Tag Archives: natural building

Jumbo bales and hempcrete – together!

Fifth Wind Farms wanted to create a building that could reach the energy efficiency requirements of the Passive House standard without resorting to the use of foam, mineral wool or other materials with a high carbon footprint. While straw bale buildings can have excellent energy performance, typical straw bale construction does not meet the Passive House standard without the addition of an extra layer of insulation (see our “Straw-Cell” project for a different take on this idea).

Jumbo straw bale duplex home

First jumbo bale in place (on a bed of Poraver insulation)

The building owner proposed the use of “jumbo bales,” which are produced from the same local straw and by the same low-carbon machinery, but are of dimensions that greatly increase their thermal performance. While typical straw bales are 14″ x 18″ x 32″, the jumbo bales used for this project measure 32″ x 32″ x 60″! At a nominal R-value of 2.0 per inch, that would give a jumbo bale wall a rating in the range of R-60, more than enough to help the building meet any energy efficiency rating.

However, the jumbo bales provide some issues when it comes to window and door openings… with a wall that thick, window sills and returns are extremely deep, creating not just aesthetic concerns but also concerns about air flow in the deeply recessed bays and the likelihood of condensation forming on the windows in cold weather.

Our solution was to form the window sections at a wall depth of 16″ using double stud framing and hempcrete as the infill insulation. This would keep us on track as far as low carbon footprint is concerned, and the hempcrete would be used to create the tapered window returns to meet the full depth of the bale walls. As a bonus, the hempcrete would completely fill any voids at the ends of the jumbo bales.

One issue with using jumbo bales: they weigh over 500 pounds each! We used a boom truck to install them in the building. With the bales in place and the top plate secured over the bales, we then mixed our hempcrete (you can find our recipe here) and tamped it into the framing and around the jumbo bales. The two materials are very complimentary, with the easily-formed hempcrete able to compensate for the uneven ends of the jumbo bales and creating smooth window returns.


The building is currently being prepared for plastering… more posts to follow soon!

Sustainable Building Essentials from Endeavour and New Society Publishers

The Endeavour Centre is partnering with New Society Publishers to bring natural building enthusiasts a new series of books intended to cover the full spectrum of materials, systems and approaches to natural building.

Sustainable Building Essentials books

Called the Sustainable Building Essentials series, the books cover the full range of natural and green building techniques with a focus on sustainable materials and methods and code compliance. Firmly rooted in sound building science and drawing on decades of experience, these large-format, highly-illustrated manuals deliver comprehensive, practical guidance from leading experts using a well-organized step-by-step approach. Whether your interest is foundations, walls, insulation, mechanical systems or final finishes, these unique books present the essential information on each topic.

The first three titles in the series are now available for pre-order from the publisher, with a 20% discount:

Essential Hempcrete Construction

Essential Building Science

Essential Prefab Strawbale Construction

Upcoming titles in the series include:

  • Essential Straw/Clay Construction
  • Essential Green Home Design
  • Essential Rainwater Harvesting
  • Essential Natural Plasters
  • Essential Cordwood Construction
  • Essential Composting Toilet Systems
  • Essential Green Roofs
  • and many more…

We hope that this series helps continue Endeavour’s mission to bring affordable, accessible and accurate sustainable building information to a wide audience!

Light clay straw insulation

On April 10, a workshop at Endeavour led participants through the theory and practice of making wall insulation from light clay straw (also known as straw/clay, slipstraw, or EcoNestTM).

This is an insulating technique we’ve used numerous times on building projects at Endeavour, and we appreciate the extremely low carbon footprint, simplicity, lack of toxicity and simple installation process of this insulation.

Here is an introductory slide show about light straw clay insulation:

Clay slip versus dry mixing
During our workshop, we used the typical mixing approach for light clay straw insulation: mixing our clay into water until we had a thick, “melted milkshake” consistency. This slip is then poured onto the straw and mixed in until the slip evenly coats all of the straw, so that a handful of straw can be squeezed into a shape that reasonably retains its shape. Whether mixed by hand, in a mortar mixer or in a purpose made straw/clay tumbler, this is how we and other straw/clay builders typically prepare the insulation.


