NOTES FROM THE UNDERGROUND
DECEMBER 6, 2010My last two columns have been about the timbers and posts that hold up our roof. As our construction progresses, we can now talk about that living, green roof.
A green roof is one of the primary reasons to build an earth-sheltered house because this kind of roof is an insulator from winter’s cold and summer’s heat. The rest of the time it can be a garden, a patio or a soccer field.
Unfortunately, a green roof isn’t just a case of piling dirt on your shingles. There are many considerations, including insulation, waterproofing, drainage, soil depth, slope and enough moisture retention to support the plants you want to grow. A green roof is a many-layered thing.
First, we needed an interior ceiling above the beams. We didn’t want a standard drywall and paint ceiling and were lucky enough to source the 4.5-cm (1 3/4-inch) pine tongue and grove decking that was the original floor and ceiling of the Ottawa airplane hangar that also provided our beams. Not only would this give us a wooden interior ceiling, but the beams would be reunited with their long-time companion, the decking.
Each plank had to be sanded and, in some cases, planed, but we decided to spend money on local labour rather than materials that have been shipped a long distance. It is turning out that working with young, local labour (most of the very accomplished crew is under 30 years of age) has been a highly rewarding part of this project.
Next, we needed a strong, flat surface on top of our interior decking to form the base of the exterior roof. We considered many materials, including concrete, but finally settled on structurally integrated panels (SIPs) that are non-CFC polyurethane foam sandwiched between sheet steel. Ours were four feet wide, and varied from eight to 20 feet in length.
The rigid insulation core of the SIP performs as insulation, vapour barrier and air barrier. A well-built home using SIPs will have a tighter building envelope and higher insulating properties to reduce drafts and operating costs. Our six-inch thick SIPs were rated as R-45. Also, due to the standardized and all-in-one nature of SIPs, construction time can be reduced over building a frame home and requires fewer trades for system integration. The panels can be used as floor, wall or roof.
Once we decided on SIPs, the next stage was finding them. There are SIP distributors in major centres, just like other building supplies, but we found a Toronto supplier who had panels with cosmetic defects that were originally for the walls of big-box stores. We were able to buy enough in various colours for the house for $7,500, about half price and a significant savings.
The beauty of SIPs is that they provide a smooth, flat surface for the impermeable membrane that seals the roof from the soil on top of it. As you can imagine, the main villain in earth-sheltered construction is moisture, so a membrane that keeps moisture out is essential. Again, we researched many different materials but decided to go with proven, tested material used in flat roof applications called EPDM (ethylene propylene diene monomer synthetic rubber). It is also used for water resistance in high-voltage cable, as a pond liner, in RV roofs and chainmail applications. I guess modern knights want to be resistant to moisture, as well as battle-axes.
The main properties of EPDM are its outstanding heat, ozone and weather resistance. We had an EPDM roof on our underground generator house at the farm that was also a patio of sorts on the ground above. It was exposed to the sun and the elements for ten years and, other than a bad corner where I chewed it with the lawn mower, it looks the same as the day we put it on.
EPDM does not pollute runoff rainwater, which is of vital importance to us because we will collect this water in a rain barrel and use it to water plants. Many houses equipped with rainwater harvesting use EPDM roofing.
A second option would have been to spray a rubber coating on the roof. It sounds intriguing because it eliminates worry about sealing any seams, but we didn’t find out about this method until after our roof was completed. I was giving my Queen’s sustainability class a tour, and one of the students mentioned spray-on rubber roofing, but by then it was too late. We installed a bed of half-inch cellulose roofboard on top of the SIPs to eliminate any possibility of punctures, then we were ready for the membrane.
The 60-gauge (1.50-mm thick) rolls of EPDM that we used weighed more than a ton, so they had to be lifted to the roof by crane. It took a day to lay out the membrane and seal the middle seam, then reinforce the corners. Once the glue was dry, we dammed the edges and flooded the entire surface with 13,000 litres of water weighing 13 metric tonnes from the garden hose — a good test of the roof for both moisture and strength.
It passed, so we proceeded to the several green roof layers above the membrane, and I’ll give you the dirt on that next time.
NOVEMBER 4, 2009
RECLAIMING OUR HERITAGE, PART 2
As I mentioned last month, we have made a commitment to using reclaimed building materials as much as possible, and the centrepiece of this strategy is reclaimed Douglas fir beams originally milled in British Columbia. Although now fairly unique, Douglas fir was the structural steel of a century ago when millions of board feet of fir were harvested and milled.
In the 1880s, the construction of the Canadian Pacific Railway created a greater demand for B.C. lumber. With the railway’s completion in late 1885, lumber exports to eastern Canada and the world increased as railways were extended right into the logging camps. By 1912, there were 365 kilometres of logging track on the British Columbia coast.
Around 1897, the steam-powered donkey engine, introduced from the U.S., replaced oxen. The steam donkeys increased the speed of work and volume of timber that could be logged, but they also increased the danger to the workers. Another innovation was the “high lead system,” in which a line high over the skids pulled or lifted the logs over obstacles.
Today, the mill buildings themselves provide a primary source of reclaimed wood. Some of these buildings and complexes housed more than a million square feet of floor space and can yield three to five times that amount of board feet of flooring. One of the most famous is the Long-Bell Mill south of B.C. in Washington state.
In 1918, lumber baron Robert A. Long’s southern U.S. timber holdings were nearly depleted. He and a small crew went on a horseback exploration of the virgin forests in the Cascade Mountains in southwestern Washington, where it is estimated that the trees averaged nine feet in diameter and 150 feet in height. It must have been breathtaking, even for a man who had spent a lifetime logging ancient forests.
The Long-Bell Lumber Company purchased 70,000 acres that held about 3.8 billion board feet of lumber. Construction of the 72-acre mill complex and the town that would support 14,000 mill workers began in 1922. The mill reached full capacity in 1926, milling two million board feet of lumber a day.
The mill fell silent in 1956 because of the move to cheaper, less permanent construction, but left itself as a legacy: 30 mill buildings that averaged 700 feet in length, constructed with large, old-growth timbers of clear, straight-grained fir.
