Building bottle wall features

how to build a bottle wall

Many natural buildings feature bottles incorporated into walls. Bottle walls add colourful light and whimsy to a wall and open up all kinds of great design possibilities.

Here’s a little “how-to” guide to building your own bottle wall. It’s quite an easy process, and is applicable to interior walls and renovations as new buildings. Your own creativity is the only limit when it comes to using bottles in your building!

Workshop survey for 2015

Endeavour tries hard to program workshops that are of value to those interested in sustainable building. This year, we’re looking for your help with our 2015 programming!

We’ve created a very short survey to give our readers input on the types, locations and costs of our workshops. We hope you’ll participate!

By filling out the survey, you’ll be entered into a draw to win an Endeavour workshop gift certificate.

You can find the survey here.

Canada’s Greenest Home uses 71% less energy!

Canada's Greenest Home

We set out with some pretty lofty goals for our Canada’s Greenest Home project. The idea was to use only the healthiest, most ecologically friendly building materials and use them to create a home with outstanding energy performance. And we wanted to do it in a way that would be cost-comparative and easily achievable for other contractors. We finally have the data to show our results on the energy performance side.

From modelling to the real world

Much is made during the design process of “green” homes of energy modelling figures and estimates of consumption and/or savings based on the design. However, in few cases do we ever get to see an accurate portrayal of the actual consumption figures as compared to the models.

Obtaining real-world performance data was one of the key reasons we wanted to spend at least a year living in Canada’s Greenest Home. And now that we have been living here for a year, the results are in!

Energy produced compared to energy used at Canada's Greenest Home

Energy produced compared to energy used at Canada’s Greenest Home

Canada’s Greenest Home components

To recap, the home has a 5kw PV array, that is grid-tied using Ontario’s MicroFIT program. This means that there are two electricity meters on the house, one recording power going out to the grid via MicroFIT, and one recording power coming into the home. These figures allow us to see a clear picture of our consumption versus our production. There is no other fuel source in the home, as our heating system is powered electrically, via a Mitsubishi Zuba air source heat pump.

The results!

Our total annual consumption (including heat, refrigeration, cooking and all other plug loads) was 8,867 kilowatt hours, and our total production was 6,075 kilowatt hours. So we were 2,792 kw/h short of being net zero energy. Some of this can be attributed to the fact that the winter of 2013/2014 was quite a bit colder than average, and ice covered our panels for much of January and February (the output numbers are typically higher than December, but are quite a bit lower). In a different year, we would be quite a bit closer to net zero.

Financially, the picture is quite rosy. At our MicroFIT rate of 54.9 cents per kilowatt hour, our earnings from the PV system were $2,028.07 higher than our utility costs. Not many homes earn money for the owners, rather than costing them! That surplus goes a long way to putting a dent in the mortgage costs.

Comparing to other homes in Ontario

Comparing our energy usage to averages for Ontario (using the most recent StatsCan figures) is also illuminating. The average home of this size (2,000-2,500 square feet) built since 1996 uses 107 gigajoules of total energy (GJ is used to be able to compare measurements between different fuel sources like natural gas, oil, and electricity). Converting our kilowatt hours to gigajoules shows that we used 31.92 GJ, or just under 30% of the comparable average home! By square meters, we used 0.15 GJ per meter squared of floor area.

Passive House modelling slightly off

Interestingly, the energy modelling done in the Passive House software (PHPP) showed that our heating demand should have been 11,529 kw/h for the year, but our total usage including all non-heating loads was 8,867 kw/h, a substantial difference. As a guess, I would say that it is low R-value figures given for straw bale walls that accounts for this difference. Tested R-values and real world performance are always different beasts, but seem to be even more so for straw bale wall systems.

Doing better isn’t hard

We are very proud of these results. Considering that the costs for the shell of the home were very comparable to “conventional” construction (the majority of our additional costs were for mechanical systems like rainwater harvesting, composting toilets and solar hot water, as well as the PV), it bodes well to show that with small, achievable, and affordable changes in construction, vast improvements in performance can be achieved.

