Choosing Best Airtight Options in Japan

 

What kind of materials are available in Japan, where are they found, are they safe, how are they installed….?

 

If you are looking to design, build or own a comfortable healthy house that consumes minimal amounts of energy then you may have searched and come across the following basic formula (no rocket science involved):

 

1.     Airtight  

2.     Well insulated 

3.     Thermal bridge free (minimal heat/cooling energy loss at vulnerable spots in assembly)

4.     Proper solar orientation (sun in winter/shade in summer)

5.     Air ventilated (i.e., controlled fresh air!)

 

Of course, correct and healthy doses of above (Passivhaus Consultants can help with this) cannot be achieved without the expertise of engineers, architects and builders or without the proper materials. 

 

Ok, onto the topic of choosing the best airtight products (1 above) in Japan. First, let me start by showing an image of the effect on moisture infiltration of even a small (25mm or 1") hole in the airtight layer:

Thirty litres a year is a lot of moisture from one little hole (untaped seams, punctures from staples not covered up etc.)! It doesn't take much to imagine how this adds up and what the average home lets in these days-despite being more airtight than before. What does this cause: Mold, structural deterioration, and drafts which are not comfortable, conducive to build longevity, healthy, or energy efficient; adequate and proper installation is paramount.

Next let's outline how these products should look in relation to a growing energy/carbon footprint (reduction) conscious global society along with changing building codes ( e.g., BC Step Code (Canada) around the world:

 

They should be VOC free, have a low carbon footprint, superior sticking properties (where applicable) in weather extremes, be robust during rigors of construction, smarter (with regards to permeability in different directions), and have reputable certification that shows they meet above conditions. Simply put ones that are healthy and do a great job at keeping the energy and moisture where you want them. 

 

In my experience these sorts of products are difficult to find in Japan. For example, I recently did a search in Japan for foundation sealing tapes.

 

The first step was checking Japanese distributor sites based on known products readily available in Canadian, US, UK, and European markets-where Passivhaus is well established. What I found was 3M 8067 which hits a couple of the targets but not all. Beyond that not much else besides standard ¥500 rolls on the big sites and same at local distributor’s shop. So, what about health, comfort, product longevity and energy reduction (aka lower energy bill!) tapes? 

 

Well for products that deliver on the above I have turned my attention to one producer, Siga Swiss, for an upcoming Passive House project in Hokkaido. Why? Because they hit all of the above targets and more. The additional parts: Siga Swiss offers customizable solutions, transparent product info, computer simulated evaluations of your project (followed by recommendations) and provides training on best methods of application. They are committed to doing their part globally.

 

These are the kinds of products we need to be using on our projects in Japan to get ahead and help push the world out of the dinosaur climate age. To do this, when speaking with suppliers, architects, and engineers (you may be one yourself) ask whether a specific high performance product is available (like Siga Swiss for airtightness, etc.) in Japan. This will get conversations started and ideas flowing as well as help toward a better educated industry along with (yep again!) comfier, cheaper, and better built homes. Demand for better products can positively affect availability here in Japan. 

Of course, regarding any products that are pushing for similar goals already here in Japan please share and let’s discuss those too! Positive change works a lot better helping each other out. 

 

One final note-Alluding to traditional builds in a previous article on this site: “Yes we can!” (when we so chose traditional styles) keep these themes while blending with new building techniques, technologies and products (i.e., high performance airtight tapes and membranes) that make homes hit higher targets. Targets that are actually on their way to “2050 goals” rather than just words.