When it was decided to dismantle the buildings, word quickly spread among timber framers, but Bill Gates bought seven million board feet, quickly pricing the timbers beyond their reach. But even Gates couldn’t use it all, and over the next few years five million board feet became available to timber framers across the continent, further fueling the timber frame revival.
While our timbers are among the biggest I’ve ever seen, they are babies compared to what was harvested and milled from the west coast of North America. The Long-Bell Mill produced the incredible lumber cants in the photo below in the early 1900s, but it was the salvaged timbers from the dismantled mill itself that contributed to many modern timber frame homes.
Photo courtesy Longview Public Library, Longview Room Collection.
We sourced our beams privately so I cannot recommend any reclaimed lumber dealers. However, below are some places to start if you are looking for reclaimed lumber.
•Century Wood Products Offers reclaimed wood building supplies and provides custom cutting and milling services.
•Logs End Inc. Recovers and mills heritage Canadian old-growth wood to produce dimensional lumber, flooring, paneling, beams and more.
•Nostalgic Wood, Inc. Produces kiln dried custom milled flooring, trim and doors from reclaimed lumber.
•Timeless Material Company Offers salvaged lumber and timber, flooring, antiques and more.
•West Lincoln Barnboard & Beams Ltd. Offers aged antique wood flooring, panelling, and door and window trim recycled from old barn woods by barn salvage specialists.
Reclaimed wood is not only beautiful, it's environmentally conscious as well. It is estimated that over three trillion board feet of lumber have been produced since the early 1900s, and much of that lumber is still in old buildings.
I like the idea of living under ceiling beams that are at least 300 years old. Finding and reclaiming some of that old lumber will give your building project a unique appearance as well as demonstrate a commitment to reusing our resources. After all, sustainability means meeting the needs of the present without compromising the ability of future generations to meet their own needs.
OCTOBER 1, 2009
RECLAIMING OUR HERITAGE
The phrase reduce, reuse, recycle is purposely listed in order of sustainability. It is always better to reduce our consumption, then reuse products, and only then to recycle as much as we can.
In our new house so far, we have made a commitment to reducing our floor space to under 2,000 square feet and to using reclaimed building materials as much as possible. Lumber is a renewable resource but, despite the best precautions, logging is a destructive industry. Much of the mass of a tree is burned or buried or left on the forest floor just to harvest the trunk. Landscapes are inevitably destroyed and sequestered carbon is released in the logging process. There is always waste in milling, and many levels of transportation are required from forest to mill to distributor to consumer.
It may make environmental sense to incur only reclamation and short-haul transportation costs by using reclaimed lumber instead. Another riff on the theme of “buy local,” as long as we don’t try to dismantle our neighbour’s shed when they are away on holiday.
Most reclaimed lumber comes from timbers and decking rescued from old barns, factories and warehouses, and some companies have been known to source wood from less traditional structures such as boxcars, coal mines and wine barrels. Reclaimed or antique lumber is used primarily for decoration and home building and is often used for siding, architectural details, cabinetry, furniture and flooring.
So far, we have been able to use reclaimed lumber as fir structural beams and inch-thick pine tongue and groove ceilings. We will also use reclaimed cedar barn board for siding.
Reclaimed lumber is popular for many non-environmental reasons: the wood has a unique, aged appearance, the history of the wood’s origins can be interesting and the wood’s physical characteristics include strength, stability and durability. Survival in an old-growth forest can be difficult. A tree grown on a tree farm doesn’t have to compete for space and light, and it will be harvested before it gets very old, so its growth rings will be widely spaced. But a tree that grew in an ancient forest had to compete with other trees, so it grew more slowly. That's why old-growth timber is strong and its rings are dense.
Many of the largest fir beams in Canada, like the ones in our house, came from British Columbia. In 1865, Hastings Sawmill opened on Burrard Inlet in Vancouver and was given timber rights to much of the surrounding area. Soon there was a mill in North Vancouver.
In 1868, Gassy Jack Deighton opened a saloon nearby. (OK, I know his credibility as a cook is immediately shot but, in those days, “gassy” meant someone who talked a lot.) This was the beginning of Gastown, the small village that would grow to become Vancouver.
Logging was mostly done by hand. Horses or oxen dragged felled trees along corduroy roads, trails with small logs placed across them. The logs were greased to reduce friction and the ridges made by the logs resembled corduroy fabric. These were called “skid roads” and they led to the water where the huge timbers were floated to the mills.
In B.C., loggers put a springboard into the tree above the ground. Two axe men stood on the board and chopped at the tree with heavy, double-edged axes. They also used long saws with handles at each end. You can see the loggers standing on their springboards in the photo below.
When the last of these majestic giants were felled and the big timber taken to the sawmills, it was the end of a special era in our country’s history. The conditions that allowed them to grow slowly and develop their dense heart centres would never be present again. Old growth by its very nature, taking hundreds of years to mature, was not considered for replanting and is now replaced by faster growing varieties.
Reclaimed beams can be sawn into wider planks than the harvested lumber. These old used wood beams come in sizes that are unmatched in today’s lumber yards and are much less likely to twist, warp or shrink because they have been exposed to many changes in humidity over a long period of time. In some cases, the timbers from which the boards were cut have been slightly expanding and contracting for over a century in their previous installation.
Barns serve as one of the most common sources for reclaimed wood in Ontario, and most farm buildings constructed up through the early part of the 19th century were typically built using whatever trees were right there on the property. They often contain a mixed local blend of oak, maple, pine, cedar, poplar and sometimes hemlock. The wood was either hand hewn using an axe or squared with an adze, and has a lovely character.
Next month, I’ll provide more information on the B.C. and U.S. west coast milling operations, including the famous Long-Bell Mill, and include a list of where reclaimed lumber is available in our area.
SEPTEMBER 1, 2009
ON THE BEAM
Our drainage and foundation are in, the floor is poured, and the ICF walls are filled with concrete. Now we can turn our attention to the earth-sheltered roof. Because most of our house is covered with earth three feet thick, something strong has to support the roof.
Of course the placement of the beams was crucial to the whole project, and our engineer did the required calculations and drew up this timber diagram for us.
The first requirement is an accurate calculation of the weight of the soil — not as easy as it sounds because soil weight depends on many variables such as the type of soil (clay has smaller particles and is therefore heavier per volume than sand) and, of course, the moisture content.
