This is the first of two posts about the sustainable features and systems here at Ironwood Farm Project. Chris has happily obliged to answer my questions in an effort to inspire and inform others looking for options. But please remember this is not as comprehensive as it could be! There is a lot to sustainable housing (including completely different methods) that is impossible to explain in a single post.

Also, when it comes to sustainable housing you are obviously going to have a lot more versatility when it comes to building a home from the ground up (which is what was done here) vs retrofitting a pre-built home (which is likely what most of us are or will be working with). But at least this post will throw out some of the ideas implemented here and hopefully get you started in your search for more information.

Me: Chris, you started from the ground up, correct? Let’s start with the basics: What materials did you use for the structure and where did you source them?

Chris: We started with an empty field. We sourced everything as close to us as possible. We brought in dirt to make a mound for the house to bring it above flood elevation and crushed concrete for the driveways from a nearby demolition company.

The foundation was made out of an insulated concrete form called RASTRA, which is a material that has been used in Europe for a long time. A local company manufactures the blocks using waste foam from Intel Corporation.

The house is straw bale with a timber frame and covered with an adobe plaster. The plaster was sourced from forty feet from the house; the clay was on the surface and we dug digger to reach the sand. The timber framing was made from 2x4s and OSB (chipboard). Those were new products brought in from a distance but we chose them specifically because they were very light in mass, so the shipping was “greener”.

The straw bale was used because it’s easily renewable and for its insulation properties. It’s also durable and fire-resistant (think of burning a crumpled piece of paper vs burning a thick phone book). We sourced from Southern Colorado, which was the closest source of construction bales. Construction bales, made from barley (in this case, a byproduct from Coors Brewing Company), are very uniform and dense. Barley is also sturdy enough to not crush when being baled; this protects the air space within the straw for added insulation.

The ceiling is insulated with about 16 inches of blown-in cellulose and the roof is galvanized metal. We chose a metal roof because of its durability, longevity and reuse-ability.

We used as many salvaged items as possible: all the doors (exterior and interior), many of the windows, tile flooring, wood from pallets for ceiling tiles, all the trim lumber, and cabinets. We also used adobe flooring and adobe bricks for interior walls.

Me: What kind of passive design elements were implemented to save energy?

Chris: We built large south-facing windows with a slight pitch to the east to protect from intense western sun in our particular climate. Interior adobe (floors and walls) act as a thermal mass to store heat or “coolth”. We emphasized an open floor design with large doorways and pass-throughs in the walls (essentially holes that assist in circulating warmed or cool air from one room to the next). We put in hydronic tubing under the floor but haven’t needed to hook them up. When we irrigate we have the ability to run the irrigation water through the tubing before running it to the gardens, which will cool the house. We also added earth tubes, which can conduct thermally tempered air into the house.

Me: Let’s talk about the work: How much of the labor did you do yourself and who helped? Did you find yourself needing to hire contractors or barter skills?

Chris: All of the above. We had our hands in everything from the design to the electrical. We hired a contractor to oversee the framing and roofing. And we had very large numbers of volunteers – family, friends, coworkers, neighbors and random strangers.

Me: How long did it take you from the time you broke ground until the time you moved in?

Chris: It took about three and a half years, but it wasn’t completely finished at that point. We passed our occupancy permit so everything functioned but some of the rooms were built after we moved in. Because much of our materials were salvaged, a lot of our planning happened as we went, which slowed us down and complicated things.

Me: Energy is obviously a key factor in sustainable housing. Can you talk a bit about the energy needs of the house and how you meet those needs?

Chris: We have a solar electric system with 920 watt PV panels and eight L-16 batteries. The inverter is 3000w, sized partially for running large power tools needed in construction and on the farm. The fridge and freezers are DC, which is more efficient and you don’t have the energy losses with converting from DC to AC power. We setup switches for turning off phantom loads, use CFL bulbs,  and purchased very energy-efficient appliances and electronics (such as box freezers, instead of upright freezers). We also have a wood-burning stove for backup heat and cooking, which is rarely needed. Our water heater and stove are propane.

Me: And what about water? Where does your water come from and what water-saving features does your house implement?

Chris: The water comes from a well about 200 feet below the house and is pumped from a submersible pump that is directly driven from solar panels (separate from the house system). There are no batteries, only a pressurized tank, which means a limited volume of water can be utilize overnight. The house is designed for rainwater collection with a single-sloped roof and a single central downspout and catchment tank. Greywater from the house can be plumbed into the yard. There is only one bathroom with the composting toilet. And all faucets and the showerhead are, of course, low-flow.

Me: Looking back, is there anything you would change?

Chris: There are probably a multiple of small design features I would and still can change, such as a porch on the west side of the house to assist in shading from the western sun. Also, if we had had the confidence that the house would have performed as well as it has, we could have saved money and resources with some of the features we installed and don’t use (such as the hydronic tubing and earth tubes). And then just small mistakes such as inconvenient placement of light switches.

Me: What are your future plans for the house? Do you plan to add anything?

Chris: Yes, we plan to hook up the greywater and rainwater catchment, build a porch and greenhouse off the south side (as initially designed) and finish the exterior plaster. And then build shelving, organize it all and finally have a place for everything and everything in its place!

Me: What skills or resources would you recommend a person have before undertaking their own sustainable housing project?

Chris: If you do not possess some skills of basic construction then you need to be a very hands-on person and a quick study. Apprenticing and working as a volunteer (for Habitat for Humanity perhaps) is a huge asset. Even if you know the basics, putting it all together is a totally different thing, especially if it’s alternative.

Me: Anything else you would say to someone undergoing the same project? Or resources you can recommend?

Chris: The straw bale building books helped me, especially the less commercial, more “homegrown” books, such as Build It With Bales. Working in phases and giving yourself time to work with salvage and earthen materials can also be a good way to go. Also, the KISS rule: Keep It Simple, Stupid.

If you’re interested in more of what Chris is doing or has done, visit his blog Ironwood Farm Project to contact him or volunteer.