For this workshop, we also tried a mixing technique more similar to that we use for hempcrete. When mixing hempcrete, the hemp hurd and the binder are added together when dry, mixed until the powdery binder coats all the hemp, and then lightly misted with water to make the binder sticky. So we tried sprinkling dry powdered clay over the straw, stirring, and then adding water. This didn’t work so well, as the clay powdered sifted down through the straw and ended up at the bottom.

Dry mixing, version 2
For our next batch, we reversed the process and gave the straw a light misting of water and then sprinkled in the clay powder and stirred. This seemed to work very well, as we ended up with a clay coating on the straw that was much stickier than slip mix and allowed the clay/straw to be packed into the forms easily. This process used 25-50% less clay, and more importantly 25-50% less water, which should reduce drying time in the wall dramatically. Having placed both slip-mix and dry-mix side-by-side in the same wall system, there was no appreciable difference in quality in the finished appearance of the insulation, but the dry-mix showed about 25% moisture content on our moisture meter, and the slip mix was up at 36%. Given that slow drying time is the main hang-up for straw/clay insulation, we will use this technique in the future to reduce the wait for the insulation to dry!


Hempcrete developments

On April 9, a workshop at Endeavour brought participants together to explore hempcrete insulation materials.

The workshop looked at well-used options for these materials, but also explored some interesting new approaches.

Endeavour has continued to develop the use of homemade hydraulic lime binders as a means to eliminate carbon-heavy cement from our building materials and to create locally-sourced binders for cement replacement. At this point, our homemade hydraulic lime binder is well-tested and we feel it works as well as any of the imported (European) hempcrete binders, at a fraction of the cost and with locally-sourced ingredients.

Hempcrete mix
Our hempcrete binder is composed of 50% hydrated lime (most easily accessible to us is Graymont’s Ivory Finish Lime) and 50% Metapor metakaolin from Poraver (created as a by-product of the company’s expanded glass bead production).

We mix our hempcrete at a ratio of 1 part chopped hemp hurd by weight, with 1.5 parts of the binder by weight. After translating these weights to volume measurements, it was 4 buckets or hemp hurd going into the mixer with 1 bucket of binder (1/2 lime, 1/2 metakaolin).


hempcrete insulation

Weight ratios are converted to bucket measurements: 1/2 bucket of lime, 1/2 bucket of metakaolin, 4 buckets of hemp hurd


The hemp hurd goes into the mortar mixer first and then we sprinkle in the binder and allow it dry mix until the hurd is well coated with binder powder.

hempcrete insulation

A horizontal shaft mortar mixer is used to dry-mix the lime binder and the hemp before water is misted into the mix

Water is then misted (not sprayed) into the mixer until the mix is just moist enough that if we pack it like a snowball in our gloved hands it keeps its shape, but is still fairly fragile (ie, can be broken with a bit of a squeeze). It is important to not over-wet the hempcrete, as this will greatly extend the drying time once the hempcrete has been packed into a wall. If too much water is added, the mix can’t be recovered by adding more dry ingredients as the hemp hurd will quickly absorb excess water and there won’t be any free water for the new dry ingredients. So, add water carefully and gradually!

hempcrete insulation

When packed like a snowball, the hempcrete should just hang together

Hempcrete is placed into formwork on a frame wall, using light hand-pressure to compact the mix just enough to ensure that the binder will stick all the individual pieces of hemp together.

hempcrete construction

Hempcrete is placed into forms and lightly pressed into place. The forms are leap-frogged up the wall.

Our workshop crew was able to mix and place enough hempcrete to fill a 4-1/4 inch deep wall cavity that was 4-feet wide and 13-feet high in just under 3 hours! That’s over 6 cubic feet of material per hour!

Hempcrete recycling
We have long touted the no-waste benefits of hempcrete. We’ve speculated that even when the insulation is being removed from a building during renovations or demolition, that the hempcrete can be broken up and recycled into a new mix with new binder added. We put that theory to the test at the workshop, as we demolished one of our small sample walls and added the broken up hempcrete into our new mixes at a ratio of 3 parts new hemp to 1 part recycled hempcrete. The resulting mixes were impossible to distinguish from the all-new mixes, and confirmed that hempcrete can easily be re-used!

hempcrete insulation

Hempcrete that had already been mixed into a wall was broken up and added into a new mix… Fully recyclable!