Slightly moist topsoil typically weighs 650 kg per cubic metre, so we have about 60 metric tons of weight spread out over the whole roof on a dry day (and that weight could be multiplied two or three times after a rain), which is much more than I would like to fall on me. So we needed something strong to hold up the roof.
That something is beams of Douglas fir from British Columbia that are nearly a century old, since fir was the structural steel of the first half of the 20th century.
Douglas fir is not a true fir, and has been a taxonomic nightmare for those trying to settle on a genus name. After changing names on numerous occasions, the present scientific name Pseudotsuga menziesii now uniquely belongs to Douglas fir, and the common name honours David Douglas, the Scottish botanist who first introduced it into cultivation at Scone Palace in 1827. To make things even more complicated, two different varieties of the species are recognized. There is coast Douglas fir and blue Douglas fir.
When architects and engineers look for the best in structural timber, their first choice is often Douglas fir. It is universally recognized for its superior strength-to-weight ratio, its excellent nail-holding and fastening capability, and its superior performance record against wind, storms and earthquakes.
In strength properties, Douglas fir has the highest ratings of any western softwood for extreme fibre stress in bending; tension parallel-to-grain; horizontal sheer; compression perpendicular-to-grain and compression parallel-to-grain.
It also has the highest modulus of elasticity (E) values of all North American softwood species. E is the ratio of the amount a piece of timber will deflect in proportion to an applied load. This reflection of stiffness is one of the most important considerations in the design of floors and other horizontal systems. Douglas fir is often selected for four- and five-storey timber frame buildings.
Because of its physical working properties and dimensional stability, many builders worldwide prefer Douglas fir for framing timbers. The final plus for us was to use beams reclaimed from the first airplane hangers built in Ottawa, at what was then called Hunt Club airfield in the 1920s.
At 46 cm high, 15 cm thick and 5.5 metres long, the beams each weighed about 2,500 kg, so they were loaded and unloaded with a backhoe.
The external ICF walls filled with concrete made an excellent support for our beams, so we formed beam pockets to receive them by making boxes slightly larger than the ends of the beams and placing them in the empty walls before pouring the concrete.
After the pour, the boxes were removed, which left pockets to receive the beams.
One of those pockets was commandeered by a mother robin who built a nest, laid her eggs, and raised a clutch of chicks before she moved on and we removed her nest to put in the beams.
Four of the beams were doubled, which were perfect for the Great Room with the curved northern end that is shown on the left-hand side of the framing diagram. These beams had to support the second-storey office where our desks in the curved end will look upriver at the rapids. You can get a sense of the massive size of these beams below as Susan stands at the construction bar waiting for her drink.
Of course, the beams had to be planed, slightly sanded and cut to fit the dimensions of the house. This was work for a crew of two for about a week; then the framing began with the beams lowered into place with a crane. Each one was uniquely fitted to its beam pockets and the panoramic photo below shows the beams in place. Before you send in comments, though, note that the actual ceiling is level, not as shown by the wide-angle lens.
Next time, I will provide more detail about the beams, corbels and the decking above the beams that form the interior ceiling.
AUGUST 1, 2009
BUILDING FOR WALL-E (WALL EXCELLENCE)
There are many materials for building walls: stone, wattle and daub, and the Three Pigs Construction Company’s recommended straw, sticks or brick, depending on your budget. But more than just money is at stake. The material used to build your home’s walls is of crucial importance in sustainability because our buildings have a tremendous environmental impact. According to the Green Building Council, they account for:
•71 per cent of our total electricity consumed.
•39 per cent of total energy consumed.
•39 per cent of total CO2 emissions produced.
•30 per cent of total raw materials consumed.
•30 per cent of total waste produced.
So, when deciding on wall materials, those that reduce energy use with a minimum amount of waste are probably better. Certainly, if you want Leadership in Energy and Environmental Design certification (LEED), there are few materials that qualify and, if you are building for strength and water resistance like we are, the list gets even shorter.
One material on that short list is Insulating Concrete Forms (ICF), formwork for concrete that stays in place as permanent building insulation for energy-efficient, cast-in-place, reinforced concrete walls, floors and roofs.
The forms are interlocking modular units, Lego for adults, that are dry-stacked without mortar and with reinforcing steel (rebar) added before concrete placement to give the resulting walls flexural strength, similar to bridges and highrise buildings made of concrete.
Once stacked, concrete containing pea gravel for increased viscosity is pumped into the cavity to form the walls. Usually, the forms are filled with concrete in one- to four-foot sections to reduce the risk of blowouts like with other concrete formwork although, as you will see later, that didn’t completely prevent them in our case.
After the concrete has cured, the forms are left in place permanently to provide:
•thermal and acoustic insulation.
•space to run electrical conduit and plumbing. The foam on either side of the forms can easily be channelled to accommodate electrical and plumbing installations.
•backing for gypsum boards on the interior, and stucco, brick or other siding on the exterior. Most forms have vertical furring strips built into the forms on six-inch, eight-inch or 12-inch centres that are used to secure interior and exterior finishes.
ICF can be made from a variety of materials, but we used the most common — expanded polystyrene (EPS). Polystyrene can be transparent or can be made to take on various colours. You know expanded ICF polystyrene as foam coffee cups, packing peanuts and insulation.
This is what our assembled and braced ICF walls looked like, ready to be filled with concrete.
This is what our assembled and braced ICF walls looked like, ready to be filled with concrete.
There are many advantages to ICF:
•Minimal, if any, air leaks, for improved comfort and less heat loss compared with walls without an air barrier
•Thermal resistance typically above R-24, saving energy
•High sound absorption compared with framed walls
•Structural integrity. ICF creates a monolithic concrete wall that is 10 times stronger than wood-framed structures, especially important when part of your house is underground, as ours is.
•Higher resale value due to longevity of materials
•More insect resistant than wood-frame construction. When the building is constructed on a concrete slab, as ours is, the walls and floors form one continuous surface, keeping out insects.
•Concrete does not rot when it gets wet.
•Reduces HVAC operating costs from 30 per cent to 70 per cent
•Designing and building with ICF helps attain LEED Green Building status.
