Dan is actively sealing his house as well as getting past a few more milestones.  Most of the stairs are in, the ventilation system is being piped in and sealed.  Stu returned to make another appearance and Dan put him to work.  Dan has sealed the doorway between the workshop and the utility room with OSB and tape.  He installed a fan in the door and is using that to pressurize the house so he can go around and look for leaks.  He will be gluing and taping the areas he finds and another official blower door test will be run.  Dan has also promised a first hand report of his experience with the air tight sealing methods when he can get time to turn around twice.

A very interesting air leak showed up during the testing.  In the ADU Dan has installed wooden beams.  Because the structure changes at that point from the Larsen Trusses that had the structural support on the front cord to 2X walls with the support on the outside, the beams had to pass through the air tight layer of OSB.  Dan sealed around each beam, but when the building was pressurized he discovered that splits in the wood acted like an Air Super Highway.  He said you could just feel the wind racing through the cracks.  He plans to fill the cracks with putty and sand them down since the beams are going to be left exposed.  Stay tuned!  -Linda

I left you with quite a cliffhanger regarding Dan’s project and the blower door test.  I thought I would explain a bit about the Passive House concepts that are affecting the results.  Passive House projects are measured in a variety of ways. 

For determining the Annual Heat Demand, the Gross Enclosed Volume of the building is used – that is the area enclosed by the  extreme outside of the thermal envelope.  In this cross-section of one part of Dan’s project the Gross Enclosed Volume is represented by a dashed blue line.  The yellow represents the insulation in the walls and under the slab.  The red line is the OSB and top of the slab that create the air tight layer.

For Ventilation purposes, the Net enclosed Volume of the building is used.  This is where the question of the project passing the blower door test got a little sideways.  In America, pressurization tests use different volume measurements normally and a number equivalent to the volume enclosed by the air tight layer (including interior walls and floors) was calculated.

For Passive House purposes a more conservative number is to be used for the Net Enclosed Volume.  Basically  it is the empty area that is ventilated within the thermal envelope.  For this project that is all the blank space within the red air tight layer EXCEPT for the bright green area that makes up the floor and interior walls.  The argument can be made that these constructions are not built air tight and will become pressurized and ventilated, but Passive House measurements are conservative and these volumes are not included in the Net Enclosed Volume.

Dan will be crunching the numbers, air sealing some more with the wonderful tape that Siga sent for the project, and trying again to keep under the .6ACH @ 50 pascal requirement that certified Passive House projects must reach.  He is very determined to do so.  He allowed for this scenario when he planned the blower door test.  His air tight layer is still accessible and he does have the opportunity to go back and make changes easily.  When planning your Passive House project, make sure you plan ahead so that you too can tighten the air tight layer if necessary without a lot of fuss.

Dan has really done a remarkable job with his project and I for one am learning so much from following it and presenting it to you on this blog.  Thanks for following along!

-Linda

[updated to clarify interior wall and floor volume are not included in the Net Enclosed Volume.]

I love the concept of Existing Resources. Take what you have and preserve it or adapt it. Given enough thought a new life for an old something can create an even newer concept. In communications we have gone from word of mouth and town criers to the internet and bloggers. It’s still passing on ideas and news, just differently. In the world of building we have gone from building with new materials to restoring old places, to dismantling them to become something else. Now we are looking carefully at the cost that building has to the world at large and trying to make a sustainable change for the better and one way we share those ideas is visually through the internet.

For 234 years this country has been adapting and changing, examining what is important and searching to make a better way that benefits its citizens while considering its position in the world at large. It’s not always been easy since we declared our independence, but the one thing that we have relied on as a country is that our Constitution and its’ Bill of Rights has granted us rights that we hold dear.  The world can watch us debate and disagree and stand up for each others’ right to do so.  What an enduring resource our founding fathers left for us.  Happy Birthday USA!

The “Stars and Stripes Forever” march, written in 1896 by John Phillip Sousa is an Existing Resource that has been adapted to create a new visual concept to be presented on the internet.  The different instruments are represented by different colored lines and the length of the notes is represented by the length of the bars.  Enjoy!

