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Building Science: What every home owner and builder should know

Building Science is a relatively new field of study, emerging over the past decade as architects, engineers and builders examined the results of the new wave of highly insulated and energy efficient buildings. Building science attempts to see a building as a whole system, rather than an amalgam of different elements. Building enclosure (roofs, walls, floors, insulation, windows, doors and barriers) and heating/cooling systems as well as occupant loads and demands are examined within building science to achieve the highest levels of comfort, efficiency and building durability and serviceability.

At Endeavour, we think it’s important that building science isn’t just left to the scientists. Homeowners and tradespeople who understand the principles of building science will make better, more informed decisions at every turn in a project. Whether it’s a minor renovation or a complete new build, the lessons of building science will make the project more energy efficient, more durable and more comfortable.

The basics of heat and moisture movement and material properties are not hard to understand, and armed with an understanding of these basics, homeowners and builders will be able to have informed discussions with designers, building officials and HVAC suppliers and installers.

Builders involved in the natural building movement of the past two decades have played an interesting role in pushing the boundaries of building science. Lessons learned in straw bale, cob and adobe buildings have helped to inform the entire building science community as the field developed into its own branch of study. To date, buildings made with natural materials have often embodied the best principles of building science (whether knowingly or not!)

You can join one of North America’s leading natural building scientists for a workshop on the Fundamentals of Building Science at Endeavour to bring yourself up to speed for your home building project or to help you become a better builder. Jacob Deva Racusin is a principal at New Frameworks Natural Building in Vermont, and a co-author of The Natural Building Companion. His four day course is open to all, and is designed to introduce and develop the concepts of building science in both a theoretical and hands-on manner. You can read the course outline here.

If you intend to achieve a high level of performance in your own home or on your professional projects, this workshop is for you!

Paperstone countertops at Canada’s Greenest Home

We spent a lot of time considering our countertop choices for Canada’s Greenest Home. It’s an area with many options, and many factors to weigh when trying to make an environmentally sound choice. Ideally, the countertop material must be durable, aesthetically pleasing, stable, renewable and/or recyclable and not off gas any chemicals into the home.

After much deliberation, we chose to go with a material called Paperstone. This type of countertop is made from 100% recycled paper fibers (complete with FSC certification), bound with a phenolic resin to create a solid, dense material that is certified food safe by NSF and resistant to high temperatures and abrasion/scratching.

One of the main attractions to Paperstone is its workability. It can be cut with typical woodworking tools, allowing us to do our own installation. We were able to shape the pieces we needed, make the sink cut-outs and bevel the edges of the material easily.

Paperstone came in a range of attractive colours, and can be finished with natural sealants and waxes.

The phenolic resin binder gave us some cause for concern. While the material does not contain any petro chemicals or off gas in the home, the resin ingredients are not environmentally benign. However, the company documents its handling practices very convincingly and has received numerous awards for its sustainability initiatives. We would like to see the company apply for Greenguard certification to ensure its claims of zero off gassing are confirmed by a trusted third party.

We obtained our Paperstone from Living Rooms in Kingston, Ontario, allowing us to work with a supplier we know and trust. This is always an important part of any product decision. The material comes in large slabs, and we bought a 5×12 foot slab from which we cut the pieces we needed.

After a lot of use (and abuse), we have been extremely pleased with the performance of the Paperstone. We gave it an initial waxing prior to use, and have not refinished it after 10 months. It is impervious to water, easy to clean, and very scratch and dent resistant. The dark charcoal colour we chose has a nice depth to it, and doesn’t show any signs of staining or wear. Areas around the sink, where many countertops begin to show signs of failure quite quickly, don’t seem vulnerable to deterioration at this point.

The countertop draws compliments from almost everybody who sees it. It looks and feels unique and attractive. While it is not inexpensive, the initial workability of the Paperstone allowed us to do the installation ourselves, saving money. And its apparent durability means that its an investment that will last a very long time. If you can afford it, we would recommend it as a good choice.


Framing systems for teachers’ union office

Wood framing is a conventional building practice that we use quite frequently at Endeavour. For the teachers’ union project, we are using wood framing for both the floor system and the exterior walls. The walls and floors may not look very different from conventional building, but from a sustainability point of view we’ve made choices that can make a large impact.

First, all the wood framing is certified by the Forest Stewardship Council (FSC), a third party certification organization that helps to ensure that wood products are harvested and processed according to high standards of sustainability. For this project, ensuring FSC certification meant going straight to a FSC certified distributor for our framing lumber and plywood as non of the local lumber yards are FSC certified.

The floor framing uses open web joists from TriForce. These open web joists do not use metal plates, but are finger-jointed and glued, using 2×3 top and bottom chords and 2×2 webs. This uses wood from smaller diameter, fast-growing trees and significantly less wood than solid floor joists, and significantly less glues than wooden I-beams with solid OSB centres. The floor joists are deep enough to allow us to achieve R-46 once they are filled with cellulose insulation.

