Sunday, 22 November 2015

Zero Waste

A walk down Bea Johnson's Path to Sustainable Living.

Life Without A Trashcan: A Look Inside the Zero Waste Home

One year of smart and sustainable living had some pretty, uh, jarring effects.

Bea has managed to reduce her family's garbage YEARLY output to the mason jar.  She does this by generally buying in bulk and using her own glass or cloth containers.

This is truly impressive and a example to try and follow.  While I have reduced the waste, that goes to landfills, in my home to about 2-3 garbage bags a year, I do end up with a LOT of packaging that must be recycled each week.  I will buy her book and try to start incorporating some of her ideas in my lifestyle going forward.

Friday, 30 October 2015

We need new testing procedures for insulation to show the full story.

Hey folks, Sorry it has been so long since last posting. Been busy on the house construction. I do keep a project journal and update it weekly at theEnclosure or you can click on the updates listed on the right side of this blog.

I should have a technical update for you soon where I review all of the products/methods I used in constructing my basement.  In the mean time, I wanted to expose my readers to an excellent article written by Rockford Boyer of Roxul.  In it, he identifies the risks of using a set insulation R-Value in your modelling as with many products, the resistance to heat loss changes depending on temperature.

 The Theory of R-value Relativity: The impact of thermal conductivity on building enclosure durability

 By Rockford Boyer, B. Arch. Sc., BSSOWhen designers are deciding which insulation products to specify for a given project, two questions come to mind: ‘What is the R-value?’ and ‘What is the permeance?’

 One of the things that caught my eye was the danger faced, when modelling in WUFI, of getting erroneous results.   I have extracted two of the tables and shown below.  As you can see, there is a huge difference between the reported results.  Fig 1 is using the material  from the WUFI database and Fig 2 is re-running the material with a material properties entered manually and based on actual testing.  The risk if you are not aware of these issues, is designing an assembly that in real life will act nothing like your model.  If you are lucky it will be better than the model but in most cases it will mean you have a higher risk in your assembly than designed for.  A risk that may overwhelm the assemblies ability to recover.

Fig. 1 Extrapolated R-Value based on WUFI material database.

Fig.2 Extrapolated R-Value based on actual lab testing

Monday, 31 August 2015

Insulating a Durisol ICF Foundation

Hey folks, sorry for the time span since the last post.  I have been concentrating on keeping my building journal up to date.

As I recently have had some free time due to yet another set of medical setbacks, I recently finished editing and uploading a video showing my process of adhering the Roxul ComfortBoardIS mineral wool insulation to my ICF foundation.

The Soprema Colphene Torch'N Stick membrane would typically be used on a site formed concrete foundation, but because I am using a ICF product from Durisol (made from mineralized wood fibre and cement slurry), I too could use this torch on membrane (a process that would destroy conventional EPS foam ICF forms).  The 'tacking' of the insulation to the membrane is only a light mechanical bond and is only suitable for a temporary support of the insulation (or dimple board and other protection sheets) until the backfill takes place.  You would not be able to use the method for a permanent attachment in an above grade assembly.

Once the insulation was attached, I then fastened dimple sheet to the insulation, installed a granular drainage plain, geotextile, and then compacted backfill.  You can read about these steps on my "coming out of the hole" journal entry.

The overall foundation assembly will have multiple layers of safety and will be very durable, but the installation is costly and very time consuming. I can understand why many of these steps are not incorporated into most residential construction. But then, most residential below grade basements are wet to some degree. As my friend Murray Frank often says "You never hear a comment 'It smells as good as a basement'".

Thanks for visiting folks. I will hopefully post a review of all the products I have used to create my foundation walls within the next few weeks. A majority of the products get a thumbs up from a technical standpoint, but one in particular is a two thumbs down with extreme prejudice.  I encourage you to subscribe if you want to be notified of when this review is posted.

Friday, 29 May 2015

Air Leakage of Old House - Does it matter?

*** Update - Upon further reflection of this topic, I do feel there is one additional reason to perform energy upgrades and discuss it in my project journal ***
This blog entry will analyze the air leakage of a 1954 house and relate that to the energy use and durability of the house.

