When carpenters are masons...

I knew from the early going that the ground floor of the house would have to be elevated in order to achieve the necessary slope to the septic system. The trouble was that the rock prevented digging down and the elevated floor wouldn’t be high enough to create a basement or even a useful crawl space without creating grading problems around the house. It was the realization that there would be no below-grade level that led me to the idea of pouring an elevated concrete slab - great for radiant heat and solar storage... but how to support it?

The options were really to pour a concrete stem wall or use some form of block that would support the slab edges while containing the stone backfill necessary to support the slab itself. Ultimately I decided to use block instead of pouring concrete because I wanted more precision than I was likely to get from a concrete foundation contractor. In my line of work - panelized buildings - close foundation tolerances are key to ensuring a fast and pain-free panel setting process. Ideally I wanted to use something the carpenters could install, that way I would be assured of precise work and I wouldn’t have to find, schedule and pay for a mason. For a while I considered using a polystyrene ICF (Insulated Concrete Formwork) but the less than ideal environmental profile of the product, along with the need to finish the exterior surface left me lukewarm.

Instead I chose “Durisol” (www.durisol.com), a concrete block made of cement and waste wood fibre. I’d used the product for a foundation a few years earlier and had been very pleased with its ease of installation and appearance. Durisol blocks are meant to be laid up dry - no mortar joints - then reinforced with re-bar and poured full of concrete, much like a styrofoam ICF. The blocks can be cut with a circular saw, and are generally friendly to all types of woodworking tools and fasteners - and thus to carpenters. They come with semi-dense rockwool inserts to increase their thermal resistance and the exterior offers an attractive textured surface that the manufacturer assures me won’t suffer from exposure to the elements.

































In keeping with my desire to perfect the layout I called Tim Rowe, my favorite surveyor, to come and lay out the building corners on the footing. If the footing had been level - i.e. the top surface all at the same elevation - and the footprint less complicated (fewer corners) - I would have been comfortable having George and Jesse lay it out because it’s easy to confirm square by checking diagonal dimensions on a flat surface. But this footing had several 12” steps in it (12” is the height of a Durisol block) as it marched up and down the site, so the potential for error was higher. Tim defined his starting point by driving a nail through a piece of orange surveying tape at the corner of the garage footing closest to the lot line, and set up his “Total Station” (a computerized surveying instrument) on that point. An hour later all the corners of the house were bang-on and we were ready to start laying block.

































While part of the plan was to avoid the hassle of finding a mason to do the foundation, George thought it a good idea to set the first course in mortar to iron out any discrepancies in the top of the footing. Luckily my first call produced results. Nick Deritis, a mason I’d worked with twenty years earlier on the very first house we built in Ottawa, was available and keen to help. Nick, now retired and without a truck, needed some help getting his mixer and other tools to the site but once we got over that he got down to business. Being of the old school, Nick was pretty sceptical about our wood-fibre concrete blocks but ultimately the light weight and ease of cutting won him over. A solid twelve hour day of mixing mortar and laying block finished off the first course for both the house and garage. The stage was now set for Jesse and George to install the horizontal and vertical re-bar and lay up the remaining courses.

























































At the lowest corner of the building the height of the foundation wall would be 6’ - or six courses of block. This scheme of backfilling behind the block with stone worried me because of the potential for shifting the block wall during the process of compacting the stone. I actually hired an engineer to think about this, and their recommendation was to do what I’d been planning all along, which was to simply brace the tallest and longest lengths of wall prior to backfilling - advice that scarcely warranted the five hundred bucks they charged me... They did also recommend tying the top of the Durisol wall into the edge of the concrete slab with pieces of 90 deg. angled rebar to permanently connect wall to slab and eliminate the possibility of the foundation wall ever shifting - a good idea that made me feel slightly better about their invoice.

The folks at Durisol also suggested that a thicker wall would be helpful in resisting backfill pressure so we used 12” block for all but the top course, where we switched to 10”. The narrower top course allowed us to move the slab edge, and the 1-12” thick strip of polystyrene that serves as a thermal break between foundation wall and slab, closer to the interior surface of the wood-frame wall where the joint between block, polystyrene and slab edge will be hidden by baseboard and won’t interfere with the final floor finish. Actually the 10” block wasn’t even quite narrow enough to achieve the desired detail so I had George and Jesse cut back the top inside wall of this top course a couple of inches to get the slab edge where it needed to be.

and God said, “build on the rock”...

With the septic and well finally in and the trees removed from the footprint of the house the next step was to scrape off the thin topsoil and expose the bedrock. My plan was to pour the footings directly on the rock, build up a short wall of block, backfill behind the block (inside the outline of the house) with crushed stone and then pour a slab on top - all of this to elevate the slab to get the proper slope for the plumbing drains to the now properly elevated septic system.

