Regenerative Construction: an Oxymoron?Mar 27, 2019
By Rebecca Tasker from Simple Construct
At its most basic, construction is a destructive and consumptive process. It requires getting a lot of stuff from somewhere, processing it, and putting it together in a different way. It usually involves mining, logging, milling, refining, smelting, shaping, packaging, and shipping the materials. Then it often involves cutting, nailing, mixing, spraying, coating, sanding, and the use of all manner of power tools. It is inherently destructive (no raw materials = no stuff) and consumptive (no stuff = no building).
Destruction and consumption are fundamentally at odds with regeneration. Regeneration is about renewal, restoration, improvement. In a balanced system, regeneration is the other side of the scales from destruction and consumption.
Because of this, it is has been hard to imagine truly regenerative construction. It is a high bar. The green building movement first focused on doing less harm and using less energy, asking “How do we cut down fewer trees and make our buildings burn less fossil fuel?” In recent years, we dug deeper to look at using materials that do less harm and need less energy to be created (embodied energy) by asking “How do we make the materials that go into the building less toxic and less consumptive in their manufacture?”
It seemed like doing the least amount of harm to our ecosystems and environment was the highest goal, the ultimate finish line. It was a good place to start but now we need to move beyond that to try to build in a way that not only does less harm but actually does good, is a positive force, helping to repair some of the damage already done. How can construction be an active force of regeneration, restoring and improving the environment?
What if the materials that we build with could act as carbon sinks, collecting and storing carbon out of harms way? What if these materials pulled harmful CO2 out of the air and locked it up safely in the very structure that makes them ideal building materials? Straw is a wonderful example of this phenomenon.
According to preliminary research done by the California Straw Building Association, a bale of straw locks up approximately 60 times as much carbon as was emitted making that bale. That carbon is then safely stored as long as that bale is used in a way that it will not break down — in a wall, for example. It’s a net positive way to sequester carbon that has the convenient side-effect of making beautiful, comfortable, energy-efficient buildings.
So we can now add carbon sequestration to the already long list of the benefits of building with bales:
- Great insulation: Straw bale walls provide at least R-30 insulation, which can greatly reduce energy used for heating and cooling. A typical 2×6 stud wall with maximum fiberglass insulation is rated R-19.
- Good for people and the environment: Straw is an agricultural waste product leftover from the production of grain. Straw bale building is not only an example of recycling, is a great example of up-cycling. It is a natural, zero VOC material that will not add toxins to the home.
- Good fire resistance: Straw bale walls have a very good fire rating: 1 hour for clay plastered walls, 2 hours for cement-lime plastered walls. A typical stick-built, drywalled wall has a 30 minute rating.
- Less materials: A plastered bale wall replaces the insulation, the drywall and the paint usually used in a conventional wall, and can reduce the wood needed for framing.
- Better sound quality: Straw bale walls provide excellent sound insulation and have a positive effect on interior acoustics
- Better air quality: Straw is a natural, non-toxic building material, lending itself to zero VOC finishes (such as clay plaster) which can lead to a healthier indoor environment.
- User-friendly: Building with bales can create opportunities to involve your friends and community through bale raisings and work parties.
- Beautiful: Straw bale walls are aesthetically versatile. They can be straight and flat or can be shaped to have sinuous, organic lines and accommodate built-in furniture or niches. Straw bale homes can be almost any style: from straight and Modern to handmade and cottage-like; from organic and ‘Hobbitty’ to clean and Contemporary.
And the carbon sequestered in the bale is just one part. In addition to sequestering carbon above ground in the form of the visible plant, carbon is also ferried down into the soil by the roots of the plant. Research is just starting to scratch the surface of the potential for soil to sequester carbon but the potential is immense.
The next step in this quest to build regeneratively is to question what role agriculture can play in helping (or harming) the process of sequestering carbon in the soil. Currently, most of the bales we are able to obtain come from big agribusiness farms using unsustainable farming practices. They are mono-cropping an annual plant that is highly fertilized, requires pesticides, and is completely harvest ever year, disturbing and depleting the soil.
Although we are doing good things with those bales, we should recognize that they are a by-product of a destructive and non-regenerative system that needs to change. In a regenerative system, there is no such thing as waste: it is a closed loop where waste becomes fuel and food. The wheat stalks that make up our straw bales should not be leaving the field, they should be going back into the soil to decompose and feed the next generation of plants. Or, to take it even further, the plants should not have to be harvest completely each year. Grain and some of the stem material could be harvested from a perennial plant, leaving its root system in place to feed carbon into the soil, prevent erosion, continue to participate in the complex soil food web.
Transitioning to bales made with stalks of perennial plants grown in a polyculture could increase the amount of carbon stored in the soil. That would not only help to remove harmful CO2 from the air, it could improve the quality of the soil and water; reduce nutrient loss and erosion, and increases water conservation and crop productivity.
Currently, it would be difficult — if not impossible– to find enough truly sustainably-farmed bales to build many houses, but it is an admirable goal.
Now that we have started to understand the potential for strawbale and other biomass building materials to take carbon dioxide out of the atmosphere and safely lock it up, the term ‘regenerative’ seems like less of a stretch.
It’s been a slow progression from making buildings use less energy (operational energy), to building with materials that are made with less energy (embodied energy/embodied carbon), to finally starting to look at building with materials that absorb more carbon than they created (carbon sequestration). From this new viewpoint, a mindfully-designed, well-placed, carefully-sourced, skillfully-built, bio-based building can truly earn the label “regenerative.”
“The New Carbon Architecture: Building to Cool the Planet,” by Bruce King and friends
“Beyond Sustainability? — We are living in the Century of Regeneration” by Daniel Christian Wahl