Before I started tearing down my 1954 single storey 1500 sq ft bungalow to make way for, I decided to have the house tested for air leakage by Michael and Deborah from H&H small home solutions inc (hhsss at shaw dot ca).  H&H typically perform leakage testing to determine the EnerGuide rating for new construction, so this was going to be a new experience for them (and their blower door).

They came by in late March of 2014 after I had moved out but before I had completely emptied the house and before any deconstruction had been performed. The house was prepped by sealing the wood burning fireplace insert, range hood, and the through-wall mailbox before setting up the blower door.

We first ran the door in a B configuration and were unable to get up to the final test pressure of -50 Pa. But even in this configuration we got some scary results.  I had not really made any great attempts to air seal this house over the years.  There was weather stripping on 1 of the 3 doors, and the cedar siding had each coarse sealed to the next and the siding sealed to most of the window and door frames. But no attempts had been made to seal the interior interface with the attic plane and 1 of the doors had a cat door in it and the main door itself had very large gaps around it.

Prior to starting the test I had predicted an air leakage around 8-10 ACH (Air Changes per hour) @ -50 Pa, but early in the test we could tell it was going to be well above this. Deborah could tell just from the sound the fan was making (there previous worst house they tested was 11 ACH @ -50 Pa which was scary as it was new construction).

Right off the bat we reached 28 air exchanges at only -15 Pa!  To give you an idea, 15 Pa relates to a wind speed of only 11 MPH.  In the fall, I regularly recorded winds speeds on the property at this speed or higher so during those events all of that CONDITIONED air in the house was potentially changing over 28 times every hour. That is a lot of extra load on the heating plant and also explained the drafts my wife typically was feeling.

Over the next hour or so we tested at various configurations until we ran the fan at full open configuration (no restrictor plates). Only then could we get enough air volume to allow us to reach the target test pressure of -50 Pa.  AT the full test pressure we recorded an air leakage of 21.74 ACH -50Pa.

Now wait, some of you may have noticed that that is less air leakage than what we observed at only -15 Pa.  How is this possible you say?

Well, it is actually quite common.  As more and more negative pressure is placed on a dwelling, the two surfaces on each side of an air path (leak) can start to come together.  Eventually they can close up tight and stop that leak.  This why I have a bit of an issue (actually quite a bit), of testing dwellings at -50 Pa.  This relates to a wind speed of 20 Mph which is much higher than some locations would experience on a regular basis and much lower than other locations average wind speeds.  As such, it is my opinion that their should be a standard test pressure PER geographical region.  This could be a table much like the climate zone charts, but would be based on the average yearly mean wind speeds for a specific area.  Homes in higher wind speed regions should be tested at higher pressures than homes in lower wind speed regions.

(Side bar - the reason the wind speed is important is that it is this force that will effect the pressures on a dwelling.  Yes a house can depressurize under mechanical ventilation, but these are usually infrequent where wind depressurization or pressurization of the dwelling could occur for months at a time in windy locations).

So - these tests showed that the house was VERY leaky.  What does that mean in terms of heating bills, comfort, and building durability.

Heating Bills

The truth is, this air leakage did not really make a huge difference in energy costs.  My heating bills (for space and domestic hot water) were typically well under $2000 a year (We are under $2000 for both gas AND electrical use).  As I am a heavy bath user, it is safe to say aprox 40% of this was domestic hot water use.  This leaves an estimated $1000 in annual space heating costs.  That works out to less than $100 a month, or well less than the cost of a weekend dinner out.

We typically had the heat set for 72-73F in the wintertime and basically did not tough the thermostat all year.  It was not uncommon for the heat to come on during cold late spring and early fall evenings.  We did however use a programmable thermostat that was set to come on at 7 AM, step down to about 65F at 8:30 AM, come back to temp at 4 PM, and step back down to about 68F at 11:30 PM.  This was only partially for energy savings.  The night time set backs were used because we had hydronic heating through large built-in wall registers (1-2 per room) via a 1980's gas boiler.  The pipes went through and rubbed on the wood sub-floor assembly, so if the heat came on during the night the 'clicking' would wake me up.  So we partially closed the bedroom door (so cats could still get in and out and not cause another source of nighttime wake-ups) and used an electric oil heater to maintain a comfortable temp in the bedroom.

