Canada’s Greenest Home at 136 1/2 James Street, Peterborough

Canada’s Greenest Home is about to go on the market, and as we switch out of construction mode and into the process of selling the home on its merits we figured this is a good time to reflect on whether or not we’ve met our goals.

Not a Competition

We were initially quite hesitant to brand this project as “Canada’s Greenest.” The claim was not made to be boastful or to dismiss the work of other designers and builders who have made remarkably green homes. The sustainable building community is very “open source” and cooperative, and definitely not competitive. But we were very interested in pushing as many boundaries as possible with this project, to challenge ourselves as designers and builders to make the very best house possible, going beyond what has been done previously.

Our Goals

We had a very well defined set of goals going into this project, and the sum of these goals, we felt, would result in the greenest home in the country. Here is our self-graded report card:

Extremely high energy efficiency

• The annual heating bill for the home, as determined by energy auditor Ross Elliott of Homesol Building Solutions, will be around $325 annually.
• The home will have net zero energy use if the occupants have “average” power usage habits, and the photovoltaic panels will provide an income for the homeowners.
• We achieved a very high degree of air tightness, with the final test showing 0.63 ACH/50 (air changes per hour at a 50 Pascal pressure differential).
• An Energy Recovery Ventilator (ERV) supplies fresh, filtered air with minimal losses of heat and moisture from the building.
• A complete energy monitoring system with central touch-screen display will assist the owners in meeting their own energy consumption targets. A smart phone can monitor the system from anywhere in the world.

Extremely high indoor air quality

• Every finish and surface in the home meets the highest standards for being chemical free and non-toxic. Achieving this level of non-toxicity was a great challenge, and one we’re proud to have met.
• The air handling system has the best filtration system available, and the owner can control fresh air exchange with simple controls.
• Occupants with chemical sensitivities should find the home to be a very welcoming environment.
  

  Living room with south-facing windows and clay plaster walls

All materials manufactured and sourced as locally as possible

• There are many green building products available in other markets (Europe, in particular, leads Canada in this way), but we wanted to avoid importing solutions and meet our targets using only materials from within a 250km radius. For all the major components of the building, we were able to achieve this goal. This keeps transportation energy costs and impacts minimal.
• The market makes achieving this goal very difficult. Outsourcing to less expensive labour markets means that some categories of products are no longer manufactured in Canada, or even in North America.

Very low embodied energy materials

• We chose materials with the lowest possible harvesting and manufacturing impacts. By choosing materials like straw bale walls from NatureBuilt Walls and recycled cellulose instead of petrochemical foam insulation, we are able to greatly reduce environmental impacts to a fraction of a conventionally-built home’s footprint.

Very low water use, with the potential to be water self-sufficient

• The rainwater collection and filtration system is designed to allow the homeowner to be water-independent. Connection to the municipal water service gives the homeowner the choice to use rainwater for all or just selected uses.
• All plumbing fixtures in the home have the lowest possible water usage rates.
• Composting toilets use 0.1 liters per flush, rather than the industry best 4.0 liters per flush.

No sewage output

• A complete composting toilet system is one of the most distinguishing features of this home. By eliminating sewage output, the home dramatically lowers its environmental impacts, and by creating useful compost the toilet actually becomes a generative rather than a destructive feature.
• The foam flush toilets provide the homeowner with a very low maintenance and “normal” toilet experience.
• The home sends its grey water to the municipal waste water system rather than dealing with it on site. This was our one major area of “compromise,” with regulations, cost and practicality leading us to decide that the small amount of relatively clean water output would go to sewer.

Zero fossil fuel usage

• An air source heat pump (ASHP) provides heating and cooling with no fossil fuel use.
• Solar panels provide all of the home’s electricity needs. When the solar power is not available, a contract with Bullfrog Power ensures renewable energy is still meeting the home’s needs.

Very low construction waste

• By choosing low-waste building materials and carefully re-using, re-purposing, sorting and weighing our leftovers, we were able to send only 852 lbs to landfill, versus 10,000 lbs for an average home of the same size!

