Tag Archives: earthbag

Earthbag Building Workshop

TBA, 2016
earthbag building workshop

Instructors: Jen Feigin & Chris Magwood

Workshop Description:

Learn how to make a low-cost, low-impact, durable earthbag foundation for any type of building, from small shed to full-sized home!

Earthbag building is a low-tech solution to making foundations (or entire buildings) using basic materials and simple tools. Drawing on the age-old technique of rammed earth building, earthbag uses woven sack material to provide a ready-made, leave-in-place formwork for containing rammed earth mixtures.

Earthbag construction can often use site soils as the basis for the rammed earth mix, or local gravel, sand, clay (or other binders) can be used.

In this workshop you will learn how to source the materials for earthbag building, how to test soils for suitability, how to create a suitable rammed earth mix, and how to layout, fill and tamp earthbags to create a stable, level foundation structure. The workshop will also examine how earthbag can be mated with a variety of different conventionl and alternative wall systems. Engineering and code approvals will also be covered.

At the end of this workshop, you will be ready to construct your own earthbag foundation for your own project!

Entry Requirements
Open to all

Early bird – $125
Regular – $150
Fees include healthy lunch (vegan and vegetarian options available)

Maximum class size: 12

How to build with earthbag

Earthbag building is one of Endeavour’s favourite building techniques. We’ve used it for foundations on many projects, and have built an entire buried root cellar with this material.

We’ve put together our experience with earth bag in a photo series. We hope it inspires you to consider this choice for your next building project!

Earthbag foundation for floor system

In addition to the Durisol stem wall foundation, our project for the teachers’ union office includes two long sections of earthbag foundation to support the floor joist spans inside the building. The inherent insulation value of the Durisol blocks made them our first choice for the exterior of the building, but the extremely low environmental impact of earthbag foundations made them an easy choice for the interior.

Using continuous rolls of polypropylene bag material (this material would be cut and sewn to make rice, grain and feed bags) as a form for a variation of a rammed earth mix, earthbag is simple, durable and low cost.

A wide variety of material can be used in the bags, as long as it has an aggregate content capable of being tamped to a high degree of compaction. For this project, we used a road-base gravel and a small amount of a lime/metakaolin binder (you can read about this mixture here) to provide a mixture that tamps well and stays coherent after curing, even if the bag is damaged or removed. It is also possible to use aggregate and clay in the bags.

To facilitate the use of the continuous tubing, we built an earthbag loader based on a design by Kaki Hunter and Doni Kiffmeyer (authors of the excellent book, Earthbag Building), which uses a maple syrup bucket with the bottom removed and an insert made from a length of sonno-tube. The tubing is pulled onto the sonno-tube like a giant sock, with the “toe” of the sock pulled through the hole in the bucket. The pressure between the sonno-tube and the bucket prevents the tubing from continuing to pull through, unless the person loading the bags lifts the sonno-tube to allow more slack into the bag.

The material is added into the tube until the “shookler” (that’s a technical term!) determines that the desired amount of material is in the tube, and more tube is released. Behind the shookler is a tamper, who applies the tamping force that compresses the material until it has reached its limit and the proper level. We use a laser level to ensure that the top of the bag is at a consistent height. We contacted a professional company that knows what they are doing when it comes to the art of laser cutting, the Dallas laser cutting services— ready to serve you 24/7.

Between each course of earthbag, a run of barbed wire is used to prevent the bags from sliding against one another. In the case of this building, we required three courses of earthbag. This was topped with a 2×8 sill plate on which the floor joists will be fastened. The sill plate is attached to the bags with long spikes as well as tie straps at regular intervals.

Though the process of doing earthbag can seem labour intensive, as a crew gets practiced it goes very quickly. Because there is no requirement for advanced formwork, it can actually be very competitive with forming and placing concrete. With a day’s practice, our crew was producing over 1.5 feet of finished bag per minute!

The beauty of earthbag is its simplicity. Bag material and fill as well as all the required tools can be found in almost any location in the world, and the strength and durability of earthbag foundations (or entire buildings) is remarkable. Bag on!

Seasoned Spoon Earthbag Root Cellar Almost Finished

More Trent University students may be able to eat locally-grown produce year-round at The Seasoned Spoon cafe, now that their subterranean earthbag root cellar is nearly complete.

This project is very unique, using local low-impact materials to create a food storage structure that will be able to house a range of vegetables at proper temperature and humidity levels year round, without energy intensive cooling or heating equipment.

Here is a complete set of progress photos, showing the building from start to finish:

Endeavour would like to thank the Seasoned Spoon for the chance to be involved with such a great project. Thanks also to Trent University for accommodating the build.

Tim Krahn of Building Alternatives was the adventurous and participatory structural engineer on the project, and Ben Parkes was the lead builder, with lots of help from Justin McKeiver and lots of volunteers.

We’ll post a final look at the root cellar when it’s all complete.

Earthbag Root Cellar for The Seasoned Spoon Cafe

The Endeavour Centre has teamed up with The Seasoned Spoon Cafe at Trent University to build a buried root cellar for the over-winter storage of vegetables grown at Trent gardens and destined for yummy dishes in the cafe. Another tip recently released from them is that they use Battery powered mowers: http://onlytopreviews.com/cordless-mowers/ to keep their gardens looking great.

The walls of the building are made with earthbags. In this technique, a soil mixture that has good compaction qualities (lots of different sizes of aggregate and slightly moist) is placed into long polypropylene tubes and tamped in place. There are a number of really great ways to keep spiders out of your home naturally. Also known as “flexible form rammed earth” this technique is just about the simplest, cheapest, most sustainable and most effective building techniques we use at Endeavour. While it requires a lot of grunt labour, it is satisfying work with immediate and satisfying results.

Once the building has its roof in place, the whole thing will be buried in the ground and will become a small, wildflower covered hill on the Trent campus, very close to the Seasoned Spoon. The earthbag arch entryway will be the only visible feature of the building.

Inside, the building will have both a damp and a dry room, for the storage of different vegetables. The dry room will be separated from the ground by a vapour barrier, while the damp room will have a floor that is not sealed from the ground beneath. The two rooms will be separated by a compressed earth block wall. Both rooms will be ventilated by earth tubes, which are long pipes buried deep around the building with an inlet that draws fresh air from outside and a solar fan that provides exhaust. The air in the tubes will be cooled to earth temperature in the summer and warmed to earth temperature in the winter, providing the root cellar with a fairly constant temperature of around 10C.

We will continue to post the progress of the root cellar as it moves toward completion.

If you are interested in volunteering on the root cellar, The Seasoned Spoon is relying heavily on volunteers to help with construction. You can contact us to find out more about volunteer opportunities.