Airtightness: Blower Door Testing

Excellent levels of airtightness are equally, if not more, important to the level of insulation you decide to put into your house. These really are (insulation and airtightness) the two pillars of an passive house and pretty well any other Eco-house building.

For our house, we’d gone with high levels of insulation in the range of 3x the typical amount for standard construction: R32 under-slab and basement walls, R56 walls, and R80 attic. However in deciding our insulation levels and our targeting goals for airtightness, we did try to strike a balance between cost-benefit and recognize the point of diminishing returns.

I have written about our insulation choices previously here and here, so I will not go into that as much, but in terms of airtightness there are some basics that are worth discussing. The fact is: air leaking into and out of a building is not efficient no matter how much insulation you have in the walls. Although insulation decisions, thermal bridging reduction, and solar gain can be designed into the house, airtightness can really only be ensured while actually constructing the building. Airtightness is tested with a blower door test and is rated based on “air changes per hour a 50 pascals of pressure.” Typical construction in Canada reaches about 3 ACH. The Canadian R2000, our high-efficient energy standard, is 1.5 ACH. While the Passive House standard is a whopping 0.6 ACH.

Although I was hoping we could target the extremely difficult goal of 0.6 ACH as per Passive House standard, the question was – how far ($$$) are you willing to go to reach this? As with insulation levels, there is a point of diminishing returns. Will 0.8 ACH versus 0.6 ACH be anymore noticeable in terms of user comfort? And over the lifespan of the building would you ever balance out these costs?

We decided to set an ambitious, but realistic goal, of 0.8 ACH.

The reason for this was four-fold:

  • 1. Our house is not big. It is a rectangular bungalow at 1240 sq.ft. The blower door test is an test of absolute air leakage from the building – not a relative test. By that I mean, that a large house can more easily meet a lower ACH level then a smaller house due to the greater volume of the house overall.
  • 2. We were not prepared to spend the greater amount of money on air sealing tapes, interior sheathing, and the labour to do this. A standard house is sealed with a 6 mil vapour barrier (cost is $50 per 8’x500′ roll) and Tuck Tape ($6 per roll). A Passive House is often sheathed with 5/8″ OSB ($25 per 4’x8′ sheet) on the interior to serve as it’s vapour barrier or high-end Intello Plus vapour barrier ($320 per 64″x164′ roll) with the seams sealed with Tescon Profil/Vana tape ($45 per roll). It does not take much in the way of math skills to see that the latter option can get extremely expensive. But if you really want to ensure you hit that Passive House 0.6 ACH target, that’s probably what you need to do (the Tescon Profil tape is often used on the outside walls as well to seal the air barrier and windows/doors).
  • 3. We were not pursuing Passive House certification, so really there was no point in ensuring we hit 0.6 ACH. If you’re spending the money to have a Passive House consultant work with you at the initial design stage and you’re spending the money on the high-end Passive House certified windows, the special tapes and the extra insulation, you better make sure you hit 0.6 ACH or all of that expense will be for nothing. For us, if we made 0.6 ACH, great, if we didn’t, oh well.
  • 4. We were installing a wood burning stove and chimney. Although the stove itself is very high quality from Morso in Denmark, I figured this extra hole in the wall would likely negatively impact our airtightness. But we were not budging on not having a wood stove. We also had another extra hole in the wall for the water cistern in the basement, but again this could not be avoided.

All that being said, we did make every effort to design the house to be as airtight as we could. The dense-packed cellulose in the walls itself provides a high degree of air sealing on it’s own. We limited the penetrations into and out of the house by selecting a condensing dryer from Bosch and having an electric boiler (the only penetrations are the chimney stack, the water cistern pipe, and the HRV). We used a standard 6 mil poly for the vapour barrier with acoustic sealant at every seam. Each seam was also taped with standard Tuck Tape to ensure another layer of added protection. Around the windows and exterior doors we purchased and used the Teson Profil air sealing tapes to attach the vapour barrier to the frames. Although this tape is very pricy, it made sense to me to use it here as the greatest area of air leakage is often at the window frames and doors.

Now it was time to test the house.

The testing is done through a Blower Door test. “A blower door is a powerful fan that mounts into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings.” The test is repeated in the same way by drawing air into the house. “The auditors may use a smoke pencil to detect air leaks. These tests determine the air infiltration rate of a building. Blower doors consist of a frame and flexible panel that fit in a doorway, a variable-speed fan, a pressure gauge to measure the pressure differences inside and outside the home, and an airflow manometer and hoses for measuring airflow.”

Essentially it simulates wind blowing against the house in all directions at the same time. The test takes about an hour to administer with the tester taking multiple readings at different fan speeds both while depressurizing and repressurizing the building.

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While the test was running we also used an infrared meter to look at any hot/cold spots.

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A couple days later he sent us the results: 0.8 ACH at 50 pascals.

Right bang on our goal. Not bad. The guy who tested it said it was the tightest building he’d ever tested before.