Make a Reproducible Home

• We did not want this home to be a “one-off” specialty home. Any contractor or homeowner can reproduce the results of this home with materials and products that are off-the-shelf.
• We intentionally did not choose materials or systems that would require skills, sourcing or maintenance that are outside the scope of any builder or homeowner.

Make a Home with “Street Appeal”

• While aesthetics are a highly personal matter, we wanted to create a home that fit into an existing neighbourhood. The exterior is intended to be attractive without being “showy.”
• The interior finishes are intended to bring a natural building slant to contemporary design, mixing clean lines and open spaces with natural materials and surfaces. Retraining and retooling is not required to build a home like this.
  

  Clay paint on a prefabricated straw bale wall

High educational value

• Endeavour Centre students, who will hopefully take what they learned into the marketplace and assist with building more homes like this one, built the home.
• Our construction blog has attempted to document the process of building the home, sharing our experiences, sources and lessons learned.
• Open houses and post-construction documentation will make this home as open source as possible.

Prove that the market will support green building

• The home was funded by a private investor as a “spec home,” with no government grants or other incentives.
• Placing the house on the open market will hopefully show other builders that there is an appetite for homes of this type. We believe that the market is changing and that owners are willing to invest in a home that has very low operating costs and a high degree of resilience, and which makes their health and well being a priority.

Guidelines and Criteria

We used two green building rating programs to help guide us. LEED for Homes offers mainstream builders an excellent tool for measuring their environmental performance and reaching for higher targets. We aimed to exceed the requirements to meet the LEED Platinum standard, and are well on our way to being certified with a points score well in excess of the Platinum requirements.

The Living Building Challenge is the most stringent construction standard we were able to find, and within its guidelines we found plenty of inspiration. In following the Living Building Challenge we definitely stretched our abilities and understanding and elevated our practice. Certification under the LBC can only happen after one year of occupation, so it will be up to the homeowners to continue to meet the challenge.

No Prescribed Solutions

Despite following two great standards, there is no one-size-fits-all solution to building green. We deviated from some recommendations and requirements of both programs in order to pursue solutions we felt were more appropriate for this project.

We Think We Did It!

There is no reward or prize at the end of a process like this beyond the satisfaction of achieving a professional pinnacle and meeting one’s own very high standards. We anxiously await the buyer who will recognize this achievement and work with us to commission the home in a way that ensures it meets its substantial promise.

As designers and builders, we have learned a tremendous amount from this project, and look forward to applying those lessons to future builds. We also look forward to the day when a home like this is the norm, rather than far exceeding the norms. This type of home building on a large scale would have significant and measurable positive impacts on our environment.

In the province of Ontario in 2002, “1.2 million tones of solid waste were generated from the construction and demolition sector” (Development of Construction and Demolition Waste Recycling in Ontario). A typical home construction project will generate about 8,000 pounds of solid waste per 2,000 square foot home according to the National Association of Home Builders.

The Canada’s Greenest Home project is attempting to seriously limit the amount of material sent to landfill from our construction site. Reuse, recycling and diversion are taken very seriously on this project. To date, we’ve only sent 852 pounds of waste to landfill, and have diverted 3537 pounds to reuse, recycling or other end uses. That is about 10% of the provincial average!

We’ve managed to reduce overall waste to the point where our largest quantity of material going to landfill is floor sweepings! Each time we sweep up inside the building, we pull out any fasteners or recyclable materials before bagging up what’s left. But that dust and debris can weigh a lot, especially after sanding the drywall taping. Our most recent trip to the landfill included 146 pounds of waste, most of which was accumulated floor sweepings. Sawdust, dirt and dust can really add up! We could conceivably bury this material on site, as it’s quite inert. But we wanted to keep an accurate measure of what we “produced” that couldn’t otherwise be reused or recycled.

All material leaving the site was weighed and tracked.

With landfill tipping costs still artificially low (that is, taxpayers subsidize landfill costs for builders), there is little incentive to reduce job site waste. If municipal governments were to charge appropriately for access to landfill, builders would save money by diverting waste to other streams. In the meantime, it’s not difficult to achieve the significant reductions we’ve managed on this project. Placing appropriate bins on site and labelling them well is the biggest step, followed by designating someone on site to manage waste. Buy-in from subcontractors is important too.