The 2×6 wall framing is the load bearing exterior wall of the building, and will also be filled with cellulose, adding R-22 to the exterior of our bale walls (more on this hybrid system later), which will be installed to the interior side of the frame.

One of the great advantages of wood framing is the speed of construction and the low cost. When added to the renewability of wood when harvested and processed responsibility, it’s a great combination.

Earthbag foundation for floor system

In addition to the Durisol stem wall foundation, our project for the teachers’ union office includes two long sections of earthbag foundation to support the floor joist spans inside the building. The inherent insulation value of the Durisol blocks made them our first choice for the exterior of the building, but the extremely low environmental impact of earthbag foundations made them an easy choice for the interior.

Using continuous rolls of polypropylene bag material (this material would be cut and sewn to make rice, grain and feed bags) as a form for a variation of a rammed earth mix, earthbag is simple, durable and low cost.

A wide variety of material can be used in the bags, as long as it has an aggregate content capable of being tamped to a high degree of compaction. For this project, we used a road-base gravel and a small amount of a lime/metakaolin binder (you can read about this mixture here) to provide a mixture that tamps well and stays coherent after curing, even if the bag is damaged or removed. It is also possible to use aggregate and clay in the bags.

To facilitate the use of the continuous tubing, we built an earthbag loader based on a design by Kaki Hunter and Doni Kiffmeyer (authors of the excellent book, Earthbag Building), which uses a maple syrup bucket with the bottom removed and an insert made from a length of sonno-tube. The tubing is pulled onto the sonno-tube like a giant sock, with the “toe” of the sock pulled through the hole in the bucket. The pressure between the sonno-tube and the bucket prevents the tubing from continuing to pull through, unless the person loading the bags lifts the sonno-tube to allow more slack into the bag.

The material is added into the tube until the “shookler” (that’s a technical term!) determines that the desired amount of material is in the tube, and more tube is released. Behind the shookler is a tamper, who applies the tamping force that compresses the material until it has reached its limit and the proper level. We use a laser level to ensure that the top of the bag is at a consistent height.

Between each course of earthbag, a run of barbed wire is used to prevent the bags from sliding against one another. In the case of this building, we required three courses of earthbag. This was topped with a 2×8 sill plate on which the floor joists will be fastened. The sill plate is attached to the bags with long spikes as well as tie straps at regular intervals.

Though the process of doing earthbag can seem labour intensive, as a crew gets practiced it goes very quickly. Because there is no requirement for advanced formwork, it can actually be very competitive with forming and placing concrete. With a day’s practice, our crew was producing over 1.5 feet of finished bag per minute!

The beauty of earthbag is its simplicity. Bag material and fill as well as all the required tools can be found in almost any location in the world, and the strength and durability of earthbag foundations (or entire buildings) is remarkable. Bag on!

Helical pier foundation

The timber frame portion of our project for the teachers’ union rests outside the walls of the building, requiring individual foundation piers for each of the 14 posts. Typically, these would be poured concrete piers each with its own wide footing, resulting in a lot of concrete use and a lot of labour time to dig, form and pour each pier.

As an attractive option to digging and pouring concrete, we decided to use helical piers. This type of foundation is essentially a “ground screw,” consisting of a thick-walled metal tube with a screw plate on the tip. The helical piers are wound into the ground using a hydraulic device attached to a small backhoe. The screw plates are driven down to a depth below frost level and until the hydraulic force required to wind them reaches a pre-determined amount of torque. Once the proper torque has been achieved, the plates have sufficient bearing capacity to handle the loads that will be imposed on them.

Our piers were supplied and installed by Postech Peterborough. They were sized according to the engineered loads provided on our building plans. On the ground, we provided the layout points for the piers and their crew came and performed the installation.

Despite accurate points on the ground for the piers, the piers do not necessarily enter the ground perfectly straight so the tops can sometimes be off line even if the piers were started at the right point. This happened on several of our piers, so next time around, we would definitely make sure we had batter boards and string lines ready so the tops of the piers could be accurately aligned.

The piers are left long, and we cut them to height after the installation. A wide range of pier caps can be used depending on the type of post or beam being attached. Most of the caps use a threaded rod to allow for fine adjustment of the pier height.

One of the advantages of helical piers is there is no digging required, meaning that the site is barely disturbed. The installation of our 14 piers took about 5 hours, making it a quick process. The piers are ready for use immediately upon completion. The galvanized steel used for the piers is a high embodied energy material, but relatively little material is needed compared to concrete or other alternatives.

A Durisol stem wall foundation

Over the past few years, we have turned to Durisol insulated concrete forms (ICFs) several times. They offer an attractive blend of sustainable features with the convenience of conventional methodology.