While air tightness is important, it will not make a huge difference to your pocket book unless you have a very large and leaky house.


The air leakage did however make a big difference in occupant comfort and should, in my opinion, be the biggest (and probably only) reason to upgrade an older home.  The house was uncomfortable to sit in near any exterior wall in the winter months due to the drafts present.  I was quite surprised when I saw how leaky the fixed, but home made, windows in the living room were.  The builder had just placed the single pane of window glass against a wood surface and clamped it with a second wood component.  At -15Pa, the wind just whistled through these locations.  There is no question, that making the house more air tight would have made the house more comfortable.


Normally when one discusses the reasons for making a dwelling air tight, it is in the context of a 'modern' home with current levels of code required insulation.  With modern levels of insulation, it is critical to ensure that air leakage does not occur, in order to prevent interior air leaking into the wall or roof assembly and condensing on cold sheathing.  Left unchecked, this will often lead to mold and rot within the assembly.

The key here is the qty and location of the insulation.  As soon as enough insulation is placed inside of the sheathing to allow the sheathing to cool down below the dew point of the interior air, you now have an assembly with a very high liability should any appreciable amount of air leak into that assembly from the conditioned interior. This is because air currents are the #1 mover of moisture next to bulk water leaks caused by plumbing leaks or incorrectly detailed cladding or roofs that permit bulk rain water entry into the assembly.

But in older houses like the one I took down (which had ZERO insulation in the walls), there is not enough insulation present to block the heat loss from the house enough to allow the sheathing to get to the dangerous dew point conditions.  If you never reach the dew point, you can have huge amounts of moisture moving into the wall via air leakage and never have to worry about it because it stays in vapour form and just moves on through either to the outside of the dwelling or back into the inside. There is never liquid water that results from this air leakage. This is the reason why older homes have performed so well over many decades without the presence of air barriers, vapour barriers, or even effective water shedding surfaces.  The heat loss has always been enough to 'cook' any accumulated moisture out of the assembly.


We have identified in this article that there is not a huge financial penalty for a leaky house.  In my case, the costs per month for space heating were under $100/month in what is considered a cold-heating-dominated climate.  This $1200 annual investment would not get very far in paying for a deep energy retrofit which typically would cost 10's of thousands of dollars.  Lets say you could reduce the heating load even as much as 75% (purely speculative and most likely could not meet), this would represent $900 annual contribution to renovation costs.

A REALLY cheap stud level renovation for my home (including new windows and doors) would have been at least $60K (going to need to rip out parts of bathrooms and kitchens so most likely will totally renovate those rooms - my budget of $60 assumes very low end cabinets for these rooms).

A very intensive attic floor plane sealing regime would have been at least $15K (not going to do this process without bringing attic up to current insulation levels when done).

At a highly inflated $900 annual savings, these two projects would have a 66 and 17 year payback respectively. The attic plane sealing payback would most likely be much longer as only sealing this plane would probably represent only 50-70% of all air leakage present and therefore there would be reduced energy savings.

And my house did not represent an unusual annual energy bill. This US Energy Summary shows that for the West, the average annual winter heating bill per household varies between $1300 and $800 depending on year.

In the end, due to our really low energy costs, and the likely hood that they will not appreciably escalate for many decades due to Government interference, it makes very little sense to upgrade an existing homes energy performance for personal financial savings.  Therefore the type of renovation needed to reduce air leakage or increase thermal performance, only makes sense if the home is being renovated anyway for cosmetic or occupant comfort reasons.

On a separate track - this logic also holds true when analyzing extreme new construction programs like Passive House.  The costs to reach passive house levels of energy reduction will not be paid back over the lifespan of the dwelling in most cases. The added detriment of these programs is that the embodied energy of the insulation products built into these dwellings also do not have a pay back within the lifespan of the dwelling.  Instead for new construction, it makes more sense to build a "Pretty Good House" (coined by Joe Lstiburek) and then use the excess capital available to either contribute to distributed or on-site energy generation.