In our case, these improvements were made using locally-sourced, low-impact and mostly renewable resources, showing that eco-friendliness has many facets, and that being good for the planet when choosing materials can also mean being good for the planet in long-term impacts.

Anybody can build a home like this, with very low environmental impacts and great performance. The question is, why don’t more people do it?

Rocket mass heaters with Andrew Brunning

how to build a rocket mass heater

I have lived almost my entire life in homes that have been heated with wood in one way or another. From a giant wood furnace in the basement of an old Ontario farmhouse to an elegant little pellet stove in a city home in Peterborough, I have enjoyed the process of burning wood to keep warm.

Rocket stove revolution

With this kind of background, it’s no wonder that I have followed closely the development of “rocket stoves” over the past decade. From their beginnings as a means to provide efficient cooking heat from minimal fuel in developing countries, the promise of rocket stoves has been intriguing for any wood burning enthusiast. However, the open “J-tube” style of most rocket stoves meant that the feed tube for the fire was open inside the home with all the attendant dangers. In addition, the wood used in J-tube stoves is small dimension, which is perfect for cooking where fuel is scarce but as a home heating device means constant attention and stoking is required. For these reasons, I have been hesitant to recommend rocket stoves as a home heating system, except for the strong-hearted devotees of the idea.

Rocket mass heaters – suitable for indoors!

However, the development of “rocket mass heaters” brings the rocket stove idea to the point where it is a feasible home heating device. This style of rocket stove blends the safety and efficiency of the masonry heater with the do-it-yourself approach of the rocket stove. I was privileged to be able to take a workshop on building rocket mass heaters with Andrew Brunning of Rocket Mass Heaters.

The design of the rocket mass heater, or batch box rocket stove, was developed by Peter van den Berg, and its genesis is explained in this article in Permies. The heater combines the simple construction and burn characteristics of a rocket stove with a full masonry burn box, as with a masonry heater or typical wood stove, which can have a closed door with or without glazing. One fill of the burn box equals several hours of burn time and many more hours of heat from the mass built around the stove.

How to build a rocket mass heater

The workshop with Andrew allowed the participants to help build the rocket mass heater, as well as the large mass bench that would be the recipient of the heat generated. The photo gallery below gives a good overview of the process:

Rocket mass heater workshop coming to Endeavour in 2015

I look forward to building one of these rocket mass heaters for myself. And Endeavour looks forward to bringing Andrew to the school in 2015 for a hands-on workshop!

How to build with earthbag

earthbag, earthbag foundation, earthbag workshop

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!

Goodbye to the class of 2014

The students of the Sustainable New Construction 2014 class said a belated goodbye to Endeavour and the teachers’ union office project.

Their departure was one month later than expected, as five of the seven stayed on through October to make up for time lost during permitting issues earlier in the summer.

The last week was about adding some fun finishing details to the building, including the cordwood entryway to the meeting room and some great bottle and hempcrete transom details in the doorways.

This was an amazing group of builders, and we wish them all the best as they move onto their new lives in the sustainable building world!

Thinking about sustainable building

There is a remarkable paradox when it comes to introducing new technologies, in construction or any other field. We expect new ideas or technologies to live up to unrealistically high standards, while at the same time we accept as normal many existing ideas or technologies that are inherently, deeply flawed.

It is a commendable tendency to try and be “objective” about new ideas and weigh as much evidence as we have at hand in deciding whether or not we think they are worthy. But we tend to be much less than objective about the ideas and technologies we use on a daily basis. Because they are normal to us, we rarely examine them in any meaningful way. A certain degree of inevitability is attributed to the ideas we’ve normalized; we don’t see them as choices in the same way we see new ideas as choices.

