A Beginner’s Guide to Earthbag Homes Construction
Earthbag homes use simple and sustainable materials with several advantages over traditional building materials.
The prices of common building materials, such as lumber and sheetrock, have skyrocketed in recent years, which has caused a movement for homeowners and builders to look for alternative building methods.
In this article, you will learn what an earthbag home is, how to construct an earthbag house, the different types of house structures you can build out of earthbags, and in-depth answers to questions about earthbag construction.
Basics of Earthbag Homes
An earthbag house is a structure built with sandbags. Earthbag construction starts with using fill material found at the construction site. This fill material is composed of sand, dirt, clay, and gravel.
Earthbags are polypropylene bags that are waterproof and fireproof. These rugged bags can endure also endure heat, wind, and cold.
The earthbags are placed side by side, like bricks, to build vertical walls. Barbed wire is placed between each layer of earthbags to secure the earthbags from shifting.
Earthen plaster is then used on the structure to enhance the integrity of the building and give it that smooth, polished look. You can paint this plaster or leave it natural.
The earthbag building method is similar to masonry work, as the bags are staggered. You will need to plan everything out before building, including framing doors and windows.
Best Locations for Earthbag Homes
It is crucial to build earthbag housing in the appropriate climate. Not every region is suitable for an earthbag structure.
The best place for constructing an earthbag house is warm, dry climates. The rule of thumb is to build a thermal mass structure for warmer temperatures and an insulated structure for cooler climates.
An earthbag structure’s mass will assist in keeping the interior cool in the summers.
You do not want to construct an earthbag building in cold, wet climates. The natural materials inside the bags will never have a chance to dry out, which can cause swelling and heaving due to freezing temperatures.
Cold, wet climates also promote mildew and mold, which can eat away at the bags. If you build an earthbag home in a damp environment, ensure that your fill material is completely dry before filling your bags. You will also need to ensure proper drainage away from the structure.
The best climate to build an earthbag house is in a warm, dry location with mild temperature swings.
Benefits of an Earthbag Home
One of the best benefits of constructing earthbag buildings is that you can create any structure imaginable with various shapes, sizes, and floors.
One of the most popular structures is the earthbag dome. The dome is a circular dwelling with a cone on top. These dwellings are practically indestructible, and the shape is trendy.
More benefits of constructing an earthbag home are:
- Thermal mass insulation – the earthbags’ mass provides insulation to the house and keeps temperatures moderate during the winter and summer months.
- Dirt cheap construction – the cost of constructing an earthbag home is about 80% less than a standard home.
- Resistant to natural disasters – an earthbag house has innate structural integrity and is fireproof, waterproof, earthquake-proof, and even bullet-resistant.
- Sustainable building practice – earthbags use a limited amount of lumber, stone, and concrete making it one of the most sustainable methods of building.
- Unlimited design – Earthbag houses are known to be round and smooth, as the bags can be situated to make any shape imaginable.
Consider these important drawbacks before deciding if you want to use earthbag construction for your home.
Drawbacks of an Earthbag Home
One of the most significant drawbacks of earthbag construction is having the correct soil type to fill your earthbags. The fill must be a balance of clay, dirt, and sand. If your soil is too dense with clay, you can add crushed volcanic stone, rice hulls, or vermiculite.
If you need to amend your soil with additional materials, your costs will increase.
Other cons to building an earthbag building are:
- Labor-intensive construction technique – if you have ever filled a sandbag, you know how laborious it is. Imagine filling thousands of sandbags just to build one structure. The process is time-consuming but will get you in shape.
- Complicated building permits – some counties are more flexible when it comes to others. You may have trouble getting the building permits you need to construct your earthbag home.
- Walls are heavy and dense – Earthbag walls do not allow easy plumbing and electricity. You may want to consider a different construction method for interior walls.
- Region-specific – earthbag construction should only be practiced in warm and dry climates so the bags don’t expand and contract.
Once you have weighed the pros and cons of this building method, it is time to learn how to construct an earthbag building.
Earthbag Construction Methods
There are several different techniques when it comes to constructing an earthbag home. It is important to research and get advice from earthbag house building experts who have experience building with the medium.
You can attend an earthbag school online or in-person and learn the best building practices.
This guide offers general building advice about the basic materials and processes of building an earthbag home.
Step 1: Gather Tools and Materials
The essential tools and materials you will need for typical earthbag construction are:
- polypropylene bags
- barbed wire
- wire cutters
You will also need the right tools for constructing doors, windows, interior walls, and the roof. There will be additional tools for finishing your walls as well.
Step 2: Fill Hundreds of Earthbags
Fill your bags with desired materials to 90% capacity. Make sure to use the exact amount of fill in each bag to achieve consistency. You can do this by marking the fill level on the bucket and counting how many buckets per bag are needed.
Filling earthbags is a two-person job, one to fill the bags and one to hold them open. However, you can construct an earthbag stand that keeps the bag open while you fill it, eliminating the need for another person.
A 6×12 foot wall takes an average of 288 earthbags, so you will need to fill hundreds, if not thousands, of bags.
Step 3: Set up Foundation
There are many different ideas for making an earthbag foundation. For example, some builders lay the bags directly on the ground, while others pour concrete for the bags to sit on.
One of the top recommendations for a foundation is to dig a trench 6-12 inches deep and fill it with gravel. Then lay your bags on top of the gravel. You must tamp the bags down to get any wiggle room eliminated.
Step 4: Build Walls
Once you have laid your first course of bags on the gravel foundation, you need to run at least one strand of barbed wire atop the bags. This will ensure that your bags do not slide around.
When you lay your second course, stagger your bags like masonry work.
Step 5: Frame out Windows and Doors
Before you get too deep into building your walls, frame out where you want your doors and windows. You can always revise an earthbag house but start a well-thought-out plan before building.
