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.

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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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!).

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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.

Foundation/Basement Forming

Meanwhile, the foundation work continued to move forward. A few weeks ago I’d written about the Nudura One Series of ICF. We were quite excited about it for a number of reasons. Firstly, basements are generally BORING. So, with using this system of ICF we could have a finished interior wall of concrete immediately, which would look aesthetically pleasing and be something of interest and uniqueness in the basement. No need for any extra framing and drywall. Second, in terms of energy efficiency, this system should perform better than conventional ICF. You are not insulating the walls of the basement from the house itself (standard ICF and standard poured basements have insulation on the inside and cannot use the thermal mass of the basement walls). Being that we have a huge thermal mass in the walls (and floor) of the basement, they can store a lot of heat to radiate to the rest of the house either through sunlight or simply from the in-floor hydronic heat. Essentially functioning like a giant battery.

About a week prior the forms had been sent out. There was an incredible amount of insulation that was stacked in the shop.

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And the day following our stresses with the septic system, Taylor and Curtis got to work building the basement forms. They had budgeted about four days to get the forms up and one day to pour. ICF goes fast, they said.

… But not this ICF. This basement was a massive pain in the ass. After one day, the guys only had one row of the seven done. There was no simple way to attach the forms and keep them locked in place. You see, in standard ICF, the blocks are basically like Lego. There are little grooves on the inside and outside that line up and attach to the corresponding little plugs on the other block. Snap snap snap, it goes together. Easy.

Typical ICF

This was not easy. The little Lego grooves and plugs were only on the outside of the blocks. Not the inside,  as the plywood slabs simply butted together creating big seams and gaps (wouldn’t tongue and groove plywood have made sense, Nudura!?). Frustrated at the lack of progress, Taylor called the Nudura sales rep who came out to the site. Amazingly, he had never seen the Nudura One series before. Like never ever. As they all worked together to try and troubleshoot this problem, they eventually decided to call the head office in Ontario, Canada and their technical support team.

IMG_2544They suggested make 2×4″ L-brackets to support and anchor the forms (uh, that’s part of the plan?). Oh and as for the gaps in the plywood? (Where concrete would completely burst from when pouring.) Well, just use Tuck Tape, they said. Tuck tape!?? (I suppose it’s slightly more classy then duct taping the forms). Jeez Louise.

Unfortunately, after building a bunch of the 2×4″ L-brackets and bolting them onto the forms, the carpenters realized that this was not going to work at all. These brackets did nothing and if anything made the problem worse by pulling the forms further inwards, causing even greater warping of the walls. Thanks for the “technical support”!

(You’d think they’d never sold this product before – which, later we found out they have never actually used it in a residential application!)

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Over the following four days, Taylor and Curtis grudgingly put the forms together and stacked them higher and higher, eventually reaching the top at 10’6″. They put an absolute tonne (perhaps 2 tonnes) of rebar in the ICF both vertically and horizontally to reinforce the high walls and provide the structural support for the beams, joists, and double wall that would sit upon it. Seeing the forms go up was pretty exciting, but just don’t look too closely or right down the line of the wall…

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Because that ain’t straight.

I have to admit, I was more than a bit worried. How the hell were they going to straighten these walls? I wondered.

Taylor and Curtis had also eaten through their projected timeline and still had to try to straighten the walls. After four days the walls were not even stacked, let alone straight and ready for concrete. Over another three days, all they did was straighten and adjust the walls. Using large bracing and strapping to make them level, straight and even. When Taylor finally told me they would be pouring concrete the next day, I had to run over and make sure.

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Praise Jebus! (This whole process is making me become very religious it seems.)

The following day the pumper truck was out, pumping a buttload of concrete into the basement walls. Now was the real test of the untested Nudura One walls and the Macgyver skills of the build team.

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I was nervous that day at work, just waiting for the phone call from Taylor explaining that there had been a catastrophic failure when the walls of the forms burst under the pressure of the concrete causing the walls to break apart and concrete to fill our basement.

But that call didn’t come. Relieved, we drove home at the end of the day. The walls were still standing and they were filled to the brim with concrete!

The next day we would pull the plywood off and see what magic laid beneath.

PS. Nudura has offered to cover at least some of the extra time of the build team for Research and Development of the Nudura One series.

High Performance Windows

One of the things I am most excited about in our house are the windows. We have a lot of windows in the house, 25 to be exact. And they are not terribly small. Even before knowing anything about energy efficient building, I’d always loved homes with large expansive windows overlooking a beautiful view. However, when building an extremely energy efficient home, the placement, size, glazing, window to floor ratio, and type of window matter a lot.

First, and perhaps most important, is which direction your windows should face. Obviously in the northern hemisphere, the sun is in the south. Therefore, the majority of your windows should face south and be able to take in the sunlight through the winter months when the sun is lower in the sky to provide some passive heating. Conveniently the sun is higher in the sky in the summer, so as long as you have properly sized overhangs or shading in the summer then you can prevent overheating. Recently we were in a neighbour’s house that was not designed with energy efficiency in mind. They have large south windows that are completely exposed, as well as some larger east and west facing. Even though they would (theoretically) have a great view, they had the interior blinds drawn on almost all of the windows!  Interior blinds and shades do very little to prevent overheating as the light/heat has already entered the space and will simply heat the blinds and radiate inside anyway.