[youtube=http://www.youtube.com/watch?v=cx0RRdPdKcM&hl=en_US&fs=1]

…but did Dan’s house reach 0.6ACH @ 50 pascal?  The answer is a resounding “maybe”.  Between needing a smaller cowl for the blower door (a temporary cardboard one was crafted) and a question of volume it was most likely between 0.5 and 0.7ACH & 50 pascal – definitely in the ballpark.

Dan was really impressed with the Siga tape – thank you Siga!  Albert Rooks of the Small Planet Workshop will be a US distributor for it in the future.

I will post an update with details as they are available.

Let’s have some fun in anticipation of the blower door test next week.  I for one am glad that Dan is pushing the envelope to find out just how much effort and what materials are needed on his project to achieve the Passive House air tight requirement.  I know that many people are following this blog and are interested in the construction techniques that he is using.  I would bet that more than a few wonder for themselves just how much attention to detail is necessary and, for cost and schedule considerations, what is not.

Just to recap, here is part of a comment Dan made recently on the post I made regarding the insulation that was blown in.  (I appreciate the additional information – thanks Dan!)  “When it comes to air-sealing, the approach is a bit of an experiment. Up to this point, I have been using both glue and building gaskets. I will be using tape in a number of locations. (I’m hopefully going to get to utilize some of the famed Siga tape.) When the fateful day of the Blower Door Test arrives (tentatively scheduled for June 29) we’ll know the air-tightness of the different methods. Then I can better approach the balance of effectiveness/materials cost/ installation time for all those future PH Projects.
Nearly every part of the Air Barrier will still be accessible throughout so I can [get] into and out of any leaky/sticky situations. Doughnuts & coffee for anyone who wants to be there for the fateful moment when the pressure’s really on…”

Here’s your chance to share your opinion:

[polldaddy poll=3384866]

Partners Insulation came out to blow the fiberglass insulation into the walls.  They are using a system called “BIBS” or “Blow in Blanket System”.  The insulation that Dan is using is from FiberTEK and is called InsulTEK1.  This is a formaldehyde free fiberglass insulation product that is blown into place.  The installers ran a long hose from the truck where the hopper and blower were, up through the stairwell and into the 2nd floor.  The first floor Larsen trusses were completely covered with OSB.  The access to the first floor cavities at the plates was wide enough for the hose to be slipped into the cavity and the insulation blown down into the first floor walls.

Here you can see where the 1st floor cavities on the left have been filled and the one on the right has not.  Once the first floor cavities are filled it is time to do the second floor.  The second floor bays are covered with a fabric which is stapled tightly across them.  The installer then introduces a hole near the bottom half of the bay to blow that section first.  The installer then creates a hole near the top of the bay and finishes filling the bay.  For all the requirements of a proper install, please refer to the documentation on the FiberTEK website.

As Dan was showing me around the site he noticed that an airtight seal had been applied incorrectly.  The rubber seal for one of the pipes had been taped in such a manner that there could be air sucked in through the joist connection.  The tape had been wrapped from the ceiling onto a joist, but that joist was not sealed.  Think about trying to tape over a corner of a wall – no matter how tight you try to make it, there is still going to be a void.  Dan removed the grey tape and re-taped the rubber gasket.  The grey tape was some left over “exterior extremely tenacious metal roof sealing tape” that Dan had.  The black was something else he had.  Another step Dan did was to staple through the tape to give it extra holding, but being careful to do that only in the areas that the rubber gasket was not.

After the OSB is put on the remaining walls and ceiling, Partners Insulation will be back out to blow in the attic insulation.  Then the sealing takes place in preparation for the blower door test.  I asked Dan about all the taping and he said he is going to try something different.  He has glued all the joints of the OSB as they were installed and is hoping that he will pass the blower door test without having to tape all the joints.  Sounds like we have a good experiment in the works folks!  Stay tuned for later this month when we see if Dan’s gluing saved him the time of taping or if he has gotten himself in a sticky situation!