It is however critical that air leakage be reduced down to a minimum (experts do not agree how little is adequate - but the number is somewhere between 1ACH+/-50 and 3ACH+/-50) for new construction or energy retrofits IF, you have built an assembly with enough insulation inboard of the sheathing to cause the sheathing to cool down to the dew point potential of any leaking interior air.   If you build a safer assembly with the insulation outboard of the sheathing (or enough outboard to maintain the sheathing above the dew point potential), then while air leakage is still important to address from an energy loss standpoint (the costs to get it right during construction are minimal and will be paid back by reduced energy usage), it usually will not cause a durability concern for the assembly.  This of course is all from the perspective of a heating dominated climate.  The direction of flow and order of layers for the assembly are different in a cooling dominated or mixed climate.

Sunday, 5 April 2015

Foundation Rebar Installation Primer

Wow - cannot believe it was last November when I last posted to this blog!  I promise to start writing more technical posting (as opposed to the daily journal entries found at my building web site).

I posted this on my journal as well, but felt it was important enough to also post here.

I received some feedback to my journal posting yesterday that was suggesting I should look at the 'other' ICF manufacturers if I wanted to know how Rebar was 'supposed' to be placed.  I did and the result sure is scary.  Because you are allowed to install ICF walls without ANY engineering assistance (as long as you meet the building codes requirements including max unsupported wall height) and therefore engineering inspection, there is a plethora of miss-information out there regarding the requirements for rebar reinforcing of an ICF wall.

At least the BC Building code makes it pretty clear on the requirements, but I suspect that because the Municipal inspector is not present at time of pour, these requirements may not be adhered to - at least that is what is evidenced by one of the discussion forums I visited last night.

So - lets first look at the BC Building Code requirements.

The Horizontal rods are to be installed every 2 ft vertically and are to have 1-3/16" inside minimum cover (30mm) meaning that the rod is to be held off the outboard surface of the inside ICF panel to allow 1-3/16" of concrete to be present on the inside face of the bar.

The Vertical rods are to be installed per tables BCBC A to C depending on core thickness and height of wall.  The first options calls for vertical rod placed every 16" horizontally with again 1-3/16" inside cover (30mm) minimum.

Obviously both vertical and horizontal bars are unable to occupy the same plane off the inside face of the foundation, so the code also specifies a max cover by stating the bars are to be "located located in the inside half of the wall section".

My requirements were much more stringent because of the height of the wall.  The engineer specified vertical bars every 12" horizontally and horizontal bars every 2' vertically.  I was not given a range for the vertical bar - it required 1.5" of inside cover.  When I asked if 2" or even 2.5" would be OK, I was informed that they would have to rerun all of the calculations and that they suspected there would be problems.  So, I did by best to ensure 1.5" cover.

My drawings also specified 1.5" cover for the horizontal bars, but I failed to abide by that when placing the bars.  Because I drew up the structural drawings (with the instructions received from the engineer), and had drawn the horizontal in the centre of the core, and because I am more of a visual person instead of word person - I placed the horizontal bar down the middle of the blocks during installation.  Fortunately, my blunder was forgiven.  When doing the calculations for the wall, the engineer had generally only used the vertical bars in the strength calculations and the horizontal bars were more present for crack control. I was very relieved (and thank-full to Tacoma for providing very fast responses to all of my rebar questions), as by the time I had discovered the blunder, all of the horizontal bar had already been placed.  While waiting for the reply to come the following morning, I tossed and turned all night worrying I was going to have to disassemble the wall or pay for a fibre additive to add to the concrete for strength, like the Helix fibre (you may remember from an earlier posting, I was looking at this but had ruled it out as being too costly considering it could not replace ALL of the vertical rods).

The most important point of this primer is that you MUST pay attention to the cover stated for each bar installation.  A bar placed without the appropriate cover almost becomes a bar that no longer contributes to the strength of the wall. For instance, if the bar was placed on the outside half of the core, you may as well not even have it there.  This brings me to the next part of my primer.

Rebar chair is used to hold rod at a precise cover off the inside face of the forms.
Why is rebar installed in concrete anyway? 