Even minimal improvements on conventional building sites could seriously reduce landfill use. We hope this project sets a high bar for what is possible when it comes to construction waste management.

Red wall almost finished

Natural clay finish plasters add an unparalleled beauty to any home, and it was exciting to apply these plasters to Canada’s Greenest Home this weekend.

These skim coat plasters can be applied over any wall surface. In this project, we used them over clay base coat plasters and over drywall.

The plasters are mixed on site using widely available and affordable materials. Clay, sand, calcium carbonate, pigment, flour paste and water are mixed together and applied to the wall by trowel in a single, thin coat (~1/8 inch).

Our typical formula is 10 parts clay, 4 parts sifted sand, 1 part calcium carbonate, 1 part flour paste (a natural glue/hardener) and ~3.5 parts water. Natural pigments are added to this mix by weight, based on trial samples made in advance. As with baking, the dry ingredients are mixed together and then added into the water, flour paster and pigment that have been blended.

The clay in this case is Tile 6 Kaolin, from a pottery supply store. We’ve used other kaolins and ball clays with similar results. Calcium carbonate is finely ground limestone, from Omya in Perth, Ontario. Flour paste is cooked by boiling 4 parts water and adding a mixture of 2 parts cold water and 1 part flour and boiling until thick. Our natural pigments come from Kama Pigments.

Helping us with the mixing and application was our good friend Mike Henry, a plasterer with Camel’s Back Construction. His attention to detail helps bring out the best in the clay plaster.

There is nothing like the depth, richness of colour, sound attenuation and warmth of a natural clay finish plaster!

Join us on Saturday, March 9, 10am – 4pm!

Canada’s Greenest Home nears completion

 

Clivus Multrum composting toilet tank

The Clivus Multrum composting toilet is one of the most important systems in Canada’s Greenest Home, and company representative Don Mills came up to Peterborough recently to help us with the fine points of the installation.

As mentioned in a previous post, treating human “waste” as a valuable and important resource instead of allowing it to become a sewage problem is an important step in the move toward more sustainable housing.

Now that our composting toilets are ready to be commissioned, it’s a good time to look at how this particular system works, and why we chose this type of toilet system over others.

There are three basic categories of indoor composting toilets. The first – and by far most simple and affordable – is the bucket toilet. We at Endeavour love the bucket toilet, and recommend it highly for its low cost and effectiveness, but it was not a choice for a spec home! A step up from the bucket toilet (in price and acceptability, if not performance) is the self-contained composter. These toilets feature toilet and compost tray together in one unit. These can be effective in situations where usage is light, but do not have the capacity to handle the daily use of a whole household. In order to try to “speed up” the composting process in these systems, heat is often used to evaporate urine and accelerate the decomposition of the solids. But by getting rid of the urine and making the solids dry and warm, a great deal of the valuable nutrients are wasted.

The final type of composter is the remote chamber style. These toilets have a large storage bin able to accept input from multiple toilets. The Clivus Multrum system is designed to make sure that composting takes place in the best possible environment, resulting in the recycling of the maximum amount of nutrient value.

Illustration of the Clivus Multrum composting system

The main tank for the Clivus Multrum system features a sloped base, with fresh deposits entering at the rear end of the tank and pushing older material forward. Once the system is established, there is a large bed of material in the tank. It is a mixture of solids, toilet paper and wood shavings. In this way, the Clivus system is like many others.

Two aspects really set the Clivus Multrum apart. First, the system captures all of the liquid and makes it accessible as a fertilizer. The urine that is collected has percolated through the composting bed, providing benefits to the solid compost as it passes through and changing in chemistry (to nitrites and nitrates) to become an excellent fertilizer with none of the potentially damaging effects of straight urine. This liquid is collected at the front of the tank and pumped into a separate holding tank. From here, it can be applied directly to gardens and lawns.

The vast majority of valuable nutrients that can be retrieved from human waste are found here, according to Don Mills. Simply diverting and/or evaporating urine is to waste a valuable resource.

