Construction Commenced - Countdown to occupancy

Wednesday, 15 October 2014

Does PassiveHaus make sense?

Just a short update to showcase an article at Green Building Adviser that perfectly sums up the conclusions I made about the Passive House program and why I cancelled my plans to build to that standard.

The author of the article, found at www.greenbuildingadvisor.com/blogs/dept/musings/it-s-not-about-space-heating, tracked the actual energy use of several homes in Massachusetts and has determined that even a modest investment in insulation and air tightness (termed a pretty good house by Joe Lstiburek) is more than enough to reduce the heating and cooling loads to the point where it makes more sense to concentrate on plug and domestic hot water loads as is shown in the below graphic.


Extracted from http://www.greenbuildingadvisor.com/sites/default/files/images/Rosenbaum%20-%20Graph%20of%20Eliakims%20Way%20data%20copy.preview.jpg

The real world data monitoring has also shown that the assumptions made in the PHPP (the modelling system for PassiveHaus) are often wrong.  The author states, “PHPP assumes 6.6 gallons [25 liters] of hot water a day per person, but that’s not enough for normal Americans.”

I jumped on board the PassiveHaus train for about a year in the early design stages of my upcoming build.  It was easy to be swept up in the well polished program and fall in love with the projected savings.  But as I became better and better educated on building science, source energy, and embodied energy, I felt their were huge holes in the program.  The underlying principles of air tightness and thermal bridge free construction were sound, but in my view the chase for heating and cooling reductions bypassed the sweet spot where it made much more sense, from an embodied energy and a cost point of view, to look at on site production than further reduction. The biggest stumbling block was the claimed 10-15% added build cost to reach PH when in reality it is much closer to 200% on average when comparing to a code min house (which after all is what the majority of homes in North America are built to).

In the end I decided to build a "pretty good house" and will monitor energy loads once occupied and then model whether or not I reached the sweet spot between reduction and production.

Thanks for visiting.  For the current status of the build please visit http://www.theenclosure.ca/project-journal/

PS: For an excellent article on why  more insulation is not always better, read http://www.greenbuildingadvisor.com/blogs/dept/building-science/diminishing-returns-adding-insulation

Sunday, 31 August 2014

Sub Slab Insulation - EPS vs XPS

As some of my regular readers know, I tested samples of EPS and XPS in an underground wet environment to see which over time absorbed more moisture.

I described the experiment design in my blog posting of Aug 22, 2013 and describe the start of the experiment in my posting of October 6, 2013.

Fig 1: Samples at beginning of experiment.  These were buried below aprox 4 ft of dirt in a wet environment subjected to regular/constant ground water.
 I dug up the samples March 25, 2014 and the results do not look good for EPS.



Table 1: Weight of buried samples at end of 9 months.
As you can see in table 1, over the same period of time and in the same conditions, EPS absorbed an average of 258% of its original mass in additional water compared to only 31% for XPS.

Once I finished my on-site testing of the samples, I then took them all down to Fitsum Tariku, an instructor at BCIT and Director of Building Science Centre of Excellence (to name just some of his many accomplishments and titles). Fitsum offered to have some of his Masters students in the Master of Engineering in Building Science program run some experiments to determine the total moisture take-up potential of both products as well as the thermal resistance once saturated.

Unfortunately they were unable to use my buried samples because they were too damaged (I should have bed them in a thicker layer of sand both below and above to protect the integrity of the samples - however it was still a very revealing test based on my results in table 1 above).  Instead they used samples I had submerged in a tub of water and others I had on a shelf during the experiment.

In the following tables, you can see that EPS also does poorly from a R-Value retention point of view when saturated compared to XPS.

Table 2: Dry weight of samples measured by BCIT
Table 3: Measured R-Value (using Hot Box) of both dry and wet samples
Table 4: Difference in R-Value between two insulation types both when dry and wet.
Table 5: Loss of thermal resistance when saturated.

The last graphic tells it all - EPS looses 15.7% of its thermal resistance when in a wet environment and saturated compared to only 3% for XPS.

So why is EPS used in many 'green' projects.  This stems from the EPS industries claims that it represents a lower Global Warming Potential vs XPS due to its use of Pentane as a blowing agent compared to the traditional HCFC agent used by the XPS industry.  But XPS manufacturers like Owens Corning have already replaced their blowing agent with a Zero Ozone Depleting formula.

Finally, one positive recorded result is that both products met or exceeded their published thermal resistance per inch of R4.27 for EPS and R5 for XPS (as shown in table 3 - dry state). 