For the teachers’ union office project, we needed a short stem wall to raise the walls of the building a suitable height above grade. There is no basement, and the footing is a shallow, frost protected perimeter beam, so the stem wall is only 2 feet tall. Durisol blocks provided us with a solution that worked well for several reasons. The blocks have a high insulation value (R-21 to R-28), are made from a very high percentage of recycled content, and are produced within a reasonable distance of our building site. They form a 5.5-inch concrete wall, using much less concrete than a full foundation wall (typically 8-12 inches wide).


In addition, the blocks come in several widths which for this building meant that we could use the 14-inch wide blocks as the first course and 12-inch wide blocks on the second course, leaving us with a 2-inch lip on which we could rest our floor joists. By keeping the floor joists within the insulated walls, we minimize thermal bridging and simplify air tightness at this important seam.

The Durisol blocks are dry stacked on the footing and on each course, making them very fast to install. They can be cut with a regular circular saw when necessary, and take a wood screw very securely. For our curved foundation, we did not attempt to cut the blocks to match the curve. Rather, we set them so the inside edges were touching on the curve and used a site-mixed hempcrete to fill in the gaps.

A lime-cement plaster is used to coat the exterior of the blocks, and we used a water-based, no-VOC liquid rubber and a 100% recycled content plastic dimple mat to complete the waterproofing layers on the exterior.

While this foundation wall still has relatively high embodied energy (due to its cement content), its energy efficiency, the lack of foam products, durability and the ease of construction make it an excellent option.

A unique shallow frost-protected foundation (SFPF)

In the pursuit of foundations that use little or no concrete, we have two common strategies that we often use. The first is rubble trench foundations (you can see an example here), and the second is shallow frost protected foundations (SFPF). Our extremely flat and low lying site this year dictated the use of a shallow foundation to avoid potential drainage issues in a deep trench.

The teachers’ union office building has two extensive curved sections in the foundation, and this would have made a conventional footing formed with 2×8 lumber difficult to achieve. A great new product called Fastfoot allowed us to make this footing very quickly and easily, and is a product we’d definitely use again. Made from a woven polypropylene, the Fastfoot uses lightweight stakes in the ground and small dimension lumber fastened to the stakes to support a fabric formwork (in many ways similar to doing earthbag footings) into which concrete is poured.

The Fastfoot system has several advantages over conventional formwork. We were able to use lightweight stakes and 2x4s (or doubled 1x4s to achieve the curves), despite the footing being 8 inches deep, rather than needing 2×8 lumber. As the formwork is draped by the Fastfoot fabric, the footing lumber does not get covered in concrete. This means when the forms are disassembled we can reuse the lumber without having to clean it. The fabric of the Fastfoot system is also a barrier to rising dampness from the soil beneath, adding a layer of protection from underneath. We were able to wrap the “tails” of the fabric up and over the footing and tie it into the foundation wall moisture proofing layers, adding a positive lap to the intersection between footing and stem wall.

The lines stamped onto the Fastfoot fabric make it easy to line up within the forms, and allow for many different widths of footing. There is no waste with the system, as the fabric stays in place. Joints in the fabric are overlapped by about a foot, and a folding pattern allows for corners to be handled easily. Our curves required us to make folds at regular intervals, and this too was easily done.

We had a few small issues when we poured the concrete into the form and had the fabric slide to one side under the force of the concrete. This pushed the fabric out on one side and left a concave section on the other. In these areas we had to shovel the concrete a bit to get the form centred again. We wouldn’t make that mistake again as it’s easily avoided.

Fastfoot is an excellent addition to our sustainable building toolbox.

2014 Workshop Schedule

Our 2014 workshop schedule is now posted!

We’ve got some great fall workshops! Fundamentals of Building Science, Hempcrete, Straw bale building, plastering and more…

Off-grid job site power system

Many sustainable building projects are built in places where it is difficult or impossible to access electrical grid power, and this necessitates running a gasoline or diesel powered generator to provide power for tools. Over the course of an entire building project this can add up to a lot of fossil fuel… I have records from one job that show we used 2,250 liters of gas over a five month period! Hard to be making claims about sustainable building when that much fossil fuel is being burned in the process.

Despite our project for the teachers’ union being in a very urban location, there was no accessible grid power and we did not want to run a generator again. The cost of running a temporary electrical service (including utility fees and electrician’s time) was around $2500, and then there would be charges for the power used on top of that.

We spoke with Sean Flanagan of Flanagan and Sun about a PV (photovoltaic) based system that could run our job site, and the price tag was about $3800. More than the temporary power, but once built the system could be used again and again in the future. Our clients at the Trillium Lakelands Elementary Teachers’ Union generously agreed to put the budgeted cost of temporary power toward the system, clearing the way for the Sustainable New Construction class of 2014 to be powered by renewable energy!