I was happy enough with it, but a couple days later I happened to be standing beside the chimney on a windy day and I could ever so slightly hear a whistle through the pipe. I looked closely at the seams and saw they were not fully sealed. Damn!

We’d also had some crappy construction locks on the doors and I put my hand against them. I could feel wind there too! Double damn!

After sealing these leaks and a few other tiny ones we found, we did another retest a couple weeks ago. This time, the results were 0.72 ACH at 50 pascals. Not too shabby.

After talking to the tester, though, he thought that given the higher than expected discrepancy between the depressurized and repressurized values that maybe the vents of the HRV had opened slightly causing a skew to occur. He’d like to do one more retest in a couple weeks, thinking this would take it down to 0.65 ACH or lower. At this point, he’s doing it at no charge as he’s simply interested to see what the truest level of airtightness is.

For me, I’m happy to know that we reached almost Passive House airtightness values while still being as economical as possible.

*** Please see the UPDATED BLOWER DOOR TEST POST for the redo test final results! ***

Solar panels – Good for the environment, good for your wallet

It wasn’t enough for us to simply reduce our carbon footprint through building a super-insulated eco-house. We wanted to come as close to eliminating our footprint completely by working towards a net zero standard. The house envelope, airtightness, passive solar design, and thermal mass of the house, would all have the effect of reducing our energy consumption by 75-80%. The rest of our energy for heating, domestic hot water, and appliances was purely electric based, with the exception of our wood burning stove. We have no natural gas to our property – and to be honest, even if we did, we would not have hooked it up. Burning fossil fuels for energy, despite it’s current affordability, is not a clean energy source nor is it sustainable. Still, despite what some people say, electricity – at least in Saskatchewan – is not sustainable nor is it clean either. Our electricity comes from a power plant that uses a combination of coal and natural gas. Really, in one of the windiest and sunniest places in the world, you’d think we should be able to have some capacity to utilize renewable energy sources. Unfortunately, this is often a top-down decision in the government and sadly, both our provincial and federal governments are heavily financed through their strong ties to the oil and gas industries in this country (no matter how much of a downturn there has been in the markets over the past year) and there is no sign of this changing anytime soon

Until such a time that the collective elite decide to recognize the need to shift away from non-renewables, it will continue to be left to the grassroots movements and local homeowners to decide if they care enough to make a commitment to renewable energy – despite the upfront costs of doing so.

But these times are changing. No longer is it purely a decision of environmentalism. Now the argument of the economics of renewable energy can be made. Let me present this in layman’s terms (as I am, of course, a layman myself).

Our projections for electrical energy consumption:

Estimated yearly energy use (DHW, appliances, heating) = 14,508 kWh (including regular wood stove use for heat)

Cost per kWH hour of electricity in Saskatchewan = $0.1456

Our projected electrical costs per year = 14,508 x 0.1456 = $2,112.36/year or $176.03/month

We worked with a company in Saskatoon, called MiEnergy, in sizing a choosing which solar array system would best suit our needs. We decided to purchased a 6.2 kW PV array. There was the option to upgrade to the 9.3 kW system but we felt that this would definitely be oversized for us at this point. The 6.2 kW system will be slightly under-sized but we can always add on more panels at a later date if we so choose.

6.2 kW system delivers an average of 775 kWh/month = 9330 kWh/year on average

That provides us an immediate saving of $1358.45 per year ($113.20/month) in energy costs. Expanded over the course of a 25 years this delivers $33,961 in electrical savings at the current electrical rates. (I found an interesting article on the energy outlook in the U.S. – there has been a $0.04 cent rise per kWh from 2003 to 2013. Extrapolating that, conservatively, over the next 25 years we should expect an upwards $0.08-0.10 rise per kWh. That equals between $0.22-0.24/kWh. The projections from MiEnergy pegs the 30 years saving at $58,067).

If you take the cost of the PV panels and roll this into a 25 year mortgage at a current 3.19% interest, this only costs a meagre $110/month. So essentially instead of giving $113.20/month (currently, which will increase) to the government to cover our extra electrical bill, we will invest $110/month towards the PV panels on our mortgage. After 25 years, they are paid for and we have money in our pocket (not to mention the fact that we’ve saved 233,250 kWh of energy from being generated at a polluting power plant). That’s a win for us and for Mother Nature.

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If you want the facts and economics only, then disregard the story that follows. Of course, I wish my post, could be that short and simple. But as I’ve learned with building the house – something always goes wrong – no matter how bizarre, stupid or impossible it might seem…

The above photo is the after shot. After I received the phone call at 6pm on a Friday night from Saskpower (the electrical company) asking why a large steel beam had been driven directly through their power line?

“Uh… I don’t… know?”

You see there is this thing called: “Call Before You Dig.” It’s a free service that most places have that asks that you please call them to mark your underground power and gas lines before digging so that you don’t kill, maim, electrocute or otherwise dismember yourself. Unfortunately, as we learned that night, it is not a perfect service.