•Possible "greenbate" from the manufacturer of $1 for every full height block used in the construction of single-family homes that receive LEED certification
However, there are always disadvantages:
•Adding or moving doors, windows or utilities is harder once the building is complete because it requires concrete cutting tools.
•An average ICF home will cost about $5 per square foot more than a conventional wood-framed home, although for high-end homes constructed of concrete, ICF is usually less expensive.
•During the first weeks immediately after construction, minor problems with interior humidity may be evident as the concrete cures, so it is important not to close the house in too quickly. Alternatives are using a small residential dehumidifier or the building’s air conditioning system.
•Polystyrene is classified (according to DIN4102) as a B3 product, meaning highly flammable or easily ignited. This is one grade higher than wood, classified as B2 or normal combustibility. Consequently, polystyrene is prohibited in any exposed installations in building construction. It must be concealed behind drywall, sheet metal or concrete.
There were three disappointments for us in using ICF. The first is that EPS doesn’t grow on trees; that is, it is not a renewable resource. The second was that we couldn’t find a local source of more environmentally friendly concrete. The third was that we had to take two pickup truckloads of waste to the landfill. That is a small fraction of the waste in building a normal home, but it still needn’t have happened.
The problem is that we couldn't find anyone in Belleville, Napanee or Tamworth who would recycle our ICF. EPS can normally be recycled and has the number "6" as its recycling symbol, but our ICF was not stamped and was, therefore, not eligible for recycling.
Unrecycled EPS, which does not degrade very quickly, is often abundant in the environment, particularly along shores and waterways, and is a form of pollution.
Expanded polystyrene scrap can be easily added to products such as EPS insulation sheets and other EPS materials for construction applications, and manufacturers commonly can’t get enough scrap.
Recycled EPS is also used in many metal casting operations. It can be combined with cement to be used as an insulating amendment in the making of concrete foundations. Although EPS recycling is not a closed loop, producing more polystyrene, polystyrene cups and other packaging materials can be used as fillers in other plastics.
Once we had the walls assembled and braced, we were ready to fill them with concrete. This went very well with a pumper truck and boom so we could direct the concrete wherever we wanted. In addition, we used an eight-foot vibrator rod to help settle the concrete to the bottom.
We did have one blowout, though, and quick action by the crew plus some concrete shovelling afterward prevented a disaster.
In general, ICF structures are much more comfortable, quiet and energy-efficient than those built from traditional construction materials. It was clearly the best choice for us, especially since most of our house is underground. It may be the best choice for you, too.
JULY 1, 2009
DRAIN FOR RAIN
In the last post, I detailed our experience pouring our concrete slab. This time, I’d like to invite you into my time machine to go back to what that slab was poured on. I’m afraid I messed up the chronology there, and these time machines are real energy pigs and I try not to use them too often. I promise to do better in our shared future.
When we first researched the site in August 2008, we found a lovely wooded south-facing slope, populated here and there with mossy boulders. Seemed like a good place to find a leprechaun. A large oak tree dominated, with cedars, ash, basswood and one lone white pine gathered around like courtiers. The topsoil was a sandy loam, perfect for good drainage.
And good drainage is the first requirement for an earth-sheltered house, as you can imagine. If you get the drainage wrong, you end up living in a damp basement — only good if you are a member of the mushroom family. Moisture was the number one problem mentioned by the owners of the earth-sheltered houses that we visited, so we were very aware of our drainage. And, every indication was sand, so we didn’t bother to dig a test hole.
In October 2008, we started the first step of clearing the minimum of trees and the second step of digging into our perfect sandy soil. This is the hardest part, seeing a woods turned into a construction site. Luckily, it only lasts until the house is built.
A metre down we hit disaster — clay. Getting water to drain through clay is like swimming in molasses. The water just stays there, and the clay becomes a gooey, sticky muckhole. Definitely not where you want to live.
Soil is mostly composed of finely ground rock particles, grouped according to size as sand, silt and clay. Each particle size plays a significantly different role.
The largest particles, sand, determine aeration and drainage characteristics. The study of individual grains can even reveal historical information about their origin and history of transport. Quartz sand that is recently weathered from granite or gneiss quartz crystals is angular. Called sharp sand in the building trade, it is preferred for concrete and in gardening where it is used as a soil amendment to loosen clay soils. In contrast, sand that is transported long distances by water or wind will be rounded with characteristic abrasion patterns on the grains’ surface. Desert sand is typically rounded.
The tiniest soil particles, submicroscopic clay, chemically bind with water and plant nutrients to create a plastic texture. This accounts for the sticky goo in the spring and that bulletproof slab in the summer. Clay is typically formed over long periods of time by the gradual chemical weathering of rocks by low concentrations of carbonic acid and other diluted solvents. In addition to the weathering process, some clay minerals are formed by hydrothermal activity.
Clay may be formed in place, but thick deposits are usually found as sediment after they have been eroded and transported from their original location. Although we think of beaches as sandy, clay is typically associated with large lake and marine deposits.
The ratio of the sizes determines soil type: clay, loam, clay-loam, silt-loam and so on. Well, a metre down on our site, it was pretty much clay-clay.
Now, clay has many uses. You can write on it, build with it, smoke through it and cook in it. You can use it to bulk up cattle feed and treat an upset stomach. But we weren’t too happy to find it and, unless we wanted our own version of pottery barn, we had to do something about it.
A normal slab may have about 45 cm of crushed stone with 10-cm drains running through, installed inside the footings; then the slab is poured on top of that.
We didn’t want to take any chances. For our third step, we put down a layer of bubble-style insulating blanket (R 2) over the entire footprint of the house. Fourth was a 45-cm layer of crushed stone with 15-cm drains running through it. The insulating blanket kept moisture from soaking the stone from underneath and prevented the stone from being pushed unevenly into the clay.
Fifth, we built the forms for the footings on this layer.
Sixth, we added another 45 cm layer of stone with 10-cm drains inside the footings before we poured them as the seventh step. “Double drains for heavy rains” was our motto. Also, more than double cost, thanks to clay, but we wanted to be absolutely watertight. That’s one of the drawbacks of an earth-sheltered house; it is very site-specific. If you don’t have just the right site, you have to make one.