The exposed rock presented a very uneven surface with some solid ledge but also many boulders and soil-filled pockets that were difficult to remove. To satisfy a condition of the building permit I had a soils engineer come out to determine if the rock was in fact frost susceptible and the unfortunate conclusion was that it was. Covering the footings with five feet of backfill (the minimum for frost protection in our part of the world) was out of the question but keeping the heat in the ground next to the footing with rigid insulation would achieve the same result.

The first step though would be to lay in and compact a layer of gravel (Granular B - 2” minus, to be exact) to fill in some of the nooks and crannies, provide some drainage under the footings and make the job of forming the footings much easier.















The process of installing the “B” went according to plan and even offered me the opportunity to drive a piece of heavy equipment. Well not such a heavy piece of equipment, in fact it was the smallest ride-on compactor they make, but rumbling around on this thing gave me the brief illusion I was a serious contractor. After a couple of hours of this tooth rattling process, having nearly tipped the damn thing over several times, it was time to hand the keys back to the real operator and get the soils guy back out to do a “Proctor Density” test on the gravel pad.















The engineering tech showed up with a Nuclear Density Meter:

“Nuclear Density meters are a quick and fairly accurate way of determining density and moisture content. The meter uses a radioactive isotope source (Cesium 137) at the soil surface (backscatter) or from a probe placed into the soil (direct transmission). The isotope source gives off photons (usually Gamma rays) which radiate back to the meter's detectors on the bottom of the unit. Dense soil absorbs more radiation than loose soil and the readings reflect overall density”.















I hadn’t seen one of these before but I could tell from the skull and crossbones on the thing that I would be best to stand back. The technician on the other hand stood over the device with it positioned squarely between his legs. I asked him if he had any kids, to which he responded “three”. I then asked if they were normal, to which he laughed and said “absolutely not”...















With the gravel pad in and compacted to spec it was time to pour footings. I decided early on to use “Fastfoot” for the footing, a fabric forming system that is ideally suited for the uneven surface I knew was down there. Fastfoot offers the additional benefit of creating a capillary break with the ground so that moisture isn’t wicked up further into the foundation - not a huge benefit in my case with the slab so far above the footing but a real advantage with a basement or crawl space.















































































The product worked as advertised, making the job of forming footings on my sloping gravel pad much easier and faster than lumber forming would have been. Unfortunately by the time we came to the garage we had run out of the adjustable frames used to support the 2x4 rails and fabric so on this relatively flat part of the site we framed the footings the old-fashioned way and just lined them with Fastfoot to get the capillary break.

The concrete pour went well, in part because of my new neighbor Dick and my friend Barry, who just showed up unbidden at the right time with rubber boots and trowels. As the concrete set George and Jesse pounded vertical bars into the footing to fix the foundation wall. Two hours later we all stood back and stared at this dull grey spikey line of concrete snaking around the site, marveling at what was the first trace of the actual house itself.

All’s well when the well ends...

The same thinking that pushed us to install the septic first - get it done before the footings are in the way - led us to drill the well next. The whole business of well drilling is one part science, three parts magic. Some believe in witching - the mysterious process for locating underground aquifers that often involves a forked stick and a wild-eyed medium with a special gift, but in my case the location was not really up for discussion. I needed to be far enough away from the septic system to avoid contamination, close to the garage where the pressure tank would go, and in a spot that was easily accessible for the well-drilling rig - both now and in the future should we ever need to pull the submersible pump or increase the depth. So there was really only about a 20’ diameter circle where the well could go but I was still anxious to know how deep we’d end up and what the quality of water would be - in other words whether I had enough money in the budget to cover the cost.

The first step in getting a handle on what I might be in for was to talk to my friend Anthony who works as a groundwater resources engineer at the local office of a large engineering firm. I asked Ant to check the well records for properties close to mine, which he kindly did, sending me a list and cautioning that other wells in the area were not necessarily indicative of what I’d get. Sure enough the wells nearby varied wildly - my neighbour Dick for example was at 75 feet with good flow (9 gallons per minute) and no unwelcome contaminants while the house next to his was at 280’ with low-flow and an expensive treatment system for removing sulpher. I realized that there was no predicting my fate so I rolled the dice and called Troy Saunders to come in and start drilling.

There are essentially two styles of drilling rigs commonly used for water wells, a rotary drill and what is called a pounding rig. As its name suggests a pounding rig pounds a drill-bit down into the rock, the benefit of which being that the pounding opens more seams through which water will flow - a real benefit in solid rock. Pounding typically takes much longer, and thus is more expensive, so with an eye squarely on my budget, and feeling lucky, the drilling began early on the morning of Monday July 14.