The second unique feature of the Clivus toilet is the moistening system. The tank includes a sprayer and controls that mist the compost pile regularly with a small amount of water. This provides the ideal conditions for effective composting: not wet, not dry, but consistently moist. Having provided sufficient nutrients, aeration and moisture, the rich colonies of bacteria, protozoa, rotifers, actinomycetes, fungi, mold, yeast and earthworms can best go to work converting solid waste to useful compost. Dry compost material needs to be removed from the tank about once a year.

When fully functional, the toilet will require monthly attention, to mix in wood shavings. The liquid fertilizer can be pumped directly to gardens or transferred to containers to take it elsewhere.

In an upcoming post, we’ll look at the unique foam flush toilets that are the other unique feature of this system.

One of the most important features of Canada’s Greenest Home will be the use of nothing but non-toxic finishes for every surface in the home. Many of these will be home-made from natural ingredients. These non-toxic finishes will go a long way in ensuring that the home has a high level of indoor air quality, rather than the polluted air of most conventional new homes.

Natural finishes are an exciting part of this project because they are the most easily reproducible sustainable building element that a homeowner can apply to any new housing or renovation project. We hope the ideas and recipes we’ll post here will encourage more people to use natural finishes.

The whitewash we have used on the pine ceilings on the main floor of this home are a great example of a natural finish that is simple to make, non-toxic, durable and beautiful. Whitewashes have been used for centuries on wood and masonry surfaces, and bring a clean brightness to a room without affecting the moisture storage capability of the material or introducing any VOCs or petrochemicals to the building.

The whitewash recipe we used to achieve a semi-opaque whitewash on bare pine wood is:

1 part Casein powder
12 parts water
16 parts powdered hydrated lime

The water and casein were mixed 2-12 hours in advance and allowed to sit. The lime powder is then slowly added while stirring in a bucket with a drill mixer. The mixture will have some tendency to settle, and should be stirred frequently during application to ensure an even opacity. 1 gallon covers approximately 500-750 square feet per coat. We apply two coats to ensure an even coloration.

The amount of water can be varied to make a thinner or thicker paint, and pigment can be added to give tints. Without pigment, the colour is a bright white.

If powdered casein can’t be obtained easily, a similar recipe that will give good results can be made by mixing:

1 cup skim milk
90-120 grams of powdered hydrated lime

A good quality whitewash brush or thick paint brush with natural bristles will do the best job for applying this paint. On flat surfaces a roller could be used, but our V-groove ceiling required a brush to get into all the grooves.

This paint works so well because the casein molecule contains a powerful glue that is released when it reacts with the base nature of the lime, cracking open the casein molecule and allowing the glue to become a binder that securely bonds to the wood and the lime.

More natural finishes will follow!…

The Sierra Legal Defense Fund’s Sewage Report Card for Canada says “Over one trillion liters of primary or untreated sewage is collectively dumped into our waters every year by cities evaluated in this report (of 21 Canadian cities). This volume would cover the entire 7800 kilometer length of the TransCanada Highway to a depth of nearly 20 meters – six stories high.”

With this in mind (and remembering that this statistic is only counting large cities, not smaller cities, towns and individual homes), it is not possible to think about building a so-called “green” home if that home is contributing to this huge environmental problem.

However, unlike many other environmental issues that are complicated and difficult to address, this one can be handled quite simply: We need to compost our own human excrement. The process is not difficult, and there are solutions that range from the simple and inexpensive (see The Humanure Handbook for the $20 solution) to the more expensive – but still remarkably simple and affordable – chamber-style composting toilet as installed in our Canada’s Greenest Home project.

The bottom of the holding tank for the Clivus Multrum M10 composting toilet.

This is the only time you’ll catch me inside the composting toilet tank!

We started the installation of our Clivus Multrum M10 composting toilet unit today, and we’ll cover that installation in more detail as it progresses. But this is not just a “flashy” green addition to the home… we consider this one of the most important features of the home. Not only does it remove this home’s black waste from the atrocious statistic above, but proper composting of human waste creates useful and nutrient-rich soil amendment. At a time when we can ill afford to pollute more fresh water and when soil depletion is a real and growing problem, the composting of human waste provides a win-win solution.

When asked at workshops and public presentations what the one biggest “green” improvement somebody can make to their home, my response is always to move to composting toilets. It’s not a popular answer. We don’t like to think about our own excrement, let alone contemplate dealing with it.