Eighth, the rough-in plumbing was installed. Ninth, we laid down 7.5-cm sheets of high-density expanded polystyrene foam (EPS, R-12). Tenth, a vapour barrier of six-ml polyethylene was carefully taped and sealed. The 11th step was to cover everything with wire mesh; then the heating contractor came and wired the in-floor heating lines to the mesh for the 12th step.
Thirteenth, the concrete was poured around and over the heating lines to make the final floor. Then, 14th, additional sheets of high-density EPS were laid in place for two metres out from the perimeter of the footings to prevent frost from moving horizontally underneath. Fifteenth, these sheets were covered with screening to prevent rock punctures. A final 16th step will be to replace the topsoil.
Sixteen steps for insulation and drainage so we won’t have feet of clay.
By the way, this phrase “feet of clay” comes from the Old Testament (Dan.2:31-32). There, the Hebrew captain Daniel interprets a dream for Nebuchadnezzar, founder of the new Babylonian Empire. Nebuchadnezzar had dreamed of a giant idol with golden head, silver arms and chest, brass thighs and body, and iron legs. Only the feet of this image, compounded of iron and potter's clay, weren't made wholly of metal. Daniel told Nebuchadnezzar that the clay feet of the figure made it vulnerable, that it prophesized the breaking apart of his empire. Over the years, readers of the Bible were struck with the phrase “feet of clay” in the story and it was used centuries ago to describe an unexpected flaw or vulnerable point in the character of a hero or any admired person. (Encyclopedia of Word and Phrase Origins by Robert Hendrickson, Facts on File, New York, 1997.)
If you are on clay, you may have a sump pump to remove excess water. Although these pumps are small, they can be big users of energy, especially in the spring. During power interruptions, the pump doesn’t run and that could mean a water disaster. Unfortunately, a battery or generator backup just for a sump pump moves you even further from sustainability.
We do not need a pump because our drainage is now in place. Most new houses come with sump pumps as standard equipment, which allows the builder to ignore site selection and cheat on the drainage. A house that requires a sump pump is either built in the wrong place or built badly, and it should be a red flag when buying that house. It’s another case of relying on energy-eating machines to do our thinking for us.
We are making a garden, also in clay, so I will soon post some tips about gardening in clay.
JUNE 8, 2009
BEING CONCRETE
Concrete begins as careless, slovenly and entirely feckless. It is promiscuous and easygoing, willing to flow this way and that, open to being shaped, doing what anyone wants if that person is strong enough to hold it.
Once it is committed, though, concrete becomes fanatically adamant.
I don’t know about you, but I constantly find that the world is more complicated than I thought. Take concrete. It isn’t just hard, heavy stuff. Once I started looking into it, I found hundreds of different kinds, applications, chemical reactions — it just goes on and on.
We were going to pour a multi-arched concrete roof to cap our home before covering it with earth, but the engineering specs and our bank account convinced us to go with timber framing — which, as it turns out, is a more esthetically pleasing alternative, too. Still, we needed concrete for footings and the main slab floors.
First, we had to make sure our slab wouldn’t get wet feet. We thought our site was mostly sand, but we hit the dreaded clay after excavating just a few feet. That meant we had to take special precautions about drainage because an earth-sheltered home’s nemesis is moisture. So we put down 30 cm of clean stone and installed 15-cm drains before pouring the footings. Then, around the footings, we added the normal 20 cm of clean stone and 10-cm drains. We put down five cm of rigid foam insulation next, then wire-reinforcing mesh, then installed the radiant floor heating lines. Finally, we were ready to pour our 12-cm concrete slab. In the photo below, you can see the completed parlour and kitchen slab with the rest yet to go.
Concrete is composed of cement (commonly limestone with small quantities of other materials, such as clay, heated to 1450C in a kiln) as well as other materials such as fly ash and slag cement, aggregate (generally gravel, limestone, or granite plus a fine aggregate such as sand), water and chemicals.
Concrete may have been used to build the Great Pyramids about 5,000 years ago. The perfection of the technology was left to the Roman Empire, and the widespread use of concrete in Roman structures has ensured that many survive almost intact. The word concrete comes from the Latin word concretus, meaning compact or condensed.
The secret of concrete was reportedly lost for 13 centuries until 1756, when the British engineer and physicist John Smeaton pioneered the use of hydraulic lime in concrete, using pebbles and powdered brick as aggregate. Rumour has it that he first noticed the difficulty his workmen were having scraping a mixture of lime, water and powered brick off their metal shovels. Hmmm.
The website of the Marlbank Phoenix Tavern near us has some local history about cement. On December 11, 1890, the following appeared in The Tweed News: “Marlbank promised to rise to some importance on account of the huge deposits of marl, which have been found to extend a depth of 30 feet and over a considerable area, making the deposits practically inexhaustible.”
Well, some of that was true. The unusual soil found in Marlbank was indeed excellent for making cement, and several companies located there in the 1890s. Then, on May 24, 1900, The Tweed News carried the heading “Cement Companies Amalgamate.” I guess “Cement Companies Aggregate” would have been too much of a pun. In any event, the Portland Cement Company had consolidated its interests.
Historical photo courtesy of Helen Tuepah
Eleven kilns were used to make 500 barrels of cement a day. “The cement they made there was among the best in the world,” says Nina Jarmin. “It was used in the building of the Suez Canal.” This cement was also used in building some of the piers of the Quebec Bridge. When the bridge collapsed some years later, the only piers left were those made of Marlbank cement.
The cement plant employed about 200 men at its peak. They were paid $1 for a 10-hour day. In the empty fields opposite the factory, there were 40 residences and a boarding house that slept 100 men. Many of the boarders and workers were French or Hungarian.
Today, concrete is used more than any other man-made material in the world. As of 2006, about 7.5 cubic kilometres of concrete are made each year — more than one cubic metre for every person on Earth. The People's Republic of China currently consumes 40 per cent of the world's cement/concrete production.
The use of recycled materials as concrete ingredients is slowly gaining popularity, especially fly ash, a byproduct of coal-fired power plants that is mostly dumped in landfills. This “green concrete” significantly reduces the amount of Portland cement, quarrying and landfill space required. The high kiln temperatures create massive quantities of carbon dioxide, so cement-replacement technology such as this will play an important role in future attempts to cut our CO2 emissions.