There are countless examples of this paradox in everything we do. In the building world, we find a great example in the use of milled lumber as our prime residential building material. Wood has every flaw imaginable for a building material. It burns; it rots; it’s insect food; it warps, twists and cracks; it’s a great medium for growing mold; its structural properties vary greatly by species, milling, drying and storing practices; it’s often grown far from where it’s needed; it’s heavy; it’s dimensionally unstable as climatic conditions change…. In fact, if an attempt were made to introduce wood as a building material in today’s building code climate, there is little chance that it would ever be approved!

And yet milled lumber has come to serve us very well as a building material. Collectively we used a natural material that was available to us and figured out how to deal with all its “micro-flaws.” In the end, we’ve normalized it and built an entire successful industry around an entirely flawed material! But if we introduce a new material that has even a small number of the flaws inherent in wood, we find ourselves up against naysayers who can only see the flaws and not the possibilities for being able to work with them. Straw bale and earthen building techniques can have many fewer flaws than wood construction, and yet are subjected to much more scrutiny.

There is no such thing as an idea or technology with no flaws. Recognizing this simple point is key to being able to consider new ideas fairly. There is an experiment I perform at public talks: I ask the audience how many of them have had to deal with a toilet backup at some point in their lives. The show of hands is almost guaranteed to be unanimous. Then I ask that same audience if they think the flush toilet is a bad, flawed idea that ”doesn’t work”; very few say Yes. And this despite having to regularly deal with some very unpleasant consequences due to an inherent flaw in the technology! We accept the micro-flaw of an occasional toilet backup as a reasonable trade-off for the convenience of using a flush toilet. However, I hear frequently that composting toilets “don’t work” based on second-hand reports of a single incidence of the composter smelling or not composting properly. There’s the paradox: the “normal” technology fails disgustingly at a rate of almost 100 percent, and yet the “alternative” is the one that gets branded as something that “doesn’t work.” In truth, both systems have some inherent flaws, and both will fail on occasion. We’ve just learned to accept the micro-flaws of one and reject the micro-flaws of the other.

Can composting toilets work? It's a question worth putting your head into!

Can composting toilets work? It’s a question worth putting your head into!

 

Every new technology a homeowner will examine when making choices has a number of micro-flaws, as do those conventional technologies they might replace. One should not attempt to gloss over any micro-flaws, as you will be living with them for a long time. But the comparisons between sustainable technologies and their conventional counterparts do not and cannot stop at the level of micro-flaws. Sustainable building strives to address the larger and much more important macro-flaws in our approach to building.

It is at the macro level that all of the materials in this book have their advantages over conventional practices. To continue the comparison between flush toilets and composting toilets, we can see that both can be practically functional but also have some micro-flaws. On the macro level, however, the flush toilet is part of a system that sees billions of gallons of untreated or partially treated sewage enter our streams, rivers, lakes and oceans, while using vast amounts of clean potable water and a very expensive public infrastructure. Meanwhile, composting toilets can turn human “waste” into a valuable fertilizer with minimal infrastructure and little to no fresh water usage. It is at this macro level that we should be assessing our building technologies. In this case, the advantages of the composting toilet should be very clear.

Sewage report card

If we can start making wise choices at the macro level, we can trust ourselves to figure out how to minimize the micro-flaws of any technology. We humans are incredibly good at refining ideas and techniques. Through repetition, we gain insights that allow us to make the process better and better each time we use it. We’re good at doing things better, but we’re not very good at doing better things. Doing better things means looking beyond the micro-flaws and basing our choices on minimizing impacts at the macro level.

One of the challenges in adopting any new technology is figuring out where we are on the learning curve, and at what point on that curve we feel comfortable jumping on board. Some of the systems we work with in sustainable building are quite well developed, with installation and maintenance instructions that are very complete and manufacturer and installer warranties that back them up. Others are relative newcomers (at least in the modern context) and the instruction manuals are literally being written and refined right now. We may not know the very best way to use some of these systems until a lot more early adopters have trial-and-errored their way to some kind of standardized practice. There are rewards to helping break new technologies, and also risks.