But it’s not as yucky as most people would think. Dealing with a dog’s waste with your hand in a plastic bag is much more visceral and disturbing than dealing with a well-managed composting toilet system, and millions of people have been “trained” to pick up after their dogs. With that in mind, it’s not hard to imagine a future in which turning our own waste into useful compost is socially acceptable and expected.

This woman picks up her dog’s poo with her hand in a plastic bag! Can we be trained to deal with composting toilets?

At 0.99 ACH50, we broke the magical (in our minds!) 1.0 barrier. This is a very air tight home!

After our somewhat disappointing blower door test last week, we threw some mud at the walls (well, we placed it carefully around the edges of the wall), did some taping and caulking, and then had Ross and Kat Elliott of HomeSol Building Solutions come by to do our official blower door test.

We went from a code-compliant 3.1 ACH50 (air changes per hour at 50 Pascals) to an almost PassiveHaus compliant 0.99 ACH50! We could feel some small areas of leakage to be addressed (almost all were failures of the Tuck Tape to properly adhere and seal against the air barrier membrane!). After the test, we realized that we hadn’t covered over the sump pit in the basement, and so we think we can do even better on the final test once the house is finished. Ross suggested that it’s common to improve the air tightness by around 20% once all the interior wall and ceiling sheathings are in place.

Even if we end up slightly shy of the 0.6 mark, we are very excited to have built a house that far surpasses the air tightness of conventional building, and to have done that using mostly straw bale walls and even clay plasters. It’s an indication that the use of natural building materials and “alternative” methods can be part of an extremely tight and energy efficient building.

Our thanks to all the students whose constant awareness and vigilance regarding air tightness as we built the house helped to ensure that this result was possible. Way to go, Graham Wise! And our thanks to Matt Caruana for last week’s test… we wouldn’t have achieved this score without a first kick at the can!

As those of you who’ve been reading this blog will know, we’ve worked hard to make Canada’s Greenest Home as air tight as possible. In fact, we’re aiming to try and achieve a PassiveHaus approved 0.6 ac/h (air changes per hour at 50 Pa depressurization). So it was exciting today to have Matt Caruana come by and bring his blower door outfit and his laptop to give the house a first trial run! This is in advance of having Ross Elliot from HomeSol Building Solutions, our official energy rater, come by next week.

Matt Caruana calibrates the blower door and reads the results on his laptop. The blower depressurizes the house, so that outside air tries hard to find its way in. On a cold day like this one, it’s easy to feel the air coming in.

And it’s a good thing we had a first-round test with Matt!…

The first test showed that, despite all our efforts, there were some significant areas of leakage. Fortunately, they are all areas that can be addressed before the next test.

Our result for the first test was 3.15 ACH50, with an equivalent leakage area of 74 square inches (about an 8×9 inch hole in total over the 3,780 square feet of wall area, or 1/7355 of the wall area). What happened? Where were the leaks?

The good news is that we did a really good job of sealing the common areas of leakage. We detected barely any leakage from any of the windows, electrical boxes or seams between foundation and floor or between the two upper floors. All our efforts to make these areas tight definitely paid off.

There was some leakage from our temporarily taped up attic hatch and the cover over the temporary back door. These can be better taped next time around and that will definitely make a noticeable difference in the results.

By far the leakiest area was around the edges of our site-baled north wall. Despite using air fins at all the seams with the prefab walls and the ceiling, the upstairs north wall was leaking significantly all the way around where the plaster had shrunk away from the edges. A quick calculation of this 1/8″-1/4″ gap all the way around the whole north wall says that this could account for almost all the leakage area Matt detected.

This seam leaked like crazy! The air fin that extends behind the plaster was not sufficient to keep air out.

This seam used the exact same style of air fin and in this case no air came through. So our system works, but not reliably!

Surprisingly, the downstairs north wall, which is built in the same manner, using the same detailing, had barely any detectable leakage. Visually, the separation of the plaster is the same thickness, and we used the same plaster mix and plasterers, and the air fins were made in the same way. Our best guess is that the mesh over the air fin may have been better embedded in the plaster downstairs, keeping the plaster tighter to the wall. The takeaway lesson for us is that while this detail can work, it’s definitely not a guaranteed way to seal this seam.