The solar company had called and had the power line (note, the singular word: line) marked a couple of days before the planned installation. Unfortunately, there were in fact, two power lines running into our transformer, one from our neighbours place to ours and the other running from ours to about 60 houses over the next number of miles. Well, you guessed it, they hit the one running to the 60 houses (that was not marked), knocking out their power for the next 8 hours. Oopsy.

IMG_3040When I showed up to the house, you could see the one line that was marked (as it was prior) with the solar panel racking system 4-5 feet away, then you saw where they had discovered the 2nd line, lying directly underneath the 2nd row of racking (not previously marked). The Saskpower guys though were very good, they realized it was not the fault of the solar company, nor mine, the line simply had not been marked by the Call Before You Dig people. They were just glad that no one had been hurt. They were able to restore power to the 60-odd houses that had been affected and the next day they were back out to splice and move our newly rediscovered power line.

(Incidentally, this was a total blessing, had they actually marked both power lines previously, we would not have been able to put the solar panels where we had wanted them. We would have been forced to find another, less ideal spot a much greater distance away).

By the way, we have had a number of people ask us why we did not choose to utilize a solar thermal system for water heating. Basically, it was because of this article and this article on Green Building Advisor.

SUPER-insulation! Airtightness! The staples of a passive house.

There are seemingly innumerable weighs of building a super-insulated home. Once you venture outside of the conventional 2×6 walls with 1-2″ of EPS foam, there suddenly opens of a plethora of options. I won’t go into as I’ve talked about it before, in us choosing super-insulated walls system and the double-stud deep wall framing. Now what you put between those walls is just as important as how you construct those walls. In our case, we chose to use dense-packed cellulose.

Cellulose insulation is a made from recycled newspaper or other wastepaper and treated with borates for fire and insect protection (taken from GBA). Dense-packed cellulose is really, just what it sounds like: They pack it like crazy into the wall cavity – but not too crazy. In fact, the ideal balance between too loose and too dense is about 3.5 lbs per cubic foot. If it is too loose it will settle and result in poor insulation over time. The denser it is the more resistance to air leakage (the vapour barrier obviously reduces this further) and the better the insulation. However beyond about 4 lbs per cubic foot of density you are at risk of blow-outs (or the drywallers will not be able to work with your crazy wavy walls).

At 3.5 lbs per cubic foot and with 16″ thick walls, our R-value is a whopping R56 for the exterior above-grade walls!

We contracted a company, Westcan Insulators Inc., who has extensive experience with super-insulated homes and a wealth of knowledge in energy efficiency. At our preliminary meetings they provided us with so much valuable information (have preliminary meetings with all trades presents – it truly is invaluable). It was so reassuring to have them on board, as really in building an energy-efficient home, the insulation and airtightness are the most important aspects. If you don’t have this right, you really don’t have anything.

As Rob Dumont said: “Anything that has moving parts will fail; in fact, it must fail, because there is no such thing as a perfect bearing.” Therefore, passive systems are always better than active systems and insulation and air sealing, if done well, will have the greatest return (for the lowest cost) over the lifetime of the building.

So here’s how the process worked:

On day 1, the crew came in and wrapped the walls with InsulWeb, a mesh that holds the dense-packed cellulose in place while spraying. They go through a buttload of staples to hold this onto the studs. They have to put a staple every inch along every stud, so you can imagine how many staples that would be. Crazy.

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The next day, they bring out a big 5 tonne truck and using a 3″ wide metal hose they make a hole at one-third and two-thirds of the way up each stud bay. They then proceed to essentially filling the walls with the entirety of the truck. In actual fact, they unloaded about 6000 lbs of insulation into the walls alone (holy crap!).

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Here is a close-up shot of the cellulose and penetration. You can nearly read the newsprint.

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The next day came the vapour barrier and air sealing. This actually took the better part of five days for them to complete, but they did an excellent job (by the looks of it – we will really find out when we test it with a blower door in the next few weeks).

Airtightness is really equally as important as the insulation – perhaps even more so. Air leaking into and out of a building is not efficient no matter how much insulation you have in the walls. They used 6 mil poly for the vapour barrier with acoustic sealant at every seam. Each seam was also taped to ensure another layer of added protection, though truthfully this is probably unnecessary (from what we have been told, with this insulation alone, without the vapour barrier, would surely pass the R2000 airtightness requirement of 1.5 ACH @ 50 pascals), but it’s not hard to do and once the drywall is up you can’t go back and add more.

Around the windows and doors though we spent a bit of money and purchased Tescon Profil tape from 475 Building Performance. The stuff runs at $45 per roll, which is certainly a premium price versus the $9 per roll of good ol’ Tuck tape (the latter of which we used around all other seams). However between the walls and the windows/doors, there isn’t the layer of protection of the dense packed cellulose insulation (although they did spray foam around each window and the rough opening), so we felt the extra price could be justified here (to do the whole house in the Tescon Profil tape would be simply cost-prohibitive [although some people do it]. For the marginal gains you “might” make in airtightness, you would never save enough money on the long-term to justify that huge upfront cost, in my humble opinion).

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Expensive fancy tape.