The outcome in our view is pretty clear cut - over the extended period representing the lifespan of a dwelling (50+ Years), the lower initial thermal resistance, and then the significant deteriorating of R value if EPS gets wet and stays wet, far out-way any environmental benefits claimed for EPS.  The obvious choice for below slab insulation applications is clearly XPS when all factors are taken into consideration.

Sample Specifications:
XPS - Owens Corning Foamular C-300 (30 psi) 
EPS - Plasti-Fab PlastiSpan 30 (30 psi) 

Sunday, 10 August 2014

SENWiEco concludes testing of DURISOL ICF Block

When choosing a foundation your options are typically a site formed and poured concrete wall or some form of insulated concrete form (ICF) wall.  Early on in the process I gravitated to an ICF wall because it would eliminate the need to hire forming crews and rent and fabricate forms.

When looking at ICF, the traditional product is made from some form of EPS foam which has a very high embodied energy, lots of off-gassing, and is made from non-renewable components. The foam industry (EPS and XPS) will try to 'green-wash' this by stating the foam, as an insulation, reduces heat loss and reduces carbon output over the lifespan of the dwelling.  Yes this is true for ANY insulation, so choosing an insulation with a starting lower embodied energy will put you that much further ahead on your reduction goals. So again, early in the process I looked for a product that on the surface was friendlier to the planet.

One of the benefits of all ICF walls is that they typically require a smaller concrete core than a standard foundation.  The code allows for a 5.5" core on ICF walls where a standard site formed wall generally start at 8".  The reason for this escapes me because the ICF product itself is not considered structural so why would all walls not be allowed to be only 5.5" regardless of forming method.  If someone knows the answer to this please post a comment.  The smaller core of the ICF significantly reduces the concrete needed and therefore the cost and embodied energy of the overall wall.

One of the other downsides to a typical ICF forming material (foam), is that you end up with too much insulation on the inboard face of the core.  This decouples the core from the interior environment and can lead to condensation in some isolated cases, but more importantly it limits the walls ability to be a moderating force to the homes inside environment. An exposed concrete wall can buffer the temperatures by acting as a thermal mass.

The further downside to foam style ICF blocks is that just about everyone loves them from rats to ants.  They burrow and nest in the product creating holes in your thermal blanket.  They are also quite fragile and can be easily damaged during construction and require significant blocking during pouring to prevent blow-out.

My quest for the perfect block led me to the Durisol product.  It is made with virgin but scrap wood (manufacturing waste and tree tops).  This wood is chipped and then through a patented process, the organics are removed to create a mineralized wood fibre (think petrified wood).  This is then added to a cement slurry and formed into the ICF block.  This process and product would help meet my goals to dramatically reduce the embodied energy of the foundaiton.

There is another similar product made by Nudura, but my research indicated that this product utilized non-virgin wood sources like used pallets and had a lot more dimensional tolerance issues with the block itself.  I also was informed that Nudura was initially going to be a licensee of Durisol but ended up swiping the formulation and heading out n their own.  This did not sound like the right fit for me so I focused on Durisol even though it meant I would have to freight them from back east.

Once I decided to seriously consider Durisol, I then wanted to ensure it was suitable for the task. My immediate concern was that the blocks would rot.  But the product has been used for decades as sound abatement walls on highways (where some of the wall is always buried) and I received a letter from the Ontario Ministry of Transport advising that they have never had to repair a wall due to decay (just traffic accident damage).

My next concern was how would this wall act from the point of view of air and moisture movement.  It was made clear from the beginning, that I would need a independent air barrier as this product was air permeable (it has webs that penetrate through the concrete core so the core is not continuous).   So this was a negative against the product when compared to foam, but as I wanted a bullet proof building enclosure, I had always planned on an robust WRB (water resistant barrier) on the exterior of the foundation.  I think the idea of 'damp-proofing' a foundation wall in a rain forest climate is ludicrous and had always planned on Water Proofing my wall.  And a waterproof membrane is almost always also an air barrier.

My next concern was how the blocks would act if subjected to regular wetting.  The manufacturer claimed the product was unable to support capillary action and had some university testing to support.  But I was not satisfied and so set out to torture test the product over 16 months.  I started the experiment in Jan of 2013 (Begin experiment).  At the eight month mark I posted the status) Status at 8 months) and then altered the block to also contain the concrete core.  The experiment concluded on June 1, 2014.




