthbags on bottom, bamboo frames for wattle-and-daub on top.


“As a little girl, and a young woman, I always dreamed of building my own house someday but I never had a specific desire for it. I knew that the right house would come along at the right time and with the right partner, and we’d build something that fit our needs, together.

However, I never ever dreamed it would be a dirt house.

Well, the right time and the right partner came along and at the beginning of this year Andy and I broke ground on our house. And in the six months since, our home has evolved into something more beautiful and cozy than I could have imagined.

Did I mention it was made out of dirt?

We wanted our house to be both ecological and economical while still being beautiful and meeting all of our needs and after a lot of research we decided that an earthbag house was right up that alley.

What are earthbags?
Earthbags are basically feed sacks filled with earth, pounded into bricks and covered in adobe/cob. We bought the feedsacks on a roll (like one big tube instead of individual sacks) and filled them with the dirt we removed when making our home site flat.

The second story is actually wattle-and-daub. Wattle-and-daub is the technique used to apply the adobe/cob to framed walls, just like you would apply drywall to wall frames. Except, no joke, it was cheaper for us to pay 8 guys to mix dirt and pack it into the frames and then go over it three times with different finishes than it was for us to buy drywall and have them nail it up.”

Gypsies and Globetrotters
Note: This article is inspiring and the house is very nice, however, there are some small errors in the article. For instance, they say the walls are 5” thick when in actuality they’re probably 15” thick. And their definitions of adobe and cob aren’t quite right. Adobe is sun dried earth, not baked. What they calling cob, most natural builders call earthen plaster.

Building with Earthbags and Adobe/Cob is a post from: Natural Building Blog

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Ferrocement Rainscreen for Earthbag Domes

A ferrocement rainscreen would look much like this drawing.

A ferrocement rainscreen would look much like this drawing.


Domes evolved in deserts, so we recommend extra protection for snowy/wet climates. There are two main approaches: 1. Build a roofed dome. Search our Projects pages at Earthbag Building.com to see several examples. 2. Build a ferrocement rainscreen on the exterior of the dome. The rainscreen is basically an outer cement shell that’s built on top of the dome with about 1″ space between that allows any water that gets through to escape.

Directions: Add 1/4″ rebar pins 12″ apart on the exterior. Leave about 2” of rebar protruding above the surface. Then bend over the rebar at 90 degrees so about 1” is left protruding. Attach weep screed along the bottom. Plaster the dome before proceeding and add a moisture barrier such as elastomeric paint because cement plaster absorbs moisture. Tie plaster mesh or similar mesh to the rebar with tie wire and then cover with 2-3 coats of cement plaster.

Weep screed: This stucco flashing supports the stucco and allows water to drain out of the wall. Use a screened vent on top of the rainscreen that allows moist air to escape but keeps pests out.

Image source: First Choice Inspect.com

Ferrocement Rainscreen for Earthbag Domes is a post from: Natural Building Blog

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