Main Floor Concrete

We were very happy with how the basement concrete slab turned out. Tyco Concrete had come through for us on short notice and they had done a really nice job. So one week later we had them come back in to do a second pour, this time for the main floor. We had really debated about how we would like to finish the main floor concrete though despite months of reading and looking.

I should digress for a moment and simply state our reasons behind the concrete floor in the first place:

  1. Thermal mass – thermal mass is a the ability of a material to absorb and store energy (heat in particular). For passive solar heating in the winter months, the sun shining on the concrete will act like a battery, gaining heat during the day, and allowing it to release the heat in the evening. You could use a tile or brick to similar effect. A large brick or stone wall would also work, but you need the sun shining on it. Conversely, in the summer and “shoulder” (April and October) months you really don’t want the sun shining on the thermal mass as this can lead to overheating (thus the importance of passive shading and overhangs).
  2. In-floor heating – we still need a heat system. It is true that our thermal mass is not quite as good as if it had no in-floor heat (a colder mass will heat MORE than a mass that is already pre-heated) – however who wants to walk around on a cold concrete floor in the morning, honestly?
  3. Concrete is sexy.

Okay so now that that is cleared up, we had to decide on how we would like to eventually finish the floors. We had already decided that acid staining and dyeing the concrete was really not our thing – much too fancy-pants for us. That basically left us with two options: power trowel (same as the basement) or grind and polish. Both looks we really like.

Grind and polished concrete – not our place

The grind and polish look is something I really like. You need a concrete grinder machine with diamond discs starting with very rough grits of 80 and 120, which grind the top layer of concrete off exposing the pea gravel aggregate that sinks to the bottom and progressing up to finer and finer grits. Eventually getting up to 800, 1200, 2000 grit discs that give a highly polished look to the floor. You get a lot of interesting variation and different colors of the pea gravel coming through (although some people specify all grey or black pea rock if they want something more consistent). There is a couple downsides with this for us though. Firstly the concrete topper they were going to pour was only going to be 1.5″ thick, which is pretty darn thin. Although you are only taking about 1/8″ or so off the top, we had 1/2″ PEX in-floor piping and metal concrete mesh overtop – grinding too much off could be a horrible thing. We had seen this first hand – a good friend had built an eco-house in town and wanted a ground and polished concrete floor. Unfortunately the contractor ground off about 1/4″ too much. It looked great initially, but the layer of concrete over the in-floor heat was so thin that in the next few weeks the concrete started to crack badly following the pattern of the in-floor lines… It looked so bad. On a thicker floor you’d have nothing to worry about, mind you. But needless to say I was a bit paranoid of that risk. The second consideration is that you need to grind and polish before drywall as it makes a crazy mess. And you can’t grind and polish until it has cured for one month. That would mean that we would have to put the interior on hold for a month which we really did not want to do.

The other option was to simply power trowel the main floor, same as the basement. We have seen this look a lot in some more modern homes and I really like the simplicity of it. It is not complicated at all and is in fact the simplest, cheapest and easiest way to go (pour and trowel is about $2.50/sq.ft completed while the the grinding and polishing cost would be an additional $5-6/sq.ft above and beyond). You pour floor, power trowel the crap out of it and call it a day (in 28 days you can seal it, buff it, wax it, whatever). As I said we liked how the basement floor turned out, particular the very “swirly” areas, as my wife calls them. I hoped that we could make the floors slightly different then the basement floor still though. I looked into the possibility of adding a bit of black pigment to darken the grey slightly – however I abandoned this idea after I was told the pigment dries the concrete faster and can lead to an uneven finish.

Eventually the decision came down to, what is the simplest option? Through this process we have found ourselves periodically down a rabbit hole wondering how we got here and how everything became so complicated. Our answer in those situations, or when we’ve debated about two or three different things is – simple is always better. The more complicated, the more things can go wrong.

So I told the concrete guy, “finish the concrete just like the basement – only, more swirly please.” (He told us that the metal blades of the power troweled as what make it swirled and darker, but troweling longer and on a higher speed for the blades, they can darken the concrete more).

The morning of the pour was crazy again, our builder did not realize they were coming so early with the concrete truck and he’d left a bunch of stuff around the house. I received a text at 6:30am from the concrete guy – “someone has to get over here and move all this shit – truck is here.”

IMG_2982Fortunately we are living very close right now so I threw on some clothes and was out the door. We frantically (concrete starts to cure as soon as it leaves the plant – being 30 minutes from the city, every extra moment counts) moved a trailer, two big garbage bins, scrap wood, plywood and all sorts of junk. Meanwhile the rest of the concrete crew was even more frantically throwing down the concrete mesh (which provides structural support, like rebar, in thinly poured floors like ours). This stuff was crazy heavy and looked so cumbersome to work with, but these guys were pros, they had the whole floor laid and secured in about 20 minutes.

And so the pour began again. I could not stay and watch and truthfully, I did not want to see it. Seeing that grey/brown sludge of mud being rolled in and dumped on the floor simply made me nervous. I just wanted to see it pretty at the end.