All off my testing supported the manufactures claims.  This was a free draining assembly that did not support moisture movement from the outboard to inboard face.   I will also be preventing moisture movement through the footings via a FastFoot mebrane and also using a touch-on or self-adhered AB/WRB mebrane on the outside face of the foundation and so will have a very durable and forgiving assembly.  I now felt confident using this product on my project and have now received the product on site.  Once the excavation is complete, I will post some videos on the installation of the product (visit my project journal for the tribulations in getting these goods to site).

As I have time (may be at end of construction, I will also try to post some cost comparisons between the various options and the embodied energy numbers).

Thanks for visiting.







Thursday, 3 July 2014

Clothing Charities

I was going through my notes and thought I would post the charities I researched on the North Shore (Vancouver BC) that deal with woman's clothes in case it helps anyone else.  All have worthy clients they are assisting.

http://avalonrecoverysociety.org/

http://dressforsuccess.org/home.aspx
(Clothes must be cleaned and no receipt.  They do not take casual.)

http://www.harvestproject.org/programs/thrift-store-2/

http://nscss.net/

www.northshorewomen.ca

Cheers

Sunday, 15 June 2014

Missed Deadline - again!

Well as you can see by the web-cams, we are no where near ready to start the big dig.  So today's' deadline will come and go like many previous.

The deconstruction is now going pretty much to schedule, but we just did not start soon enough due to all the lost time re-engineering the structure to meet the new District policies. May was meant to be tear down month but both April and May were generally spent on re-engineering and drawing and getting the house fully empty.  This is one downside to doing ALL the work myself -  There is no overlap.  In general, I did not start this project prepared.  I had intended to purge and empty the house over the winter, but was generally fully occupied with drawing, redesign, and variance approvals.

I have pretty much given up on a schedule at this point and am just working as hard as I can each day to move forward. The actual deconstruction did not start until May 12 with the removal of the Kitchen followed shortly after by the laundry room.  We then had to prepare for the asbestos remediation. Since the remediation of the asbestos laden drywall completed June 4, I have been able to lift up aprox 650 sq. ft. of beech hardwood flooring (including grinding off nails), removed wood panelling from hallways,  removed all of the wood planking that was installed behind the panelling, and as of yesterday remove all of the non-bearing internal walls.

Front entrance at back left.   White wall used to be bathroom and back right was spare bedroom.  Wall in foreground is the central bearing wall holding up the ceiling joists.

Foreground was dinning room and stack of salvage 2x4.  Room behind brick chimney was laundry utilities and room to right was kitchen.  The few renaming posts are holding up some splicing in the ceiling joists near a roof valley above. Just visible behind chimney is a remaining bearing wall holding up ceiling joists at the south half of the house.
 Over the next week I hope to stack the salvaged wood outside (need to figure out where as really tight on space!), take a garbage and green waste run to the transfer station, pull up the sub-floors (this is plywood screwed to ship-lap, nailed to 2x4 sleepers. When we had the hardwood put in, I installed about 18 pounds of screws in the sub-floor to reduce the creaking that was present.  There is no way I will have the time to remove all of these screws to salvage any of the sub-flooring, so I will just be cutting it into 4ft x 4ft panels and taking to dump unfortunately), and then start taking off the exterior siding.  This should be much easier using the offset for the reciprocating saw I talked about on an earlier posting.

Lets see how well I do meeting this goal.

Thanks for stopping by!


Wednesday, 11 June 2014

Thermal Bridging - The New Buzz Word

Just a short message tonight.  I finally got around to reading the Winter 2013 Journal of Building Enclosure Design and it was chalk full of articles on the importance of preventing thermal bridging across balcony slabs.

This is a hot topic in most BE circles right now.  Even as little as 5 years ago, most energy models ignored the thermal bridging that results at this interface, but as I wrote a couple of days ago, even though the slab only represent around 3% of the total wall area, if not thermally broken, it can easily diminish the entire walls thermal resistance by 50% or more.

The construction industry and building designers are finally listening to the Building Scientists and realizing that details really do mater!  We need to start building smarter because there are too many Aqua Towers in this world.

Thanks for stopping by and please visit my project journal often as I am posting almost daily now.

Cheers!

Monday, 9 June 2014

RCI Conference

Sorry for the repeat to those that follow both my Blog and Journal, but this info was too good to miss.

Please visit http://www.theenclosure.ca/project-journal for the lunacy surrounding slab edge thermal bridging, double stud construction, and wrapping buildings in foam.

Thanks For Visiting!