Hempcrete book forthcoming
If you are interested in hempcrete insulation, Endeavour’s Chris Magwood has just finished a book called Essential Hempcrete Construction that will be available in June, 2016. It contains recipes, sourcing, costing, design and installation instructions and will be very valuable to anybody considering a hempcrete project.

hempcrete insulation

New book includes everything you need to know about building with hempcrete

Hemp-clay shows lots of promise!
Hempcrete insulation is almost always done using a lime-based binder. But at the Natural Building Colloquium in Kingston, New Mexico last October, we were doing a hempcrete demonstration right next to a straw/clay demonstration, and we took the opportunity to mix up a block of hemp hurds with a clay binder.

hemp clay construction

A sample block of hemp-clay showed the potential for this material combination

The success of that demo block led us to try this combination on a slightly larger scale, and we machine mixed the clay and the hemp to fill one tall wall cavity with this hybrid material. Using the same mixing methodology as typical hempcrete, we added the hemp hurd and dry bagged clay to the mixer and allowed it to dry mix, before misting with water. Interestingly, we were able to use half the amount of clay binder compared to lime binder (1/2 bucket of clay to 4 buckets of hemp hurd) and the resulting mix was stickier and easy to form and pack than with the lime, and with the addition of noticeably less water.

hemp clay construction

The hemp-clay mix has great binding power, and keeps its shape with very little pressure required

The key difference between the two binders is in their manner of setting. Hydraulic lime binders cure chemically, and consume water to change the chemical structure of the mix as it solidifies. Clay binders simply dry out and get hard. So the lime-based versions should be drier and harder sooner. However, the smaller quantity of water required in the clay-hemp mix may mean that drying times end up being similar… we’ll report back when we know.

hemp clay construction

A close-up of the hemp-clay mix formed into the wall. It keeps its shape within seconds of being placed into the forms

Clay binder with hempcrete offers some advantages over lime-based options, including a significantly lower carbon footprint and none of the caustic nature of lime that can cause skin burns when handling. The clay-based binder creates a mix that is much stickier during installation, which means less packing/tamping to get the material to cohere in the forms. Less water means that it was almost impossible to over-compact the mixture. We will definitely be exploring this option in a serious way!

hempcrete insulation

Having placed 18.5 cubic feet of hempcrete in a few hours, the crew stands in front of their work. The lighter coloured hempcrete is our homemade hydraulic binder, the darker mix is Batichanvre, a binder imported from France.


Ecological Building: From Fringe to Almost-Mainstream, 1996-2016

Maybe the Weirdoes Weren’t So Weird After All

2016 marks the 20th year since the idea of building houses with straw bales completely transformed my life. Back in 1996, I wanted to build a home for my family that would achieve two seemingly simple goals:

  1. The home would make our lives financially sustainable by being affordable to build and having very low operating costs
  2. We’d have a smaller impact on the environment than conventional practices

While these were not particularly radical or even new goals, they certainly weren’t ones that we shared with many other people at the time. Our decision to go ahead and build the first code-permitted straw bale home in Ontario was met with many more quizzical looks or outright expressions of derision than interest or congratulations. Almost all of our reasons for building a low-cost, energy-efficient and environmentally friendly home where met with the question, “Why?”

cooper straw installation

Straw bales almost tripled the code requirements for wall insulation in 1996.

You’re Using R-What?
Then: The notion of insulating a home was well accepted by that time (and even mandated by the building code), but the notion of using anything more than the low code minimum was largely seen as excessive. No insulation was required for basements or under slabs, and air tightness was only being discussed in whispers. The R-2000 program had been around for a while, but even many of its proponents thought the idea of a straw bale wall’s R-40 (or so was the number used at the time) and our plans for R-48 in the roof was kind of overkill. The most receptive audience for the kind of energy efficiency promised by straw bale building was among individual homeowners eager, like us, to greatly reduce or even eliminate heating bills from our monthly overhead, effectively “buying” us a degree of freedom from financial burden.