An experienced well driller like Troy can tell what the gallon per minute flow rate of the well is on the fly by the amount of water bubbling out of the well head. The rule of thumb is that 4- 5 gallons per minute is a comfortable flow rate for a typical house assuming that teenage showers, lawn watering and car washing are kept under control.

Thankfully the water consumption of a typical household is changing. Where once it was assumed that a system should be sized for 100
gallons per person per day, nowadays the 20 litre per flush toilet and the 30 litre per minute shower head have been replaced by "low flow" toilets that use 4 litres per flush and shower heads that keep teenagers squeaky clean with 50% less water. Add to that the move away from manicured lawns and imported plants to indigenous natural landscapes typical water usage can drop comfortably by up to 60%.


50 feet, 75, 100, 150 - still insufficient flow. By the time we got to 200’ Troy decided it was time to try “hydro fracturing” the rock... essentially capping the well head and pressurizing the well casing with water in an attempt to open seams in the rock. By this time we had approximately 2 gallons per minute, far less than I’d hoped and by Troy’s estimation “barely adequate”. According to Troy there was always the option of moving over 20’ and drilling another hole but I had a feeling the magic seam was only a few feet further so we kept going. 225, 250... at 290’ Troy finally turned to me and said there wasn’t much sense in going further.

At this point we had by his rough calculation 2.5 gallons per minute of flow but the good news was that the water had risen to within 10’ of the top of the casing. In other words, Troy explained, the natural static level of water in the well meant that there was over 420 gallons of water in the well casing itself and even if the well was only recovering at something shy of three gallons a minute we had more than enough water to serve the house. “Good enough” said I with more enthusiasm than I felt, adjusting to the reality that we wouldn’t have the well I’d hoped for but one that, while perfectly adequate, would send us stark reminders if we ever lost our water conserving minds.

The low flow rate of the well did change one key feature of the mechanical system I’d been planning, using well water for cooling. There are several days, sometimes extending to a small number of weeks, every summer in our part of the world where cooling keeps life worth living. While this house - with it’s high levels of insulation, large roof overhangs, significant tree shading and oodles of thermal mass - may not require much if any cooling I had been planning on running cold well-water through the fan coils in both house and garage during times of unbearable heat and discharging the water to a fish-pond in the front courtyard. With this rather romantic option now foreclosed the plan will be to live in the house for a year or two to see whether cooling is truly necessary. If it turns out to be, some form of air-source heat-pump technology will likely be brought to bear.

So as required by the Ministry of the Environment the well was “shocked” with chlorine to kill biological contaminants, tagged and registered, but the testing of water quality would have to wait for the plumber to install the submersible pump many weeks hence.
Ten hours or so after he started, Troy began dismantling his rig and I began wondering what part of my budget I’d have to loot to cover his bill.

Getting started...

One of the keys to a successful project is to get the right manager. While much of the work on my job could be sub-contracted it would be essential to have a sustained presence on site to coordinate the trades and to do a portion of the work. In fact two people would be better because it’s difficult to work effectively alone, and to provide continuity if one has to be away for any reason.

About eighteen months earlier I’d contacted George Wade about running the project. George is an experienced builder and friend with whom I’d worked on projects in the past, whose skill, technical knowledge and easy temperament made him the ideal choice. I knew that someone of George’s caliber would need lots of notice so I planted the seed early. To help George I called Jesse Drerup, a twenty three year old carpentry apprentice with experience beyond his years. Jesse had spent time building panels in our shop and recently erected a Super E house for us in Korea. Despite their difference in age and experience both guys have the same thoughtful approach to their work and my hope was that the chemistry between them would make them an effective team...

The plan was to get underway in May 2008, but with delays related to environmental approval, minor variances and the building permit (I’ll spare you the details...) we didn’t start on site until July 2nd.

Actually, that’s not quite true, we began clearing trees in April. I won’t digress too far here other than to say that while micromanaging the professional arborists I’d hired to take down a few big pines, I decided to put my own chain saw to use on a copse of dead birch trees. The biggest of these trees broke in half, fell back and clobbered me, breaking my wrist and hitting my head so hard I temporarily lost my eyesight. X-rays, cat-scans, stitches and a couple of months of fogginess followed but considering the force of the blow I’m lucky the job didn’t end before it started...

The septic system saga...

By the time the Mississippi Valley Conservation Authority had defined the 100 year flood limit and the minimum setback from the Provincially Significant Wetland, the build-able area of the site was too small to allow the construction of a conventional septic system. In fact the design of the septic system - it’s size, location and elevation - had a strong influence on the siting of the house and more than anything else determined the height of the ground floor slab.