Make sure to leave gaps for running plumbing and electricity into the structure.
Step 6: Plaster Walls
Plastering over the earthbags is a vital step in stabilizing the walls. It also makes the construction waterproof and fireproof.
The plaster gives the earthbag house a sleek, finished look similar to historic adobe houses.
You can leave the plaster natural or paint over it. A light colored paint helps keep the structure cool in the hot summers.
Step 7: Build Roof
Building the roof for an earthbag structure is the most challenging feature. Due to unusual building shapes, it can be difficult to adhere a roof to the form.
If you are new to building an earthbag building, use the most straightforward roof design. The simplest roof design is either a flat or pitched roof, made with plywood and sealed for moisture.
If you build a dome structure, earthbags and scaffolding create the roof.
Many sandbag houses have a living roof consisting of dirt piled on top of a sealed flat or pitched roof. You can then plant grass or flowers atop the roof, allowing even more insulation benefits.
Earthbag Construction Tips
You can utilize a few essential tips to make your earthbag build safer and more effective.
- Tamp down every bag – you will need to get a tamper tool and tamp down every bag.
- Fill gaps with custom bags – unexpected gaps will happen in your construction. Use partially filled bags to fill gaps in the wall, next to doors and windows.
- Use a slider to place bags – getting your earthbags next to each other can be difficult. You can use a metal slider to slip the bags in place to achieve the tightest fit possible.
- Use a level every time you place a bag – the success of building earthbag walls relies on the bags being completely level. The integrity of the structure will compromise if the walls start to lean.
This tutorial covers the basics of how to build an earthbag house. You will want to explore many more ideas and principles before diving into an earthbag construction.
Earthbag House Interior Ideas
Earthbag home interiors can be creative, using arches, interior pass-through windows, and portholes within the walls.
You can also build nooks, sitting areas, and couches out of earthbags integrated into the structure or you can inlay all sorts of shelving and storage into the walls. You can even build a fireplace into the interior, creating a seamless look and feel.
Many homes build their kitchens out of earthbags, from countertops to pizza ovens.
There are some things to consider before you decide to structure your interior walls from earthbags:
- Limited plumbing – you will need to consider how to add in your plumbing before you construct your home. Since the walls are solid, you cannot run pipes through them once built.
- Running electric – Although the wires are not too hard to blend into the interior, outlets can be problematic as you don’t want them to stick out.
- The wall’s density and mass – the average thickness of a sandbag wall is 15″ and may not work well in a small interior.
Once you have addressed all the technical interior wall issues, you can let your imagination run wild with creativity and design.
Frequently Asked Questions (FAQ)FAQ
How long does an earthbag home last?
An earthbag dwelling can last for centuries in dry climates, and many adobe homes still stand from hundreds of years ago in the desert. The oldest adobe house still standing in America is in New Mexico and dates back to the 1600s.
How much does earthbag house cost?
An earthbag house costs $7 to $15 per square foot. There are many variables, including doors, windows, roof, and fill expenses.
How many earthbags do I need to build a house?
You will need an average of four bags per square foot. For example, a 6×12′ wall is 72 square feet and will take 288 earthbags to construct. This is an estimate and will vary on the size of the bags.
How do you insulate an earthbag house?
The thermal mass of the earthbag house provides insulation. You can add extra insulation with straw bales placed along the walls’ exterior or insulate by packing the home’s exterior shell with dirt.
How long does it take to build an earthbag dome?
A simple round dome takes an average of 30 days for two people working 8 hours a day. This figure includes the foundation, building the walls, framing, and roofing. This figure does not include filling the bags, which can take a tremendous amount of time.
What is the R-value of an earthbag home?
The R-value of an earthbag house depends on the composition of the earthbag fill. It can range from R-26 to R-30, similar to a straw bale wall.
What do you fill earthbags with?
The goal is to use the natural dirt on your property, but you may have to amend your soil with vermiculite, crushed volcanic stone, rice hulls, or even clay if your soil is too sandy.
How do you seal earthbags?
Fold the end over and connect the folded end of the bag against the previously laid bag. This method will seal the bag. You can also stitch the end of the bag closed, but it is not necessary.
How thick are earthbag walls?
Walls built of earthbags are about 15″ thick, including the plaster. This will vary on the size of the earthbag you use.
Do earthbag homes have to be round?
An earthbag home can be any shape you want. The structure can be rectangle, square, round, ellipse, or even triangular. Always use the best building practices when shaping your earthbag house.
Are earthbag homes safe?
Earthbag homes are incredibly safe and can be safer than traditional homes. They are rodentproof, waterproof, fireproof, bulletproof, and stand up to storms and earthquakes when properly constructed.
Are earthbag homes tornado resistant?
Earthbag structures can be tornado, hurricane, and wind-resistant. Dome and round earthbag houses fare better through these disasters than rectangular builds.
Are earthbag homes cool?
Earthbag construction keeps cool during the hot summer months due to its thermal mass. Make sure to use proper fill for the best cooling effect.
Earthbag Homes Conclusion
Building an earthbag home is exciting, creative, and is an excellent alternative to using standard building methods.
You have the potential to build a beautiful, sleek home with curved walls and unusual shapes. You are also helping the environment by using dirt as your primary building material.
Building an earthbag house is similar to masonry construction techniques. Each earthbag layer overlaps and is held in place by barbed wire, creating a strong bond between layers.
Although the construction of an earthbag building is simple, it takes a lot of experience to perfect the system. Therefore, it is important to gather advice from experienced earthbag builders and research the topic.
Building an earthbag home is fun and rewarding, yet challenging and laborious. If you do decide to commit to building an earthbag house, make sure to get advice from a professional or hire an experienced builder to do the work.