Now: This is the one area in which conventional building has started to wholeheartedly adopt the strategies of the early green builders. The building code is on a planned pathway to ever-higher levels of insulation and energy efficiency, including targets for improved air tightness. There are numerous voluntary standards to encourage homeowners and builders to exceed code minimum efficiency (such as LEED for Homes and Energy Star), and software programs for modeling energy efficiency. The Passive House standard, nearly unthinkable back in 1996, is gaining traction and showing what’s possible when energy efficiency is taken really seriously. It won’t be long before straw bale walls at R-30 barely meet code requirements, and must already be exceeded to meet the higher standards. It has never been so easy to build a truly energy efficient home.

cooper frame

Recycling old barn timbers was just one strategy to lower the environmental impact.

Environmental Impact from Buildings?
Then: Even less understandable at the time was the urge to build with less of an “ecological footprint.” Even the term itself, which seems to have surfaced in 1992 (coined by Canadian ecologist and University of British Columbia professor William Rees), was unusual at the time, and the notion that choices regarding building materials could have a huge impact on the planet was just starting to be raised as an issue. The fledgling US Green Building Council, formed in 1993, was at the forefront of bringing this issue to light in North America… but nobody was really paying attention. And the idea that these environmental impacts could include climate change due to the high carbon output in the harvesting and production of building materials was nowhere on the public awareness radar.

Now: While there is still a long way to go to remedy the vast impacts that our building materials have on the environment, the problem is at least recognized and seems likely to start to be addressed seriously in the near future. An ever-growing body of data (ICE, EcoInvent, Green Footstep) can help to quantify environmental impacts, embodied energy and, of recent government and citizen concern, carbon footprint. I spent a year of my life writing a book called Making Better Buildings that presents data for a wide range of conventional and green building approaches. It is much easier now than ever before to have an understanding of the impact a building will have on the environment and make informed choices to minimize these impacts. Not many are making these choices, but the groundwork exists and government encouragement to make them seems likely. Advocates for materials like straw bale had a sound argument to make in 1996, and it finally seems to be catching the ear of the wider culture just now.

cooper solar gear

Home made solar thermal collectors and a cobbled PV system allowed for energy independence.

Renewable Energy?
Then: Our decision to go “off-grid” with our straw bale home wasn’t part of our original plan. But the high cost of hooking up to the grid mixed with a rapidly dwindling budget led us to live our first year or two in the home with no electricity other than a car battery hooked to the water pump. Surprised by the lack of discomfort (ample hot water came from solar collectors and a woodstove jacket), we were able to approach the idea of designing an off-grid electrical system as a way to provide “luxuries” like reading lights, a stereo and laptop computer use. Starting small, the system grew over time to include photovoltaic panels, wind and micro hydro. It was far from the slick systems that are readily available (and less expensive) today, but it met our needs and awakened my interest in examining conventional use of household energy and how high levels of personal comfort could come from vastly reduced consumption. From refrigerators that use cold air in the winter time to augment electric compressors to forays into early forms of LED lighting, the potential for minimizing needs without sacrificing amenities became a passion.

Now: The incredible drop in cost for photovoltaic panels has put renewables on a nearly even footing with fossil fuel energy… Incredible, considering the high levels of subsidies given to fossil fuels versus renewables. Here in Ontario, the MicroFIT program makes it financially prudent to put green energy onto the utility grid, and similar programs exist around North America. Energy storage is a top priority among researchers, with new battery technologies and systems beginning to make it to market. The distinction between being on- and off-grid could get blurry in the next decade as shared distribution of renewable energy on the grid combines with household storage capacity to re-shape household power solutions. This is one area where there are both improvements in the technology and more widespread adoption than twenty years ago. Codes, however, do not address these issues at all.

C&J's dining room

Non-toxic finishes were difficult to find, and often ended up being home made.

Sick Buildings and Healthy Materials?
Then: The World Health Organization coined the term “sick building syndrome” in 1984, as part of a study that found that over 30% of new or newly renovated buildings were the subject of health complaints by the occupants. The International Institute of Building Biologie and Ecology was formed in 1987. Not many people were listening. But this did not stop academic and lay researchers from questioning the ever-growing number of untested chemicals being combined in our building materials and wondering about the health impacts on building occupants. Those few who were concerned with this issue did not have a wide selection of commercially available products identified as being non-toxic to choose from. Homemade finishes were one important means of having control over what went into a building.

Now: Though an increasing volume and quality of research is showing the negative health effects of toxins in our buildings, this is an area has made very little headway into the mainstream. This despite the fact that we all have a vested interest in living and working in non-toxic buildings.