Concrete recycling is an increasingly common method of disposing of old concrete structures. Concrete debris was once routinely shipped to landfills for disposal, but recycling is increasing due to improved environmental awareness, governmental laws and economic benefits.
Concrete can be put through a crushing machine, often along with asphalt, bricks and rocks. Rebar and other metallic reinforcements are removed with magnets and recycled. The remaining aggregate chunks are sorted by size. Smaller pieces of concrete are used as gravel for new construction projects such as the lowest layer in a road, with fresh concrete or asphalt placed over it. Crushed recycled concrete can sometimes be used as the dry aggregate for brand new concrete if it is free of contaminants, though the use of recycled concrete limits strength and is not allowed in many jurisdictions.
Recycling concrete reduces CO2 emissions, conserves landfill space and reduces the need for gravel mining.
One of our regrets in building this house is that we couldn’t find a local source of green or recycled concrete. But if enough of us keep asking, perhaps the local suppliers will begin to carry it. Maybe we should revive the history of Marlbank or be as fanatically adamant as their finished product.
MAY 1, 2009
MAKE YOUR SLOGAN GIMBY
Work on our house is progressing, as you can see in the photo below. The waste plumbing was installed, then a second layer of crushed stone on top, the slab insulation on top of that, the wire mesh, and then the piping for the in-floor heating system was installed. Once that was all inspected, we poured the floor and are now building the ICF walls.
I’ll detail the wall construction in my next post, but I really should finish my last post about site planning and vegetation as a way of decreasing your heating and cooling costs.
On a hot summer day, you can almost fry an egg on your driveway, but nobody ever tries to do that in his or her garden. That’s because plants are a lot better at buffering temperatures than concrete or blacktop. But the kind of plants you grow around your house says a lot about whether you are really sustainable or just like to talk a good game.
One plant that is definitely not sustainable is the normal turfgrass that makes up most lawns, unless you have an unconventional maintenance plan. On our farm, we sometimes tethered sheep around on the lawn. They were well fed and, at the end of the season, we ate our lawn mowers. In our new home, we are going a step further and growing plants that need no maintenance — not only in front of our house but on top of it, too.
In 1998 and 1999, the Canada Mortgage and Housing Corporation studied the time, costs and resources involved in planting and maintaining five conventional lawns versus four low-maintenance ones. Residents with low-maintenance lawns found many benefits:
• 50 per cent less time
• 85 per cent less money
• 50 per cent less fuel
• 85 per cent less fertilizer
• 100 per cent less water
• 100 per cent less pesticides per year than residents with conventional lawns
Conventional lawns are typically made up of a small number of non-native fine turfgrasses, such as Kentucky bluegrass. To keep them green and manicured, many people neatly mow them at least weekly, and regularly water, edge, fertilize and treat them for pests (insects, diseases and weeds). All of this is time-consuming, costly and resource-intensive.
These practices are not sustainable and create many adverse impacts:
• Increased water consumption. Municipal water consumption doubles in the summer, mainly as a result of lawn and garden watering. This lowers water tables and reduces stream flows, which affects fish and other aquatic life. It also increases costs for municipalities to supply and treat water and increases homeowners’ water bills.
• Increased air and noise pollution. Electric or gasoline-powered mowers, trimmers and other equipment discharge air pollutants and create noise. The Ontario government estimates that running a gas-powered lawn mower for one hour can produce as much air pollution as driving a new car 550 kilometres. Push mowers are non-polluting and better exercise.
• Increased use of pesticides. Many Canadians are voluntarily reducing their use of pesticides and some Canadian municipalities restrict pesticide use. These trends reflect growing concerns about the potential health and environmental risks of pesticides.
• Increased use of fertilizers. Depending on the types used and site conditions, fertilizers can leach into groundwater and enter streams and lakes through stormwater runoff. This has negative consequences for water quality and aquatic life. Over time, fertilizer residue can lower soil quality.
One move that will make the landscape more sustainable is Ontario's Cosmetic Pesticides Ban that took effect on April 22 (Earth Day). The provincial ban supersedes local municipal pesticide bylaws to create one clear, understandable set of rules across the province.
Pesticides cannot be used for cosmetic purposes on lawns, vegetable and ornamental gardens, patios, driveways, cemeteries, in parks or on schoolyards. There are no exceptions for pest infestations (insects, fungi or weeds) in these areas, as lower-risk pesticides, biopesticides and alternatives to pesticides exist. More than 250 pesticide products are banned for sale and over 95 pesticide ingredients are banned for cosmetic uses.
This is a sweet victory for us because 15 years ago, my wife and I tried to convince the Oakville town council and parks and recreation department to stop spraying pesticides on school grounds. We moved from there partly because of their poor record on human and environmental health.
There are some exceptions for public health, golf courses, sports fields, specialty turf, trees, agriculture, forestry and public works. Homeowners can apply biopesticides or lower-risk pesticides to control weeds and other pests on lawns, gardens, driveways and other areas around the home. However, if licensed exterminators use a lower-risk pesticide or biopesticide, they must post a green notice sign on the lawn.
This new lawn pesticide ban will do much to protect human and environmental health. But it's also becoming clear the legislation will be a boon to our economy — boosting business and creating green jobs. Communities across Canada that already have pesticide restrictions have enjoyed a major expansion of their lawn-care sector. For example, in the five years following a pesticide ban in Halifax, the number of lawn-care firms in the city grew from 118 to 180 — an increase of 53 per cent, according to Statistics Canada. The number of employees in the sector also grew.
As well, StatsCan reports the number of landscaping and lawn-care businesses in Toronto has grown each year since that city passed a pesticide ban. Ontario's organic lawn-care providers are booming. Many organic lawn products (such as corn gluten meal, horticultural vinegar, compost and beneficial nematodes) are produced right here in Ontario, which means more business for our manufacturers. By contrast, many of the toxic lawn chemicals are made in the United States or Europe.
It’s clearly time to move to a low-maintenance lawn, and that requires a shift in goals for some people from a perfect-lawn appearance designed to impress the neighbours to saving time, costs and our environment.
There are three steps involved in creating and maintaining low-maintenance lawns: selecting a suitable species mix, installation and changing to less-intensive maintenance. Canada Mortgage and Housing Corporation has information on its website about Low Maintenance Lawns and the City of Kingston has very good information about Natural Lawn and Pest Control.
