We are finally getting closer to finding out what it is that I am trying to achieve in my re-build and why. As you have read, this has been a process that has been building since childhood (excuse the pun) for me and has taken many roads to get to where I am today. But it has been during the last 4+ years, as a home inspector, that I have finally started to focus on sustainable and durable dwellings in a more serious fashion. In my work, I am seeing first hand the results of buildings that are poor at shedding water or have high air leakage rates; I am seeing buildings with rot, mould, and high energy bills.
Unlike my attitude out of high school, where I felt all learning was behind me, I was now a sponge looking to expand my knowledge of all things related to making a durable and efficient building. And the more I learned, the more I realize I do not know. My training has become particularly focused on the building envelope (or building enclosure as it is properly known).
As I started pouring over internet articles and various industry seminars, I was learning how this one component, the building enclosure, was so entirely responsible for how a dwelling will perform long term. It dictates the size of the heating system, the life span of the structure, the indoor air quality, maintenance and utility costs, and the health and happiness of the occupants.
I became a member of the BC Building Envelope Council and started to regularly attend their monthly lunch-and-learn seminars. I also became a member of Thermal Energy Comfort Association and have been attending their monthly dinner seminars which has helped me tie in the design of a heating system back to the building enclosure.
I then made an excellent decision and leapfrogged my learning forward by enrolling in the BCIT Building Envelope Performance course taught by Graham Finch of RDH (whom I consider to be one of the best building envelope gurus out there). Between Graham’s scientific brilliance and James Bourget’s (also of RDH and Graham’s assistant in class) ‘ya but, this is how we do it in the real world”, I was finally able to connect all the dots (OK, at least most of them) and make sense of the information I had been amassing for the last 25 years.
Make sure the envelope is right and the rest will take care of itself.
This course reinforced that it was the introduction and advancement of insulation and NOT too much air-tightness that has led to many of the problems plaguing our dwellings today. In class we were reminded that because air leakage is still occurring at a high rate in most structures built even today, and because the sheathing in the wall (or roof) assembly is now so much colder than it was in yesteryear, due to the ever increasing levels of insulation, we have created the perfect storm. We have built in large cold condensing plates within the wall assembly (the exterior wall sheathing) and regularly introduce warm moist interior air into these assemblies by means of air leakage. And we are surprised that the wall and roof assemblies fail? Have you ever taken an ice-cold can of Coke and put in on the table? What forms on the outside surface of the can? Is the can leaking? Of course not, the surface of the can is below the dew-point temperature of the air inside the room and so the moisture has now condensed into a liquid on the side of the can.
And then to add insult to injury, we still have the fact that we ignore that it rains in the Lower Mainland and have done very little until recently to keep bulk water out of our wall assemblies.
Soapbox On.
To all the architects out there, DESIGN YOUR BUILDING WITH OVERHANGS!!! To all the Municipalities out there, DON’T PENALIZE ARCHITECTS THAT DESIGN THEIR BUILDINGS WITH OVERHANGS!!!
Soapbox off.
I also started attending the Home Protection Office seminars, prepared and presented by Murray Frank (a passionate and very knowledgeable builder and educator who is always entertaining – hint, turn off your cell phone in his seminar or you owe him a beer!). Murray starting showing us a grand new way to build; a method that was energy-efficient, durable, and straightforward to build. This new building method focused on increasing thermal resistance to heat loss while at the same time concentrating on reducing dew point potentials within the wall cavities. This building method is, of course, exterior-insulated wall assemblies.
By placing the insulation outboard of the structural sheathing (or at least the vast majority), you allow the inboard face of the sheathing to remain at a consistent temperature with the interior of the dwelling, which then reduces the condensation potential. You are also then able to place it in a way that reduces thermal bridging because you do not have a stick-frame interrupting the insulation every 16”. This type of wall construction is prevalent in commercial and some multi-family dwellings but has never quite caught on in single-family dwellings. But as the code was now going to require even higher levels of insulation in our dwelling assemblies, we were reaching a critical mass where if we continued to build by stuffing an ever-widening stick frame with pink batts, we were going to make it almost impossible to build a wall assembly that would not suffer from moisture-related issues.
I then enrolled in the week-long Canadian Passive House course which was another excellent course and my first official introduction to ‘Green Building’. Passive House, or more appropriately Passivhaus, is a building method that concentrates ALL of its efforts on the Building Enclosure. No ‘Green Washing', just a bullet-proof and air-tight building envelope. In order to be certified, the energy requirements must be lowered to a tenth of what is built in North America today. How would you like heating and electrical bills that are 10% of what you pay today? I know I would. The program achieves this by building very thick wall, floor, and roof assemblies with a large volume of insulation installed to prevent thermal bridging (can you say continuous insulation), and then installing very highly performing windows of the proper size and placement based on the elevation of the dwelling, in order to welcome free heat from the sun when we want it and to block it when we don’t (lots of windows on the South, fewer on the East, even fewer on the West and very few on the North). This strategy is then complemented by a well designed ventilation system to provide the required air exchange for the occupants. These 3 steps form the majority of the program.
The program has met with much resistance and even at times ridicule in North America. Everyone laughs at the statement that these homes can be heated with a candle. But I do know first hand, that of all the programs I have studied (more on a later blog), this is the only program that puts the building envelope in the forefront of the program and achieves significant (90%) reductions in energy use and greenhouse gas production.
Does the program go too far? Many people that I respect say it does, and part of this journey for me is to determine and decide for myself if it does, and to what extent I may achieve a middle ground.
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