Similarly, there were leaks along the edges of a few of the prefab straw bale wall panels. They were detailed in a similar way to the site baled walls, with an air fin under mesh around the edges of the plaster. And again, some worked very well and others did not. We’ll have to do more thinking about how to make this a more effective and reliable detail on future builds.

As with the site baled walls, a few seams in the prefab walls leaked around the air fins.

The majority of the seams in the prefab bale walls did not leak. But there was no visual indication to say which worked and which didn’t.

Fortunately, these leaky areas can be easily addressed by caulking the gaps between the edge of the plaster and the abutting wall. There is still another layer of finish plaster to go on the walls as well, which will further help to seal and protect the caulking. We’ll take care of these areas before the next blower door test, and then be able to focus in on finding the smaller holes!

A result that sees the house achieve a result somewhere between the 1.5 ACH50 of the R2000 program and the 0.6 of PassiveHaus would make us really happy!

Our results today point to the difficulties involved in making buildings as air tight as possible. We had drawn careful details at the planning stage and spent a lot of time and energy on site making sure those details were well executed, and still didn’t get a great first result. Because we’re taking the time to test at multiple stages, we will find these leaks and fix them. But not every house will get this attention to detail, without which air tightness is a nice idea but unlikely to become a reality. Each and every member of the build team needs to have air tightness in mind as they do their work, and builders need to plan for the time it takes to test and address issues. It would help if such blower door tests were mandatory!

As those who have followed the progress of Canada’s Greenest Home will know, we are taking the air tightness of this house very seriously. A great deal of thought has gone into ensuring construction details that make it easy to make an air tight enclosure, and just as much effort has gone into work on site to be sure we follow through on those details (much thanks to Graham Wise and our other diligent folders and tapers!).

Siga’s Wigluv tape makes a great seal between the window unit and the air control membrane.

As much as possible, we try to have the air tightness details addressed by building in a way that minimizes breaks in the air control layers and penetrations through these layers. However, there are places where joints and penetrations are impossible to prevent. To date, we’ve done our best to caulk and tape such areas with the best materials available to us.

That pallet of available materials just improved dramatically with our introduction to the line of tapes and membrane materials from Siga. These Swiss products are now imported into Canada by Herrmann’s Timber Frames in Curran, Ontario. As soon as we opened our first roll and began to apply it, we knew that air sealing for us was changed forever!

Siga’s Rissan tape seals the membrane to the electrical box hood.

We are working largely with two products from Siga. The first is their exterior-grade tape, called Wigluv. This tape is outrageously sticky, and the tape material very flexible. We are using the Wigluv to tape our air control layer (a conventional Canadian housewrap) to our windows to provide a seal at this important junction.

The Wigluv takes some learning to apply cleanly, as it is so sticky that any errors in application result in tape stuck to fingers and any other surface that gets in the way! However, we quickly figured out how to fold the tape against the window to provide an excellent seal. Working from bottom to top of the window, we provide positive overlap at each tape seam. The flexibility of the tape means that the odd lump or bump in the application folds down completely, and if the corner is not perfectly ninety degrees, it will bend out of the way of the strapping we put on next. I feel like these will definitely be the most air tight windows we’ve ever installed.

The second product is similar, but meant for indoor applications, and is called Rissan. This tape is flexible enough to be very useful for sealing round holes in membranes, such as plumbing vent stacks and electrical conduits. Equally sticky as the Wigluv, the Rissan bonds to pipes, wires and conduits firmly and provide a great solution to these very hard-to-seal areas of the home. We will use the tape from both sides of the barrier wherever possible to further ensure a tight seal.

Whether or not these tapes have long-term lasting adhesion remains to be seen, but their test results are impressive and they far surpass anything that is widely available in the North American market.

This entire window is now very well sealed and insulated.

For the time being, it’s too bad we have to import these tapes from Europe. Canada used to be a leader in the first wave of air tightness products for homes, but until somebody in North America starts making tapes of this quality, we’ll be using these Siga products to ensure our seams and joints are as air tight as possible.