The system features 480 watts of photovoltaic output, and is coupled with two large deep cycle batteries and a 3,000 watt sine wave inverter to provide power to the tools. A MPPT (maximum power point tracking) charge controller is the “brains” of the system, matching the amount of charge from the panels to the needs of the batteries.

After trouble shooting through some issues with the first charge controller (wrong unit for the PV voltage), our site now runs on 100% renewable energy, without the noise and pollution and cost of running a generator. We do face some limitations… if multiple tools try to start up at exactly the same moment the breaker on the inverter will trip. On a cloudy day with the air compressor running almost constantly, we can have difficulty running other tools. But living within limited means is all part of sustainable building and living, and it’s a good lesson to be reminded of during construction.

The silence and the clean air are well worth the small sacrifices. We’d encourage other builders to consider similar systems. The system is small enough to fit in a typical tool trailer, and we’ve also known builders to carry the batteries and inverter in their trucks, using the truck’s alternator to also charge the batteries as they drive to and from the job site. If each project can eliminate the need for hundreds of liters of fossil fuel, that would be a worthwhile impact!

Finding LED lightbulbs that work

Since my first days of living off grid with a tiny PV system in the late 1990s, I have been somewhat obsessed with finding lighting that combines low electrical draw with a nice quality of light. In the off grid home, we moved from dim, incandescent 12-volt car lights to brighter 12-volt halogens to the first generation of 12-volt compact fluorescents (CFLs). None of these combined low electrical consumption with a good light quality. The addition of an inverter in that home opened up the potential for newer generation CFL bulbs, which over time developed a better quality of light, but never really satisfied me. The inclusion of mercury in the CFLs always made me uncomfortable, as did the flickering quality of the light.

LED lighting that works

The LED bulbs that really work!

When the first LED bulbs started to become available a decade ago, I was all over them. I bought bulbs at outrageous prices that gave ridiculously poor light, and have continued to buy examples of each new generation of LED bulb for the past ten years.

Having decided to outfit Canada’s Greenest Home with LED lighting in every fixture, I have taken the opportunity to buy just about every brand and type of LED bulb that are available through major retailers. It is exciting to find that there are, finally, LED bulbs that combine low wattage with excellent light quality!

The sampling we’ve done has been for general purpose overhead fixtures and lamps, and also spots for over the cooktop.

Here are the ones we really like:

Philips 11 watt, 830 lumen, 2700K, dimmable

This bulb has a nice warm light. The shape of the bulb seems like it would cast a fairly narrow spot of light, but it actually does a good job of spreading light in 360 degrees. We use this one as overhead lights in the kitchen and in a couple of the hallways. A really good general bulb.

Cree 9.5 watt, 800 lumen, 2700K

This round bulb has the best general light distribution of those we tried, with a shape most resembling the traditional incandescent bulb. The light is definitely at the warm end of the spectrum, but slightly less warm than the Philips. This is also a really good general use bulb. The glass is coated in a rubbery material that makes it easy to handle and twist the bulb, and should protect it well against breakage.

Sylvania 8 watt, 470 lumen, no spectrum data on bulb or package, dimmable

This bulb is less bright than most of the others, with a lumen output of only 470. We found it to be a very warm and pleasant light. We currently have some exposed bulbs in the house, awaiting actual fixtures, and this bulb casts a good, wide light without being too bright and glaring. The light from this bulb feels “calmer” than any other, good for background lighting.

Philips 10.5 watt, 800 lumen, 3000K

If you’re under the impression that LED bulbs can’t cast a good, bright light, this bulb will alter that perception. It is surprisingly bright, with a light that is close to daylight spectrum without feeling “cold”. In any fixture where you desire an intense, 360-degree light, this one is perfect. It also the least expensive bulb, with prices under $10 at several retailers.

Feit 2 watt, 160 lumen, no spectrum data on bulb or package

We put these bulbs in a few sconce fixtures in stairways and hallways where we wanted a low but useful amount of light in a neutral spectrum range. These little bulbs work very well in this scenario, drawing only a small amount of current while producing a surprising amount of light.

Philips 7 watt, 280 lumen, 2700K spot

We haven’t sampled as many spots as regular bulbs, but of those we’ve tried this one combines a good quantity and quality of light and does not have as narrow a focus as many of the other brands. A pair of them shine down on the stove from the hood vent.

This is far from a scientific and complete sampling of LED bulbs, and I’ll continue to be a bulb addict and buy new models as they come out. However, this range and selection of models would allow anybody to outfit a home with LEDs and feel confident that their money is being spent on quality bulbs with good light output. Prices for these bulbs range from $9-15 dollars. In Ontario right now, there are government rebates of $5 on a wide range of LED bulbs, including most of those listed here. It’s a great time to invest in energy saving bulbs that are long-lasting and do not contain mercury!