Small companies began to surface in the early 2000s dedicated to producing building materials free from proven or potentially toxic compounds. While few of these have mainstream distribution channels, it is entirely possible to build an entire house that has no or very little questionable chemical content. Programs like Declare and Cradle-to-Cradle ask manufacturers to fully disclose the ingredients for their building products, and the Living Building Challenge and other programs have chemical red lists to help homeowners and builders avoid potential toxins. There is no recognition of material toxicity in codes.

Low Cost Options
Then: A more regulated residential building sector was just a gleam in regulator’s eyes in 1996. The pathways for owner-builders to pursue innovative projects were less cluttered with requirements, and builders could operate much more informally, outside the scope of prescriptions, taxation and regulation. This meant that several layers of cost did not necessarily have to be borne by a project budget then. Building wasn’t exactly cheap twenty years ago, but the possibilities for building less expensively were there to be pursued.

Now: More regulations that are more strictly enforced have definitely raised building costs over the last two decades. And building material costs have risen at a rate that has exceeded general inflation. Many decades of treating real estate as short-term investment have raised land and building costs, making the cost of projects higher. Development charges, service fees, an increasing reliance on engineering approval and a more formalized scenario for builders have all put upward pressure on costs. It is more difficult than ever to build affordably, so even though the costs of building greener are well within the parameters of conventional costs, those conventional costs are increasingly out of the ability of a typical family to afford. There is no way my family and I could have acted on our 1996 dream if we were in the same position now in 2016. And that is saddening.

Everyone is Coming Down This Path
The forefront of ecological building is still a long way away from mainstream practice. But it’s not nearly as far away as it was twenty years ago; not a result of the leading edge practitioners being less adventurous or pushing less at the boundaries… rather, it’s the mainstream starting to pay attention. It may be a bit like watching a brontosaurus slowly turn its head to acknowledge an annoying bite on its tail, but it is starting to turning around.

Energy efficiency got the construction sector’s attention first. Material impacts on the environment (especially carbon) are increasingly gaining notice, and action on this front is likely in the near future. It won’t be long before occupant health likewise finds active proponents in government and industry, and the presence of toxins in the built environment begins to be treated as seriously as it should.

As I watch the behemoth slowly react, it seems worthwhile to acknowledge that, as with so much social change, the changes start on the fringe with creative thinkers and early adopters acting well outside the mainstream. It turns out that the weirdoes in 1996 were onto something, and that something is looking more and more like it makes “common” sense!

Green & Healthy Home Renovation series

Greening Your Kitchen & Bathroom
– Tuesday, November 1

Improving Your Home’s Energy Efficiency
– Tuesday, November 8

Choosing Healthy Paints, Finishes & Flooring
– Tuesday, November 15

All presentations 6 pm to 9 pm
Endeavour Centre, Peterborough

Instructor: Chris Magwood

Are you looking to renovate your home in a greener, healthier way? There is so much conflicting information out there it can be hard to know what to do.

Don’t get your information from a salesman!
This series of evening presentations gives you a chance to learn about a wide range of options from an unbiased source – long-time sustainable builder Chris Magwood. As the author of the book Making Better Buildings, Chris has made a name for himself for giving good, well-researched and honest advice to home owners about how to make the right green choices to meet their own unique goals.


See and experience a wide range of options
Not only will you learn about how to assess and choose green building options, the Endeavour Centre classroom is a living laboratory of green building and you will be able to see and experience samples of materials, systems and products.

Affordable and practical green solutions
Most people think that renovating in a green and healthy way will cost them a lot more money, but that’s not necessarily the case. The Green Renovation Series offers practical advice and a real focus on affordability to help you meet your goals on your budget.

Get answers to your questions
Each presentation will include a generous amount of question-and-answer time, allowing you to get specific advice on your own projects. A hand-out will be included to help you source all the materials and systems discussed during the workshop.

Put 20 years of green building knowledge to work for you
Finding out how to make choices that are healthy for you and your family and for the planet is a lot less difficult than you might think. Each of these 3-hour presentations is lively, engaging and informative. Come to any one of the presentations for just $25, or come to all three for just $60.