Figuring out what choices to make in a sustainable building project can be overwhelming. It requires a lot of level headed research, a willingness to question in cases of 2G2BT (too good to be true), and a clear understanding of your goals and your budget. Endeavour’s Plan Your Own Sustainable Home workshop is a great way to start sorting out all these choices for yourself!

(This blog is adapted from the book Making Better Buildings: A Comparative Guide to Sustainable Construction)

Making Better Buildings book by Chris Magwood

Making Better Buildings by Chris Magwood

Building with Hempcrete or Hemp-Lime

hempcrete building workshop at Endeavour

A group of lucky participants was treated to an excellent weekend workshop on building with hempcrete (or hemp-lime), led by UK architect and hempcrete pioneer, Tom Woolley. Tom is the author of Hemp Lime Construction and Low Impact Building, and has been involved in many hempcrete and sustainable building projects throughout the UK.

The weekend began with a classroom session, during which Tom covered the materials and techniques for successful hemp-lime building, and showing the group photos and details of a variety of building projects, including his charming hemp-lime cottage.

We then moved on to making some sample mixes to demonstrate the combination of materials. We were working with two different mix types, and made a sample of a third type of mix. For all three mixes, the weight ratios of materials were the same:

  • 1 kilogram of chopped hemp hurd (also known as shiv)
  • 1.5 kilogram of powdered binder (natural hydraulic lime or hydrated lime and metakaolin)
  • approximately 1.5 kilograms of water

The chopped hemp hurd or shiv needs to be fairly course (particle sizes ranging from 1/4 to 1 inch) and be relatively dust- and fiber-free. We were able to source Canadian-grown and processed hemp hurd from Plains Hemp in Manitoba.

Most UK-based hempcrete builders work with a natural hydraulic lime (NHL) as the basis for their binder. There is no North American source for NHL, so it tends to be expensive to import from Europe. We used an NHL 3.5 from St. Astier as one of our mix options. For a more locally-sourced version, we used a typical North American hydrated lime and a fired kaolin clay (called metakaolin) called Metapor. The NHL is a lime that chemically sets (hardens) through a reaction with the water content of the mix. North American hydrated lime does not set hydraulically (with water), but when mixed with a pozzolan like Metapor the two materials together have a hydraulic set.

The dry ingredients (hemp hurd and lime) are mixed together so that the powdered lime is covering all of the hemp, and then the water is introduced. Having done some work with hempcrete at Endeavour, we were surprised at how little water Tom uses in his mix. The final mix is just moist enough to lightly hold together when squeezed in a hand.

With some small scale mixes placed into test cones, we then moved on to installing hempcrete in some larger wall panels. These panels were built by Sarah Seitz for her PhD research work at Queen’s University, where she will perform tests to help determine the thermal insulation properties of hempcrete.

The panels simulate a typical double-stud construction, with a 2×4 frame on the “exterior” side of the panel and a 2×3 frame on the “interior” side.

As one group mixed batches of hempcrete in the mortar mixer, the others placed it into the forms and lightly tamped it into place. As the forms fill up, they are moved up the wall. The hempcrete retains its shape after less than 20 minutes in the forms. The filling and tamping continues right to the top of the wall. Once everybody was settled into their roles, it took less than 1.5 hours to fill a whole wall form.

In the end, we placed 40.25 cubic feet of hempcrete into the two walls. We used seven 40-lb bags of hemp hurd and seven bags of powdered ingredients to reach that quantity. With the small amount of water used in the mix, we’re anticipating a drying time for the 14-inch thick walls of about 2 weeks. This is much shorter than for the wetter mixes we have made in the past.

Cost-wise, we used $63 of hemp, $42 of hydrated lime and $21 of metakaolin, for a total material cost of $3.13 per cubic foot of insulation.