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When we got home all was quiet again. We went to the back door and peaked our heads in.

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So swirly!

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So very swirly!

High performance windows installed

Windows are one of the most critical elements of a Passivhaus and any super-insulated energy home. The placement of the windows, the type of glazing, the type of coating, and the frames all have an integral role in how much or how little energy your home will use. But what most energy aficionados consider to be the most important is the frame. For us, the only real option was fiberglass. Most regular home install run of the mill vinyl, wood or metal – but these materials are simply highly inferior to fiberglass when it comes to energy performance.

“Fiberglass is created by pulling strands of glass through a heated die, resulting in a material that is strong, resilient, and suited to all weather conditions… Energy efficient frames have low conductivity that discourages the transfer of heat or cold into a building. Fiberglass has a much lower conductivity than metal options; simply placing a hand on a fiberglass frame compared to an aluminum frame in -20°C weather makes the difference very clear… Fiberglass is much less conducive to allowing cold temperatures to pass through the frame, thus helping to prevent condensation and loss of heat… Subjected to temperature extremes, windows must remain stable, with minimal expansion and contraction to keep an excellent seal. Considering that the bulk of a window is glass, what better material to surround it with than glass? Hence “Glass on Glass Advantage”. Composed of about 60% glass, fiberglass, like plate glass, has a very low rate of expansion and contraction. Fiberglass maintains an excellent seal with reduced movement relative to the plate glass. Superior stability also results in greater longevity, fewer seal failures, and better paint adhesion.” -Duxton windows

Although we are targeting Passivhaus performance levels for our house, actually purchasing “Passivhaus Certified” windows was simply far too cost prohibitive (~$90/sq.ft.) and must be shipped across the ocean from Germany (that is a big carbon footprint to overcome). There is one Passivhaus manufacturer of windows in Canada that I’m aware of called Northwin, but we didn’t pursue a quote from them, the only reason being is that no one around here had any experience with them, and from what I was told the cost was extreme. I had wanted a recommendation or at least a review from someone who had worked with, lived with or installed them before.

One of our friends had built a very energy efficient house and installed Fibertec windows out of Ontario. Although they were beautiful looking windows, they had nothing but problems with them (air leaking, condensation). My thought is that these windows, made in a warmer part of the country, were not designed with a cold prairie climate in mind (I have no evidence to prove this, mind you). As such we avoided any manufacturers outside of our climate zone. That basically let us with two fiberglass window manufacturers: Duxton windows and Accurate Dorwin, both from Winnipeg MB.

We knew people who’d either installed or worked with these windows before and each of them were happy with them. We received quotes from each of them and they were essentially equal (Duxton being $500 more). We ran the two windows through the energy modelling software and Duxton came out the winner. I’d also talked to a Passivhaus engineer who’d found that Duxton “performed very well in the PHPP.” My wife also liked the name “Duxton” better.

They are a pretty impressive and innovative company. We actually met the owner, Al Dueck, and had a drink with him at a Building Green conference a few weeks ago. The company has recently developed a quintuple paned window! Five panes with a rating of R20! Outrageous.

We ordered the windows way back in early May, before the ground had even been broke on the foundation. I’d been expecting this to be more than an ample amount of time for them to be fabricated and delivered. Well, I was wrong. So very wrong. Although I was told that they would be ready in 6 weeks, they weren’t actually delivered and installed for nearly 10 weeks. Fortunately for us, our builder and the subcontractors were willing to continue on and not wait.

We had everything coordinated when they confirmed at last that the windows and doors had been sent out. Our builder, received the shipment, unloaded them and said “WTF!” We were missing all of the doors and one of the largest windows. It was the end of the day and we scrambled to try and find out which of the three shipping companies may have lost them… but all of them confirmed, when I called them frantically, that they had received the same items. It wasn’t until the next day that we received a sheepish email from Duxton that they had “forgotten” to ship them. Oops!? What a headache.

Not only were we trying to coordinate the shipping, delivery, installation of the frames and smaller windows, but also the “site glazing” (6 of the windows were too large and heavy to be sent as a single piece, therefore the glass and frame were sent separately and had to be installed by another subcontractors). Basically there was a lot of pieces that had to fall into place. And none of them did. But after hours on the phone rescheduling everything, like most (kind of) things, in the end it worked out. The windows and doors arrived and were installed. And they look super sexy.

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Frames only. Waiting for site glazing.
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The triple pane pieces of glass. These made me so nervous. I did not want to be around when they were installed.
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Almost all installed. Note – no door and no window on the far end.

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Basement concrete slab

I do love concrete. It is one of those rare man-made products that border on being a living thing, like plaster or linen.  Those things that have such a rich texture and variation of composition that they seem to beckon you to touch them and get up close for a better look.

Of course, not everyone will share my appreciation of concrete, traditionalists have tended to cover up the concrete or at least extensively treat it with stains and dyes making them more palatable to themselves. Not us. When I told an interior designer about our exposed basement concrete walls, his response was, “Now that’s modernism with a capital ‘M’!” Cool, I said, “What’s modernism with a little ‘m’?” To which, he sheepishly did not have a response (I’m an ass).