Entry requirements
Open to all

Each presentation – $25
Attend all three for just $60

Compressed Earth Block Workshop

Sunday, April 24, 2016
9.30 am – 5.00 pm
Cold Springs, Ontario

Instructors: Chris Magwood & Henry Wiersma

Workshop Description:

Learn how to work with locally-made, low-impact, durable compressed earth blocks (CEB, or rammed earth blocks) for foundations, exterior walls and interior walls.

CEB building is a low-tech building solution using basic materials and simple tools. Drawing on the age-old technique of rammed earth building, CEB uses a hydraulic press to create unfired earthen blocks.

CEB 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 see how an earth block press operates, and learn how to create a suitable rammed earth mix. You will learn how to mix a mortar suitable for CEB and how to lay up the blocks in a small wall project. Engineering and code approvals will also be covered.

You will be able to tour a completed earth block building with the CEB used for the walls and the floor.

At the end of this workshop, you will be ready to construct your own compressed earth block project!

Entry Requirements
Open to all

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

Maximum class size: 12

Light Clay/Straw Workshop

Sunday, April 10, 2016

Sunday, October 30, 2016
9.30 am to 4.30 pm
Endeavour Centre, Peterborough

Note: This workshop is being offered twice in 2016. Be sure to register for the correct date.

Instructor: Chris Magwood

Workshop Description:

Come and discover how a simple mix of low-cost natural materials can create a remarkable thermal insulation!

Light clay/straw (or slip straw or straw/clay) construction uses straw mixed with clay slip to create an insulation material with good thermal, moisture-handling and structural properties.

In this workshop, participants will learn about the components of straw/clay, see a slideshow of various Canadian and international straw/clay building projects, and gain an understanding of how, why and where straw/clay is an appropriate material choice. In the classroom, we will look at the costs, sourcing and building science of using straw/clay on new building projects and renovations.

In the hands-on component of the workshop, participants will learn how to assess the necessary materials and create a mix that is appropriate for a desired end use. We will use mixing machinery to create batches of straw/clay, and learn how to place them in a wall system. Different types of framing and shuttering (or forming) systems will be shown, and every participant will leave with a straw/clay block they cast themselves.

After this workshop, you will be able to undertake a straw/clay project of your own!

Entry Requirement
Open to all

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

The (Carbon) Elephant in the Room

There is an elephant in the room when it comes to our buildings, and it’s a carbon elephant… Every time we make or renovate a building, there is a carbon footprint as a result of the harvesting and manufacturing of the materials as well as the transportation involved. If we think this carbon footprint is negligible, we’re ignoring the elephant in the room!

Embodied carbon versus operational carbon
For many years, green building advocates maintained that the embodied carbon of building materials was not as important as reducing the operational energy use and carbon footprint. By this reasoning, it was justifiable to use materials with a high carbon footprint because they would eventually “pay back” that carbon “investment” with reduced energy use over time.

It’s not a trade-off
However, it is possible to make buildings with low-carbon building materials that match the energy efficiency performance of buildings that use high-carbon solutions. It’s a win-win solution… but it takes some adjustments to our way of thinking about buildings.

The carbon elephant
A comparison of the carbon footprint of a few different types of building shows that there can be a huge difference based on just a few material selections.


Carbon emissions of various construction types (from Making Better Buildings)


This chart shows the same 1,000 square foot house (based on the model house in the book Making Better Buildings). The two conventional approaches differ only on the choice of exterior cladding, one brick and the other vinyl siding. They have a carbon footprint many times larger than a best practice home made from low-carbon materials. But surprisingly, the straw bale home using lime-cement plaster actually has a carbon footprint slightly higher than a conventional home with vinyl siding. The same bale home plastered with clay has a dramatically lower carbon footprint.

Carbon sequestration
The carbon footprint numbers shown in the chart assign a carbon footprint to the cellulose materials (wood, straw, cellulose insulation), but don’t take into account the carbon sequestration effect of bundling a lot of carbon-based material into a building for a long period of time. There are conflicting notions of how to account for this, but at the very least there seems to be agreement that the sequestration completely offsets the carbon footprint. There is some reasonable argument to be made that these materials can actually have the effect of negating some of the building’s carbon footprint… that is, create a negative amount on the building’s leger. Things look different when this is taken into account!