For us, we maximized our southern exposure (but not too much as you can still overheat in the winter – even at minus 40° Celsius). And minimized our northern, eastern and western windows. Fortunately for us our best view is to the south and east. We do have a couple large windows on the east side of the house to take advantage of the river valley and our unobstructed view of the sunrise (to not put windows there would be foolish). We would have liked to have put more windows on the east, but in order to do so that would require shutters on the exterior, thus obstructing the view anyway. Shutters are really the only way to “shade” light from the east and west as the sun is too low in the sky throughout the year (at sunrise and sunset) to actually “shade” it. As for the north we don’t have much of a view, and so only have two windows. One in a bedroom for ventilation and fire safety and the other in the hall for ventilation. Northern windows really don’t provide any benefit in energy efficiency and are actually an energy penalty.

As for glazings, these are really amazing and can help with heat gain or blocking unwanted heat.The glazing does not at all block the view. I think of it like sunscreen. On the east and west windows, you want more sunscreen because you don’t want to overheat. On the south you want minimal sunscreen because you want that good passive heating in the winter (as long as you account for passive shading in the summer).

Ok so what type of windows do you buy? Wood, PVC or fiberglass? We had really hoped that we would be able to afford fiberglass windows. These are simply the best for energy efficiency, durability and quality. The frames themselves are made of 60% glass (fiber-glass) and so they move with the expansion and contraction from the heat and cold of the windows. Consider -40°Celsius outside and +20°Celsius inside. That is a 60° change that occurs through about a one inch space. PVC and wood will flex and bend at a different rate then the glass, leading to more air leakage, reduced air seal, and eventual failure of the window over time. Fiberglass however does not have the same issues. Duxton Windows has some excellent information on their website.

Duxton fiberglass windows

Now that we had an idea of what we wanted, we needed to determine which supplier to go with. We priced out Duxton (fiberglass), Accurate Dorwin (fiberglass) and Plygem (PVC/wood). We did not consider any of the crazy German imported windows. Shockingly, people actually do this (this is where the economics of Passive House and extreme energy efficiency clash with reality and sustainability, as I’ve written about before). I was actually talking to a house designer the other day who was raving about some German windows they’d started to import. Indeed they are impressive windows – but they are coming from fricking Germany! My thought when building a “sustainable” home is that we should be really considering if we are spending our money wisely or if it could have a better effect elsewhere (for example, spending $15,000 more on windows to get a marginal energy improvement versus $15,000 in solar panels). AND if you are importing your high performance windows from 4000 miles away and shipping them on a cargo ship across the ocean… well… is that sustainable?!

Anyways, I knew that the fiberglass windows would be more expensive than wood/PVC – but how much more was the question? When we received the quotes back I was pleased to see that the fiberglass windows came in only 20% more expensive then PVC. For the added efficiency, durability, warranty and, not to mention the larger viewing area of the window (fiberglass is stronger therefore can have a smaller frame and more glass) it was a no-brainer to go with fiberglass. We ended up choosing Duxton over Accurate Dorwin due simply to the fact that our designer had recommended them. The price difference between the two companies was marginal.

Via duxtonwindows.com

In designing the house and choosing the windows I tend to think about what Christopher Alexander of the Pattern Language says: “light on two sides of every room.” I loved reading this book because it was all about aesthetics. Written in the 1960s, it did not give a crap about energy efficiency. It was a nice reality check against all of the energy efficient dogma that in some cases can really get out of control. You still need a home that you actually want to spend time in.

Pattern Language by Christopher Alexander

Final planning

We have spent the past 9 months exhaustively planning this house and finally the light at the end of the tunnel is almost here. The design is done, the quotes have been tendered and received, the design fees have been paid (almost), the development permit approved, and we are just waiting on the appraisal from the bank and stamped drawings from the engineer. Initially the planning process was fun, but about three months ago we had pretty much had enough of it.And now, well, we have definitely had enough of it.

I keep thinking to myself “haven’t we talked about this house long enough??” But there are so many important little details that go into the planning and building of a house. I may have had a small idea of this before, but really this whole process shines a completely different light on the importance of Planning. When moving into and renovating an old house, you learn to live with and work with the idiosyncrasies and nuances of an old house (nothing being level, that weird door, baseboards not quite lining up, that one awkward window that looks onto nothing, and so on), but when building a house, you really don’t want to start off with any of those weird things. I am very detail oriented and like to research things to the n-th degree, much the chagrin of my wife from time to time – except in this process. My anal-retentiveness has finally come in handy!

If you are planning to build a house, and are not detail oriented then you need to learn to be one. Otherwise you are liable to get a home that may be close to what you had asked for but not entirely what you had expected. I cannot tell you how many little mishaps, potential mistake, errors and omissions we have already caught and corrected. It is crazy to me at times, but really there are so many aspects that even the people you are paying to know about all of it may miss some of these details or do it the way they always have done it (even if you specifically say you want something else). So it’s all on you. You’re the only one there to make sure that it is done how you actually want it. Which means you have to research and know enough to at least ask the questions that will lead to ensuring that you will get what you want.

I have learned now to tell our team that when we want something, I ask to confirm that it was done, and then follow-up to make sure. I’m certain that the various people working on the house will be completely sick of me pestering them by the end, but I don’t care. I want to make sure that our house turns out as we have intended it to.

And if there is something that I don’t know about then I ask someone who does know to check it. And then double-check it and then triple-check it. Incredibly, on triple-checks we have still caught errors.

In the end, all of this stuff is just on paper. We actually haven’t even done anything yet. So we will see what the actual build process goes like. I’m hoping (wishful thinking perhaps) that because of the significant focus on the details in the planning stages that maybe, just maybe, the build process will go smooth. But this hope is not going to allow me to assume anything. At all. Ever. IMG_2699