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After the walls cured for 28 days, we had to seal the concrete. We wanted to get this done before the slab went in because if we waited to do the floors and walls at the same time, not only would there be framing and drywall in the way, then we ran the risk of the drywallers slopping crap all over the walls and making a mess of our beautiful concrete finish.  Like an idiot, I decided not to purchase a $25 dollar wand sprayer to apply the sealant and instead decided to use a nap roller. A job that would have taken me 30 minutes ended up being closer to 5 hours rolling every inch of the wall on multiple passes (lesson learned).

Next, we had to lift the giant water tank and Japanese soaker tub off of the floor and strap them to the steel beams (getting the tub in the basement was another adventure in and of itself. I will write about that someday). The under slab insulation was then cut and laid. We elected to use 7.5″ of under slab insulation, which is likely overkill, however this brings the floor insulation to R30 (our last house had no insulation in the basement at all). This EPS insulation was pretty cool. Having a honeycomb pattern as the top layer allowed for incredibly easy installation of the PEX piping for in-floor hydronic heating.

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Notice the levitating water tank and soaker tub

We knew we wanted the concrete floors to be a simple natural grey concrete, power troweled and sealed to complement the exposed concrete walls. No fancy finishing, dying, staining or grinding.

Now being that the basement concrete slab was to be our finished floor, it was pretty important to me that it not look like crap. Therefore the quality of the contractor needed to be top notch. Unfortunately for us, that was not how we entered into this venture.

I did not meet the contractor before he was actually on site prepping to pour. My wife had driven home early that day and came upon a most peculiar sight. A rather criminal-looking fellow standing beside a broken down early 1990s sedan, holding booster cables. Our place is a bit out of the way, so this was not a sight one would expect. Of course she stopped to see what the problem was (as the next passerby would probably not be until much later on). He proceeded to tell her that he needed a boost, he’d gotten in a fight with his boss and left from “that house being built down there”, pointing in the direction of our house. My wife, boosted his junk car, and asked if he was going back to work? Nope, he said, and drove off.

My wife drove to the site and found a lone guy working in the basement – no truck, no car, no nothing. She told him she might have just met his worker on the road and asked how he was getting home. Of course, he had no idea. She called our general contractor to come pick him up, however as she was leaving the property his buddy had returned with the car.

When I stopped by later to check on the whole situation, they were still there.  “Working late, boys?” I asked. “Yup,” the boss said, “but we gotta get home, we’re losing light and we don’t have any headlights.” (He wasn’t joking).

He told me that they were planning to have the concrete poured in two days, but would need to finish laying the rebar and tying everything in beforehand. “I’ll be back at 6am tomorrow,” he said, before driving off headlight-less into the night. I came by the house at 7:30am and, not surprisingly, they were not there. Sometime throughout the day however, they were back working away in the basement – this time, they’d brought a rusted old Honda, apparently this one had headlights and was more reliable.

On the Thursday, which was the day of the scheduled pour, they did not show up at all (what other profession could you simply not show up to work and there be no repercussions?). The bossman called our general contractor later in the day, apologizing and saying that he had to fire the criminal looking guy, but promised to complete the pour the next day. I told the contractor that it was tomorrow, or else he was off of the job.

On Friday, I received a phone call from them telling us it was “too hot” to pour the basement slab. Granted it was 34° Celsius. He said that the concrete would cure too fast and they would not be able to guarantee a nice finish. I wondered to myself – is this a convenient excuse for them in case the floors didn’t turn out? What am I to do? Ask them to pour it anyways? I called a couple of friends that I have in the concrete business and asked if they were pouring today. They were. I asked if there would be any reason to not pour a basement today and they told me that an insulated basement would be perfect in this weather – being at least 10 degrees cooler in there and not in direct sunlight.

That afternoon, we made calls to find a replacement for this retard concrete guy. I couldn’t handle it anymore – how many chances do you give someone? That being said we needed the floor done immediately. This idiot had already setback three other trades with his 5 day delay. Especially when Taylor and Curtis worked to hard to be ahead of schedule despite some of the challenges they faced with the Nudura One set up.

Incredibly we talked to Tyco Concrete Finishing, who said they would be able to squeeze us in early the next week. That Sunday evening we met the owner on site (I was relieved to see him drive up in new super duty 4×4 truck). He spent a couple hours with us going through everything, including checking what little work the other guy had done, making sure he knew how we wanted it finished, and confirming all of the dimensions and depths.

Two days later this was happening:

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They had a crew of six guys on site and they did an awesome job. That night we came home to this.

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The importance of the roof and the cruel truth of overhangs

The roof is what really gives a house it’s personality. Christopher Alexander writes in the Pattern Language No. 117: “The roof plays a primal role in our lives. The most primitive buildings are nothing but a roof. If the roof is hidden, if its presence cannot be felt around the building, or if it cannot be used, then people will lack a fundamental sense of shelter.”