Carbon emission footprint with sequestration of cellulose material at 25% of material weight

Carbon emission footprint with sequestration of cellulose material at 25% of material weight

By eliminating the carbon footprint for cellulosic materials and giving a sequestration factor of 25% of the total material weight, the carbon footprint can actually be put into the negative. However, those striving for carbon neutrality must remember that sequestration relies on the growth of new bio-mass to absorb CO2… we need to plant trees to replace those we’ve used in order to ensure these figures.

Carbon footprint as demonstrated by the number of carbon elephants emitted

Carbon footprint as demonstrated by the number of carbon elephants emitted

Different approaches not equal
The world needs carbon reductions immediately. Ensuring high carbon output today with the hope of a long-term reduction is a questionable strategy; it’s better to bank on getting our carbon footprint reduced now, especially if we can do so without sacrificing future reductions in the form of energy efficiency. When we start building very efficient buildings, the carbon footprint of the materials can start to equal many years of operating energy.

Carbon footprint by embodied carbon, 1 year and 10 year operational carbon for three climate zones

Carbon footprint of a foam-home, a high performance low carbon home and an older home, by embodied carbon, 1 year and 10 year operational carbon for three climate zones

This graph shows the embodied carbon of a high performance building using foam insulation, a best-practice low-carbon building and a largely un-insulated low-carbon building in different climate zones. Note that with best practice, there can be almost 10 years of operating energy before the building has the carbon footprint of a foam-based high performance house. And that’s without taking any sequestration into account! Obviously, we want to avoid the huge footprint of poorly insulated buildings, but ideally we want to do so in a low-carbon way. If we can build a low carbon home and use it for 7-8 years before we have the carbon footprint of a foam home, this is the option we should pursue!

No small effect
There were over 220,000 new homes built in Canada in 2014. Using conventional materials, these homes account for over 3 million metric tonnes of CO2 output. Using best low-carbon building practices can eliminate that altogether, and could even contribute 0.5 million tonnes of sequestration… more than 3.5 million metric tonnes of CO2 reduction!

Canada’s commitments under the Copenhagen Accord call for us to reduce about 127 megatons of CO2 given 2013 output figures. A move to building carbon-conscious homes could get us almost 3 percent of that target, in one industry, with little need for re-tooling or re-training of trades AND using materials that are harvested and produced in Canada. As a bonus, such homes are not necessarily any more expensive or difficult to build.

Kind of puts a positive spin on things, no?

What Makes a Building Product “Green”?

The Green Glut
The past 10 years have seen an explosion of building products being marketed to designers and builders as “green.” As the immense impacts buildings have on our planet’s ecosystem started to become clear to the mainstream building industry, marketing departments went crazy to identify just about every kind of product as being “green” in some way or another.



From my position as someone advising people on green building options, this “glut of green” causes a lot of confusion. If every product is green, what does it mean to really be green?

Real Green Criteria
In order for a product to meet Endeavour’s standard for green, it has to meet several criteria:

  • Must have low ecosystem impacts in the harvesting and production of the product. This includes considering both how and where the raw materials are extracted and handled, and what kinds of pollution/emissions happen during the production processes.
  • Must have low embodied energy and carbon footprint. This means understanding how much (and what kind) of energy is used to harvest and process the product and the size of the fuel and carbon footprint.
  • If applicable, the product must positively impact the long-term energy efficiency and/or performance of the building.
  • Should not use and definitely must not emit any dangerous chemicals or off gassing, during manufacturing, use in the home, or at end-of-life.
  • Must be durable, and have a reasonable end-of-life strategy (ie, where does it go when it’s taken out of the building).
  • Upcycled, recycled and re-purposed materials are preferable.
  • Local production is preferable to long-distance shipping.

Meeting Just One Criteria = Not Good Enough
Many building products are sold as “green” if they meet any one of those criteria. Unfortunately, the majority of building products sold as “green” fail (often miserably) when examined against all of these criteria. While the sales team will glowing focus on any glimmering of green in one category, rarely does anything with the green label come close to satisfying a full range of ecological criteria.

Living Products Expo

Living Products Expo

A Materials Revolution?
The dichotomy between products posing as green and those that are truly green was on display at the recent Living Products Expo, which I attended in Pittsburgh last week. Organized by the International Living Future Institute, the event was billed as “Inspiring a Materials Revolution.” And kudos to the organizers, because this really was the intention of the event.