Because our new home is essentially in the woods, we will encourage woodland species such as native grasses, ferns, mosses, wildflowers, low-growing shrubs and perennials. Examples could be native vinca minor, periwinkle, sweet woodruff, sweet violets, lily-of-the-valley and cotoneaster. Bugleweed, euonymus and the unfortunately named lungwort are also good candidates.
Consider ground covers instead of an unsustainable lawn. Once established, they require no work at all. Good low-maintenance groundcover plants for full-sun lawn replacement might include clover, creeping thyme, prostrate juniper, sweet woodruff, sedum and yarrow.
Whatever you choose, there are many alternatives. I know this will rile some people, but a watered, fertilized, mowed and sprayed lawn is a relic from the days when we didn’t know enough to act sensibly. Trade in your gas-powered mower and your Kentucky bluegrass for a green lawn that is friendly to children and pets and doesn’t waste our resources.
Make your new slogan GIMBY: Green In My Back Yard. You can be a good example of environmental responsibility for us all.
APRIL 1, 2009
YOUR ENERGY-EFFICIENT LANDSCAPE
The first consideration for our new earth-sheltered home was the proper site. Unless we did this step well, all the rest would be for naught, so we looked for two years to find just the right combination of features.
We needed a southern exposure for light and solar gain, with deciduous trees on the south to provide shade in the summer and allow light to penetrate in the winter. Plus, we needed a hill behind us with evergreens so we could dig into it for protection from cold winter winds. And we wanted to be on a fast-flowing watercourse so we could use micro-hydro energy generation, currently the most cost-effective way of generating clean energy there is.
We finally found the site, and we have poured footings and placed the first two courses of insulated concrete forms (ICF), which is Lego® for big boys. The forms snap together and are then filled with concrete, producing walls that are strong, insulated and soundproof.
You can see in the somewhat-distorted panoramic photo how the house is dug into the hill behind. When the walls and ceiling are in place, the piles of earth in the background will be backfilled around and over the house.
Site planning is the first, essential step in building a new house, but there are many improvements you can make in the landscaping of your existing house to make it more sustainable.
You may now be composting, recycling and walking everywhere you can. These are all good to do, but are not nearly enough to offset the environmental footprint of your house. According to Worldwatch Institute (www.worldwatch.org), buildings worldwide account for:
• 40 per cent of the world’s energy consumption
• 33 per cent of CO 2 emissions (fossil fuels)
• 40 per cent of SO 2 emissions (fossil fuels)
• 50 per cent of chlorofluorocarbon (CFC) production (refrigerants, plastics, and furniture)
• 25 per cent of virgin wood harvesting
• 16 per cent of fresh water consumption
• 40 per cent of landfill volume (construction waste)
The first consideration is energy use. You can’t really do much about the embedded energy of materials in your home, but landscaping can be designed for the purpose of conserving energy. Here are some ideas you may want to try.
Plant shrubs and trees — the right kind in the right place. Generally, you want deciduous trees on the south for shade in the summer and to let sunlight penetrate in the winter. Evergreens on the north side protect you from the cold north winds without sacrificing any sunshine.
These trees in this configuration will reduce your heating costs in the winter and your cooling costs in the summer. Trees also provide windbreaks that will reduce energy costs and provide a more comfortable yard. Windbreaks planted on the north and west sides of a building can reduce heating costs by up to 30 per cent, and a windbreak will reduce wind speed for a distance of as much as 10 times the windbreak’s height. Windbreaks also help to reduce drifting snow and soil erosion on exposed sites.
The reduction in wind velocity behind a windbreak leads to a change in the microclimate within the protected zone. Temperature and humidity levels usually increase, decreasing evaporation and plant water loss. Actual temperature modifications for a given windbreak depend on windbreak height, density, orientation and time of day. Daily air temperatures on the leeward side within 10 times the height of a windbreak are generally several degrees higher than temperatures in the open. Taking advantage of these warmer temperatures may allow earlier planting and germination in northern climates with short growing seasons. Also, in the area next to an east-west windbreak, soil temperatures are significantly higher on the south side due to heat reflected by the windbreak.
Close enough on the south side to benefit from the windbreak and far enough to be beyond the tree roots is the perfect place for your garden.
Multi-row windbreaks upwind and perpendicular to the prevailing wind are best, but even a single row of trees and shrubs can help. The windward row is what the wind hits first and should be made up of dense, fast-growing trees and shrubs that prevent snow from piling up in the centre. This also helps to prevent moisture accumulation in the spring in areas where snow is trapped and is not melted by the sun. The middle row should be made up of tall, fast-growing trees and shrubs that force winds to rise up over the windbreak. Finally, the leeward row should be made up of dense-growing trees and shrubs.
Smaller hedgerows and living fences can be used for shading sidewalks and buildings. They help reduce the heat that is reflected off asphalt surfaces and, because cool air settles near the ground, air temperatures directly under trees can be as much as 6C cooler than air temperatures above asphalt.
Select fast-growing tree species (maple, ash, cedar, serviceberry and chokecherry) and dense shrub species (buffaloberry, dogwood and viburnums). Include spring flowering shrubs and wildflowers; trees and shrubs with coloured berries; trees, shrubs, and vines with fall colour; deciduous shrubs with coloured bark for winter interest; and shrubs that have seed pods throughout the winter for seasonal interest. Use vines (Virginia creeper, American bittersweet, wild grape, virgin’s bower and honeysuckle) and perennials that will climb along a fence, trellis or wall. Use native roses and dense shrubs spaced in double rows to create nesting habitat for birds.
There is much more you can do with your home and yard, such as overhangs, green roofs, xeriscaping and reducing heat islands. We’ll cover some more in May.
MARCH 1, 2009
WHO IN THEIR RIGHT MIND WOULD LIVE UNDERGROUND?
You may be familiar with my former column, Moore from the Farm, in the print edition of Kingston Life that described some of our adventures with horses, cows, pigs, sheep, chickens, cats and a dog on our off-the-grid organic farm.
I enjoyed writing that column as much as living on the farm, but times change. Our farm crew grew up and is now in university, so my wife and I decided to take the next step toward sustainability — a step that goes beyond off-grid living.