Concrete has awesome compression strength but is quite poor in tension. Because the weight of the back-filled soil is pressing on the foundation, it wants to  'bow' inward under the pressure.  This would place the outside half of the core into compression but would place the inside half under tension (just like a floor joist but in a vertical plane).  The inside half of the concrete core is trying to stretch to accommodate the bow.  As concrete is not good when pulled on, the stretching would eventually cause the concrete to fracture.  By placing rebar into the concrete, it prevents the concrete from stretching too far and fracturing.  The closer the bar is to the inside face of the concrete core, the more tension forces it will encounter.  Another way to look at this is the distance it would take to run or drive around the outside of a track compared to the inside lane of a track.  The further outboard you get, the farther you run or the longer the circuit is.

So, if your wall is designed with 1.5" inside cover, that means the engineer has calculated the stresses of the wall at that 1.5" plane and ensured to call out a rebar pattern that can accommodate those stresses. If there is not enough cover, then there will not be enough concrete to properly capture the bar and keep it in place, but if there is too much cover the rebar will not be able to remove enough of the load from the 'stretch' of the wall and the concrete will fracture. If the rebar was placed in the outside half of the core, it would no longer be subjected to ANY tension and in fact would be being squeezed by the surrounding concrete that is under compression forces.

While researching this last night I came across the installation instructions for a very popular rigid foam based ICF (and the manufacturer that was reportedly sued in the West Vancouver failure).  They instruct the installer to "Place plastic sleeves (1½" [38mm] conduit) over stub steel for later placement of vertical steel" meaning to slip chunks of plastic conduit over the dowels placed in the footing to later capture the bottom end of the vertical rod.  But as the dowels are placed typically down the centre of the footing, this would place the vertical rods down the neutral plane of the foundation wall, or a spot it will do very little good to resist the tensions of the foundation wall.

I also came across this forum on discussing the placement of the steel and it was very clear a majority of the contributors did not truly 'get it'. Lets quickly correct some of the miss-information.  
  • Why do we tie off rebar under some circumstances?
Simply to hold the bar in the RIGHT position until the concrete has been poured and can hold the bar for us.  It provides NO structural strength whatsoever. 

So why is the tying off of the rebar inspected before pouring by the engineers? Why is it important that the tie-off securely fastens the bars together?  Because as we have discussed above, it is critical that the bar is placed in the right position to ensure it can bare the intended load.  As the tie wire is quite brittle, if the bars can move slightly because of not being tied-off tightly, there is a chance the sudden shock of the movement could break the wire which would now allow for the bar to move substantially out of position.
  • Is it important that the horizontal bars are tied to the vertical bars (something that cannot be done in ICF construction)? 
No - full stop.  Each orientation of the bar is typically handling separately calculated loads and not considered an 'assembly' (In some extreme cases I do believe it is a 'grid' that is designed, but in these cases sophisticated FEA software is used and the bar must be welded together not tied).
  • Is staggering the horizontal bars to capture the vertical bar the required solution?
No - this is only appropriate for above grade ICF installations.  In order to ensure the vertical bar was placed inboard enough on the core, the inside horizontal bar would not have enough cover.
  • Why is it important to tie-off splices?
You need to ensure that the bars are fully encased in concrete.  If the bars were not tied tight to each other, they would allow small pockets to form between the bars that were too small for the flow of concrete.  This would provide a weak point because the bar would now not be in communication with the concrete and therefore unable to bare the intended load.  This is why bars in close proximity, and in the same plane, need to be tightly bundled or held apart a minimum distance by means of chairs or other securing.
  • Why do the vertical bars not need to be tied-off or otherwise captured to the footing dowels?
Footing dowels or any other dowels have nothing to do with the tension stresses a concrete  assembly is under.  Their sole purpose is to tie the concrete on each side of a cold seam (concrete poured at two different occasions) together.  SO in the case of a footing dowel, the purpose is to ensure the foundation wall cannot 'slip off (shear)' of the footing.  This is why most codes also allow the formation of a key in the footing, instead of the dowels, to capture the bottom side of the foundation.

Hope this has been of some assistance. Should there be something that you disagree with, then please provide documented background for your disagreement and I will reconsider.

Thanks for visiting.