With a conventional septic system out of the question I chose a “Bionest” ( www.bionest.ca ) one of the increasing number of tertiary treatment septic systems on the market. This one combines a regular septic tank with a second tank or “bioreactor” containing two chambers - one aerobic, the other anaerobic - where bacteria break down the waste-water pollutants before the water is discharged to a much smaller than normal weeping field.


To get the Bionest tanks in we would have to break rock, so in order not to damage house or garage foundations we decided to do this first. Four hundred dollars an hour plus float charges is what you pay in our area for a “hoe-ram” capable of breaking dolomite so I took a keen interest in the installation of the tanks. The contractor hired to do the work had all of the design criteria for the system - elevation of the tanks, field etc. - so on the Friday afternoon when he declared success I was prepared to believe him... but it just didn’t look right. Rather than say
the tanks were too high, with all that would mean - lifting the tanks back out, floating in the hoe-ram, $400 an hour, floating out the hoe-ram, lifting the tanks back in - I decided to bring my level out the next day and in the peace and tranquility of a day off, shoot my own grades. Sure enough the tanks were too high, almost 20” too high, so I tracked down the contractor on his cell phone and ruined his weekend.

The Charrette...

While all mechanical options were on the table, I went into the Charrette thinking that I might like to use a Stirling Engine (see: www.whispergen.com). A Stirling Engine is a fossil fuel burning device that produces hot water and electricity. I’d first seen one being tested at the National Research Council a few years earlier and I was keen to see if it could produce all of the hot water I needed for the radiant slab or domestic use while offsetting some of the electricity we would otherwise have to buy from the local utility. Through contacts at Natural Resources Canada who had a Stirling Engine they were keen to test in an energy efficient house, I was offered a device for free and flown out to Calgary with my Electrical and Mechanical contractors to see a test unit in use. All of this background work had been done by Saturday March 1st when 15 or so of us convened for the Charrette.

The list of participants included several luminaries from the energy efficient housing community, one of whom, Bruce Gough, had prepared a detailed heat loss analysis of the design. The plumber and mechanical contractor unfortunately couldn’t make it that day but our electrician and project manager were there along with several DAC staff.

Before getting underway we made a field trip to the Snye, trudging through the snow to get a better sense of the site and how the house responded to its surroundings.

As promised, Ken Klassen facilitated the day and did a fantastic job of pushing us to consider the big issues and pulling us back from dead-end roads. In no time we had dismissed the Stirling Engine in favor of a much simpler approach that better suits a building with a good envelope. Along this line we also eliminated geothermal heat pumps and other expensive kit where the promise of lower energy costs wasn’t enough to offset high capital and maintenance costs.

Much to my dismay there was some criticism of the architecture, difficult questions about the location of the screened porch and the size and layout of the Master Bedroom for example. One of the recurring themes was that at 2,200 sq. ft. the house was just too big and if I was really serious about conserving energy I’d make it smaller. I often found myself on the defensive in an effort to avoid going too far backwards on the basic design. In the end I realized that some of these points were spot on and that it would be well worth taking a few steps back.

We had a big discussion about windows. Given the heat loss of even the best windows relative to the highly insulated walls would I consider reducing their number...? what about quad glazing? In the end I did cut back on the number and size of some and briefly considered quad glazing but concerns about the loss of optical quality brought me back to triple-glazing. No matter how lofty my goals for conserving energy, enjoying the beauty of the site took precedence.

At the end of the day we were down to an electric boiler to supply water for the radiant floor in the house. A fan-coil in the house with hot water from the electric boiler to supply hot air to the upstairs rooms. We’d circulate well water through the same coil for summer cooling and the same ductwork would serve to distribute ventilation air year round. The upstairs room in the garage would be served by its own fan-coil in a similar way. Separate Heat Recovery Ventilators with energy efficient motors (Nutech MAX Series 195ECM) would be installed in each building to exhaust stale air and supply fresh.

The “all electric” solution was favored because of the potential to use photovoltaics, whether now or later, to generate a significant amount of the energy demand. I had anticipated this approach by orienting the long sides of the house and garage to face due south, including the large 45 deg. garage roof slope. A solar water heating system (www.thermo-dynamics.com) would be used to supply much of the domestic hot water and a “Contraflow Masonry Wood Heater” (http://heatkit.com) would make use of wood from the site to supply radiant heat, ambiance and baked bread to the Dining Room. On the back side of the masonry heater a more conventional wood-burning Rumford fireplace would warm the Living Room.