We are now building an earth-sheltered home next to a fast-flowing rapid on a river north of Kingston. How is that more sustainable? That’s what I hope to convey in this blog, as well as suggest ways you can discover a more sustainable lifestyle, too.
Why all this fuss about sustainability? Because our climate requires too much energy to heat our homes in the winter and cool them in the summer.
According to Canada vs. The OECD: An Environmental Comparison by David R. Boyd at the University of Victoria, Canada ranks an embarrassing 27th out of 29 Organization for Economic Cooperation and Development (OECD) nations in terms of energy use per capita.
We consume double the OECD average energy per capita, and more than five times the world average. Between 1980 and 1997, our energy consumption grew by 20 per cent, slightly higher than the average OECD increase of 18 per cent.
Developing sources of energy requires energy, even if we use renewable approaches. Someone has to build and transport solar panels and wind turbines, drill for oil and build hydroelectric, oil, gas and nuclear power plants. It is clearly much cheaper to save a watt than make a watt. So, if we want to leave anything for our grandchildren, we are going to have to use less energy. That’s what an earth-sheltered house allows us to do.
When you go about two metres deep, the earth stays at a constant temperature throughout the year. In Kingston, that’s about 12 to 15 C, depending on the soil type, moisture and other factors. So you only have to heat about 5 C in the cold winter months and, in the summer, your air conditioning is free.
Since heating and air conditioning account for about half of the energy your house uses, living underground saves energy. Then, when you add a Trombe wall, solarium, eutectic salt chamber, or berm insulation (all topics we will cover in this blog) you can pretty much let nature take care of your heating and cooling needs. That saves even more energy. The next question, of course, is “Can I do this without living like a mole?” and, luckily, the answer is “Yes.” Earth-sheltered houses have been around for decades, and many designs have more light and air circulation than conventional houses. And our house will not all be underground. The current design is a hybrid, mostly underground with a small, two-storey attachment so we can see the river from our office on the second floor.
House view from the southwest. The river is outside the frame on the left.
Plus, we are building an atrium around a beautiful oak tree on the north side of the house so we will have soft, even north light and strong south sunshine.
To make this work, the first consideration is site. We don’t usually think of this with our energy-guzzling home heating and cooling machines, but our grandparents did. Look at old farmhouses — they usually took advantage of nature’s warmth from the sun in the winter and cooling from shade trees in the summer. We searched for a long time before we found a south-facing hill we could build into with trees in the right spot. In the winter, evergreens and the earth behind us will protect us from the north winds while the sun warms our south side. In the summer, the deciduous trees on the south will provide cooling shade. The next crucial part of building an earth-sheltered house is to integrate it with the landscape. Our first design attempt looked like a fortified bunker glowering from underneath green bushy eyebrows. Our second attempt looked like a shed pasted on the end of an elementary school. We think we are getting closer to what we want. Because much of the house is underground, moisture can be a problem. The roof will be covered by insulation, a rubber membrane, a root barrier and topsoil before we plant wildflowers or ground cover. The roof must be well sealed and the base of the house, the slab on grade, must be well drained.
We will have only one small roof of cedar shingles, one face of barnboard siding, and no lawn. We will reclaim and reuse as much building material as possible. Stonework will be from the building site; siding from local barns. The interior will be post and beam construction with beams from a 1915 Ottawa aircraft hanger. Reclaimed flooring will be used on both the floor and ceiling, and we have a stockpile of salvaged, 36-inch doors to provide generous openings for the time when we are playing hide-and-seek in our wheelchairs.
The primary heating system will be radiant in-floor hot water from a wood-fired boiler with propane backup. This will be nearly carbon neutral because we will harvest firewood from our site and replant what we cut. The house will be designed so we can shut the water off in the kitchen, close off the above-ground part, and heat the rest with a 60-watt light bulb if we are away for extended periods in the winter.
The boiler will also heat our hot water in the winter, and a solar hot water system will do the job the rest of the year. An air exchanger will bring in outside air and a hot water line will heat the cold winter incoming air. Then, in the summer, a cold water line directly from the well will cool the summer incoming air and condense most of the moisture.
In the small two-storey wing, a Trombe wall and a poured staircase will be just inside the south bank of windows. The winter sun will heat this mass and then, after thermal blinds are drawn in the evening, the heat will slowly radiate into the wing. A small woodstove, more for the joy of wood heat than actual need, will be in the parlour on the ground floor.
Our office will be on the second floor, looking up the river, and a dumb waiter will run up from the kitchen so we can have high tea and coffee in our second-floor sitting area without spilling on the way up the stairs. We can also holler at each other from the office to the kitchen through this lung-powered intercom.
Our electricity will be supplied from a renovated mill directly across the river that will be a showcase for low-impact, run-of-river hydroelectric production as it powers three other nearby houses as well as ours.
Water is from a drilled well and the waste system will be a Waterloo Biofilter®, a patented trickle-filter type treatment system that sprays wastewater intermittently into a patented medium and drains by gravity. Organic biomass grows quickly within the medium after start-up, oxidizing organic material and nitrifying ammonia in the wastewater. Because the Biofilter medium is contained in a tank, it is effective under all soil or drainage conditions. This is a significant improvement on a conventional septic system and was developed here in Canada at the University of Waterloo.
The cost of our new home will be about the same as conventional residential buildings but it has taken quite a lot more thought and research. Ideas have been contributed by dozens of people as we tell them of our plans and listen to their suggestions.
This is a house that is well suited to our Canadian climate and the weather extremes that our CO2 emissions are already creating.
I’ve been working on sustainability for three decades now, and I’m studying even harder to keep ahead of my students at Queen’s University. Unfortunately, we have largely lost our opportunity to reduce the devastating effects of climate change. For that, we can thank our political leaders of the last eight years who first denied then dismissed the damage caused by fossil fuels.
Most people have no idea how bad it is going to get in our lifetimes. That’s why we are building an underground home in the woods on the bank of a river with an off-grid, renewable power supply.
Once a month, I’ll keep you posted on our adventures and, along the way, suggest some tips that may help you and your family, too. I’m looking forward to your comments, contributions and questions.
Steven Moore is a commercial writer, editor and professor of sustainability at the Queen’s School of Business. You can contact him at www.moorepartners.ca.