We had really debated about doing a house without overhangs, which when scouring design sites, we had seen a lot.

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I really like the look of these types of vernacular houses, and we came very close to building something along these lines. However, we were talked out of it – or perhaps, talked into proper overhangs, by our engineering team, Integrated Design. They were very adamantly against the “no overhang” aesthetic that we were drawn to. Granted they had some valid points including: adequate shading in the summer, protecting the siding and windows from rain and excessive moisture, and keeping water away from the foundation. Grudgingly I did some of my own research and dammit they were right. This article from Green Building Advisor shamed me for doubting the importance of overhangs. 

Although I was drawn to profiles of houses like those in the above photos – our most favourite house is called the “Stockily in Balsthal” by Pascal Flammel Arkitekten.

Stockli in Balsthal

Now those are overhangs. This house is just so badass (granted, this house has very large windows on the gable ends that have absolutely no shading – which would certainly lead to overheating). For our house, being only a bungalow, we could not have as crazy intense of overhangs as this place – but still it served as good inspiration – and also got some good eye rolls from the engineers, when we would tell them, “well, if we can’t build a house without overhangs, then we want this!”

After playing around with solar studies in the computer program and tracing the path of the sun with our GPS location we found that the optimal overhang width – that would give complete shading in the summer, ultimate solar gain in the winter, and still looking badass – was a 48″ overhang. Most roofs in this part of the country are 12-20″ wide so 48″ is quite a statement. I loved that fact that it balanced the aesthetics with the practicality of overhangs.

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Side door rendering

But I was not sure how this would really look until the guys got the rafters up and in place. At 38′ wide and nearly 20′ tall the rafter company had to send a special truck out to deliver them, which I took as a good sign that these were going to pretty be unique.

The day after the walls were framed, we came home to this:

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By the next day the interior walls were framed and roof was nearly completely sheathed.

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Two days later the standing seam metal roof was on. The house was looking pretty darn badass, I’d say.

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Double Stud “Deep Wall” Framing

The day following the completion of the excavation, backfill, grading and dirt hauling, Taylor and Curtis with EcoSmart got to work framing the double-stud exterior walls. We had chosen to use the “deep wall system” originally developed by Rob Dumont, a local Saskatoon engineer who is widely recognized as one of the pioneers of super-insulated green building. He has been a major inspiration to the owner of EcoSmart Developments, Murray Guy.

Rob Dumont had been one of primary engineers in creating the Saskatchewan Conservation House – which is one of the original homes that inspired the German Passivhaus movement. This is a fantastic article about Rob Dumont’s own home that he built in 1992 using his deep wall system (it was considered to be the most energy efficient house in the world at the time!).

Saskatchewan Conservation House, 1977
Rob Dumont’s personal home

Rob Dumont developed this super-insulated wall system and Peter Amerongen from Edmonton AB has been perfecting it over the past few years, using it in the Riverdale NetZero and the Mill Creek NetZero homes, amongst others. To my knowledge, no one since Rob Dumont himself, has built another home in Saskatchewan using this type of wall system. I’ve written about this wall system previously, but now we were going to see it come to life before our eyes.

Taylor and Curtis had of course never built this type of wall before, but they had done extensive research and were very motivated about it. This wall system utilizes two 2×4 walls, spaced 16″ apart thereby creating an 8″ void between each 2×4 wall. There is no need to offset the studs as the large void, which will be filled with dense-packed cellulose (recycled newspaper), has no thermal bridging whatsoever. We elected to space the 2x4s at 16″ centers for both the interior and exterior walls. It is possible to space the non-loading bearing wall at 24″ centers, but when attaching the wood siding to the exterior wall (our non-load bearing wall) this might be a little more tricky.

Of course this wall system takes a bit longer to construct then your typical stick-framed house, as each wall needs to be built twice. What the guys did was to lay the lumber one on top of the other to ensure that the spacing was appropriate. The studs were nailed together with a double bottom plate (we will be pouring 1.5″ of concrete for the main floor so you another bottom plate was needed in order to secure the drywall to it) and a double top plate. The two walls were then secured to a 16″ wide 3/8″ OSB header and footer and tipped up into place using wall jacks. The walls were then glued and nailed into place and sheathed on the outside.

The first day they framed the west wall which is 30′ in length. Honestly, the excitement of seeing a wall could not be contained that day.DSC_0316

Side door with transom overtop
Side door with transom overtop

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Day two they framed the north side which is a longer 48′ wall with minimal penetrations – one window in bedroom, one in the hall for ventilation and the back door.

Day three was the west wall, again 30′, which included three large windows (energy efficient geeks will note that there is minimal benefit to large windows on east side and there is risk of overheating in the Spring and Fall) however these windows look onto an amazing river view that we had to enjoy. The windows will be glazed in a special coating to reduce heat gain (more on that later).

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Looking east to the river
View from the kitchen sink
View from the kitchen sink

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Main entrance and foyer corner window
Main entrance and foyer corner window (tricky detail)

Day four they ambitiously completed our southern wall, our primary 48′ wall, with three MASSIVE windows – all of which are more then 10′ wide – and a patio door to the deck. This side of the house looks onto a beautiful southern view across the river valley, but also will be a source of heat gains in the wintertime.