We will share Sarah’s thermal testing results when she has completed them. We are expecting to find their performance to be around R-2 to 2.5 per inch, meaning that our 14-inch wall would surpass current code requirements for thermal insulation.

This was a fun and informative workshop, and we’d like to thank Tom Woolley for sharing his deep knowledge of this subject with us!

Finishing the straw-cell wall system

Straw cell wall system

Our office building project for the Trillium Lakelands Teachers’ Union features a straw bale wall system that combines conventional wood stud framing with an interior straw bale wall.

Recently, we finished the exterior side of this wall system. This involved placing dense-packed cellulose insulation in the frame wall, filling the cavity so the insulation is blown tightly against the straw bales. With the cavities insulated, we add approximately R-21.5 to the R-30 of the straw bales. Our contractor for the dense-packed cellulose was Morgan Fiene at New Energy Consulting in Hastings, Ontario (705-313-2004), whose care and concern for doing a thorough job was very refreshing.

We then covered the framing with an insulative wood fibre sheathing. This 1/2 inch wood fibre sheathing has an R-value of 4 per inch, and is made from 100% recycled wood fibre and a non-toxic binder. Made by Western Louisville Fiberboard in Quebec, this product is the cleanest sheathing product we could find. Most exterior wood fibre products use an asphalt emulsion coating, but the SONOclimat product uses a proprietary coating that is water based, non-offgassing and meets stringent environmental standards.

As a means to blend conventional wood framing with straw bale walls to achieve very high insulation values, we have been very pleased with the straw-cell system. It marries low impact materials throughout (earthen plaster, straw bales, cellulose insulation, FSC framing and recycled fibre board) with high insulation value and a straightforward construction process. It’s a great way to marry the more unconventional approaches to sustainable building with mainstream approaches.

 

Air tightness details for straw bale walls

Straw bale wall details

Straw bale wall systems have been touted for 20+ years now as a way to achieve higher insulation values with lower environmental impacts. And, having built many straw bale homes and commercial buildings now, we know this is true. However, we have also seen that without attention to air sealing details, many straw bale buildings are quite leaky and fall short of their potential level of energy efficient performance because of this.

Along with many straw bale compadres world-wide, we’ve worked to come up with details that address these issues of air tightness in straw bale buildings. Our latest project for the Trillium Lakelands Elementary Teachers’ Local offices have good examples of easy ways in which a bale wall can be built to be air tight without reliance on whole-wall vapour barriers or other sheet membranes.

Plastered straw bale walls have a naturally air tight nature thanks to the continuous plaster coating. Any crack-free layer of plaster does an excellent job of stopping air movement through a wall. However, where plaster meets other materials (at the top and bottom of each wall, at each door and window opening and around through-wall vents and pipes), just plastering up to these seams does not create an air-tight barrier. All plaster types share the characteristic of shrinking as they dry or cure. Every edge of a plaster wall will pull away and leave a gap as the plaster shrinks. It may not seem like much, but even a 1/16 inch gap at the top of 100 feet of wall area is the equivalent of 75 square inches of “hole” in the wall! Add that same gap around every window and door and at the bottom of each wall and you may have a hole in your wall of up to 1.5 square feet! That’s like leaving an average sized window open full time!

Most homeowners understand that having a window open all winter long would have a negative affect on the amount of energy used to heat the home. But many people do not put the time and effort into “closing the window” around the perimeter of their straw bale walls.

For some, there is a reluctance to build air-tight because of a notion that it is unhealthy to seal a house “too tightly.” However, it is also unhealthy to be drawing outside air into your home through cracks and leaks in your walls. That infiltrating air picks up dust, spores, and anything else that is in the walls on its way into the house. Seal the house properly, and deal with the ventilation that is required in an intentional, clean way.

It’s not difficult to make an air tight bale wall. We will report on our blower door test results for this building as soon as we have performed the test!