What Makes Foam Green?
But at one point I found myself in a session that featured several product manufacturers presenting on their new green products. One was a rep from Johns Manville presenting a new polyisocyanurate foam insulation product that does not have added fire retardants (called Energy 3.E). Now this is an interesting achievement, since the flame retardants used in foam insulation are among some of the worst and most persistent chemicals in use on the planet, and up to 15-20% of flame retardant by weight is used in foams. The San Antonio Statement on Brominated and Chlorinated Flame Retardants should be enough to scare all of us away from using any products that use these flame retardants, so to have a foam insulation that eliminates them from its chemistry (without using questionable substitution) can be viewed as a major step, one worthy of the label “green.”

Johns Manville foamExcept that if we put even this insulation to the test of our criteria list, it still fails on many counts. The foam is still a petro-chemical product, and if we don’t like what the oil industry does to the planet (from exploration impacts to drilling sea beds or excavating tar sands to the vast amounts of energy consumed and carbon produced to spills and “toxic events”) then it’s hard to see any foam product as being green. Foam insulation has very high embodied energy and carbon output. It still uses questionable chemistry, has no end-of-life plan and is shipped long distances from a centralized factory. Energy 3.E might be “greener” than other foams, but I don’t think it can really be called green or sustainable. This despite the fact that the product has won all kinds of green awards and has been widely celebrated.

Ecovative mushroom foamReal Green Insulation
This point was driven home by the next presenter at the same session, this time from Ecovative Design. This company has developed “mushroom foam,” a material that is made from mycelium (mushroom roots) grown amongst agricultural waste fibers. Among its many uses, it can be made into an insulation product with very similar performance qualities as plastic foam. This material satisfies all of the stringent criteria we apply to products in our buildings, and it is naturally flame resistant (interestingly, it turns out that the phosphorus atom the Johns Manville scientists managed to insert into their foam occurs naturally in the mycelium). Unfortunately, Ecovative’s insulation products have not yet reached the mass market, while the foam product has. But the stark difference between the two is a perfect illustration of the difference between being “sort of green” and “really green.”Ecovative process

At the same conference, I gained a more in-depth understanding of two programs that are intended to help builders tell the difference between real green products and those that are just pretending to be green.

Cradle to Cradle products programCradle to Cradle Certification
The Cradle to Cradle Products Innovation Institute certifies products on a scale from “bronze” to “gold” based on their satisfaction of a wide-ranging set of criteria. The C2C Products Registry allows one to select a product category (such as Building Supply and Materials) and find products that have met their very high standards. I highly recommend this when searching for truly green products to use in buildings, though the overall number of products is still relatively small.

declare labelThe Declare Label
Declare is a labelling system introduced by the Int’l Living Future Institute. The Declare label is billed as “a nutrition label for the building industry.” It focuses largely on a transparent declaration of all the ingredients in a product, and where those individual components come from. The Living Building Challenge building certification program has a “red list” of chemicals that it does not allow to be in a building. This label is a means of finding out if a product contains a red list chemical, and what things it contains that may not be desirable even if it is not on the red list. Declare does not consider ecosystem impacts, carbon emissions or other elements of manufacturing, and so is not quite as comprehensive as Cradle To Cradle, but it is still a great development and a useful tool for builders looking at green in a deeper way.

Green Chemistry and Local & Natural
green chemistry principlesAs stated in the Living Product Expo’s desire to spark a “materials revolution,” there is a real move happening toward creating and using building systems that are truly better for the planet. John Warner, a founder of the “green chemistry movement” was a speaker at the Expo, and more and more material developers are starting to use the principles of green chemistry for the built environment. Having presented to the Expo about Endeavour’s methods for prefabricating straw bale wall panels, I found it interesting that the most promising sustainable building systems are relatively low-tech, use waste streams from other processes and are simple to replicate in smaller, regional “micro-factories.” Mushroom foam, straw bale walls, cellulose insulation and so many other effective, truly green materials don’t require major industrial apparatus. To a large degree, this is what makes them truly green. Keeping it simple, local and natural is often the best way to ensure it’s green!