Four walls!
Four walls!
HUGE south windows
HUGE south windows
Dining room corner window
Dining room corner window
Framing details
Framing details
Corner window framing details
Corner window framing details

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Next would come the interior walls and roof – and suddenly this was looking like a house!

Water Tank and Foundation Finishing

DSC_0472We finally decided at 1pm on Monday that we were going to do the water tank in the mechanical room. We had went and viewed our neighbours set-up and talked to him about his experience. It all seemed good enough. But meanwhile that morning, the crane had shown up and lowered the giant steel beams into the walls of the foundation.

I had watched the crane go to work in awe like a little kid – “Woah, a crane!” It was pretty awesome to see the crane towering over our trees and lowering the steel beam into the grooves that Taylor and Curtis had left when pouring the concrete a couple days earlier.

It was an impressive sight to see.  The slid in so effortlessly.

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Within a few hours, the guys were hanging the joists and starting to the lay the floor. You’ll notice that the beams and all of joists are within the envelope of the foundation walls. This was intentional from an energy efficiency point of view. There is no thermal bridging at all with this system. Oftentimes typical houses are built with the joists sitting on top of the concrete wall or on a ledger of the wall. Both of these are a bit more work then simply using hangers. And the former, requires excessive use of spray foam to seal.

The way we did it required a taller basement wall, but there is zero chance of air leakage, thermal bridging or heat loss with this.

Anyways, the carpenters were working fast. Crap, Darcie and I realized, we had to decide immediately whether or not we were going to have the water tank in the basement. The carpenters were going to be done the floor system the next day, which meant that the tank needed to go in the basement NOW.

I made some calls and found a manufacturer east of Saskatoon who sold large tanks. We hopped in the truck and  made the 45 minute drive. We had debated briefly about what size of tank to get – essentially everyone we talked to told us to purchase the largest tank that would fit in the house. That meant we could get a 2100 US gallon tank – measuring 88″x88″. If you can’t picture that, well, it’s big.

We drove back to the land and within a couple hours were ready to haul the giant beast of a tank into the basement…

Only problem was the crane was long gone, and there was a huge gorge – 11′ deep and 6′ wide – all around the perimeter of the house. The four of us put our heads together. We all agreed this would have been a LOT better to have done when the crane was here… Crap.

The options were slim. The only possible way was to jimmy up a rickety makeshift bridge between the foundation and the ground using 2x10s and some left over joists. We decided to push the tank off of the trailer (there was no way to carry it) and roll it to the side of the gorge. From there we wrapped two large ratchet straps around the top of the tank and lashed them to the back of my tractor.

Now came the dangerous part – Taylor and Curtis pushed the tank onto the shoddily crafted bridge (one false step would mean certain death or at least dismemberment) while I slowly backed up the tractor thereby keeping tension on the straps and allowing the guys to ease the tank across the “Bridge of No Return.” My wife cringed as she watched the bridge bow under the weight of the tank and guys.

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Miraculously no one was killed. Not even a little bit.

Once we had the tank to the edge (Taylor had also built a small ramp on the inside of the foundation), I could simply back the tractor up and lower it down.

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That went well.

By the end of the day, the guys had the floor framed – pretty impressive. They’d poured the basement on Friday and floor was framed and sheeted by Wednesday. Time for a dance party.

We all grabbed a beer to celebrate and as we were standing there, an eagle flew by carrying a fish.  We were all in awe and Curtis said “and this is where you guys live?”!  It was awesome.

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PS. One more geek/nerd energy efficiency thing: They wrapped the house in the water proofing seal, but also wrapped it up and around the plywood to create a complete seal around the entire basement. It is possible that a small amount of air leakage could occur through the plywood and the top of the joists and foundation wall. This simple trick tightens the house up even more.

Concrete wall reveal

The day following the pouring of the concrete, we were ready to pull off the plywood forms and see what lay beneath. Leaving the plywood on for more than a day would cause them to adhere too firmly to the concrete and make them extremely difficult to remove. We were a bit nervous. We had been pegging a lot on how these walls would turn out – they would be, after all, our finished interior walls, so I really hoped they wouldn’t look like crap.

First we had to remove all of the exterior bracing that the builders had spent four days installing, tweaking, levelling, and straightening.

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They had done a great job. The walls were perfectly straight and square.

We started unscrewing the plywood forms and Cha-Ching!

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They looked frickin’ awesome!

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As we removed the forms, I had to chuckle, because the builders, who had for the previous week been cursing the Nudura One system, as they saw the finished look decided the would “use it again.” I guess looks due make up for a bad personality from time to time.

We spent about two hours removing all of the forms. As we got towards the base of the floor, we crossed our fingers hoping that it had all settled nicely to the bottom without any “honey combing” of the concrete that would need to be parged. Impressively, it looked excellent all the way from top to bottom.

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Dang, those are sexy walls.