Archive for August, 2011

After the storm

Anticipating flood potential, we covered everything in plastic.  With hurricane Irene gone, we went to assess the damages.  It turned out that our foundation, the newly built floor system and the site in general, fared well during the storm.  Irene did not hit Arlington/Northern VA super hard but it did dump a whole lot of rain on us.  So, when Eric saw the site this morning, the only difference he saw from Friday was ” a little muddy.”

It really could have been a lot worse but we really got lucky.

Well, we can say that our house survived several earthquakes and a hurricane.  All in the same week too!


Floor System Building

Intellistructures started building the floor joists today.  First, they secured the sill plate.  Then, they hanged these nifty Simpson joist hangers 24 o.c. directly on the sill plate and draping down on the concrete studs of the Superiorwalls.  The SW concrete stud-face will provide an excellent place of support for the joists once they are set into the hangers.

This is cool because these hangers eliminated the need for the band joist (see below).

In conventional building, this 2″ thick piece of lumber is the only thing between the inside of the house and the outside.  Since it surrounds the entire outer envelope of the house, it is frequently one of the weakest points in air-tightness and if not insulated properly, it is prone to heat loss.  Using the joist hangers allow us to completely eliminate this weak point altogether and our floor joists look like this:

The subfloor will sit directly on top of the floor joists. The SIPs (Structural Insulated Panels) will sit directly on top of the sill plate.  No band joist to worry about!

We used I-joists to build the floor system.  This is a relatively common practice that replaces the traditional 2 by solid lumber with I-Joist, an engineered wood product that consists of recycled wood pieces and smaller pieces of solid lumber.  It is not only more sustainable, it will not bow, crown, twist, cup, check, or split as would a dimensional piece of lumber.

The crew also installed a ginormous piece of steel  today.  A 31 ft long steel column that probably weighed literally a ton.  I am still not sure how five guys did it without any visible equipment.

Well, it’s there and it’s secure.  So, I won’t ask any questions.

After the Shake

We are very happy to report that after yesterday’s 5.8 earthquake and a number of after shocks, Weaver’s Superiorwalls are intact.

Since we still haven’t backfilled yet I was quite concerned about the safety of the Intellistructures crew who were working on the floor joists above the walls.  Apparently, Charlie had his crew trained to walk the balance beam really well so no one fell!  Can they do other acrobatics?

Secondly, we were concerned about the walls moving because there were no external support from the backfill yet.  This morning, we carefully examined the wall connections to the crushed stone footing.  There were no visible shifting or movement from where the walls were originally placed or any loosening of the gravel footing.  So, at this at this scale and at this magnitude, I agree with Frank Lloyd Wright’s observation that crushed stone footings are “perfectly static”.

We also examined carefully each of the panels for any damages or cracks.  There were none.  So, good casting Weaver Precast!

We carefully examined the concrete slab poured last week.  The slab looked great and the strength of that slab probably contributed to the foundation holding together too.  So, good casting North Star!

Where do we go from here?

The Passive House community here in the U.S. is still processing last week’s divorce between PHI and PHIUS.  The two organizations have accused each other of breaches which may have led to the ultimate break.  On the ground, Passive House consultants, designers, green building advocates, bloggers and other observers are drawing lines in the sand and speculating who started the fight and the “true cause” of the breakup.  This is beginning to be like trying to figure out why your parents got divorced.  Yes, it is sad and painful but let’s face it, we’ll never really know.  As someone wise once told me when I got married, “when couples fight, 75% of the time the parties are fighting about completely different things.”  So, PHI and PHIUS probably don’t even know for sure.

Enough about that!  What we need to do is figure out the way ahead.  The important thing is for all of us in the PH community to learn something from this, pool our resources together and perhaps build a structure for the Passive House in the U.S. that is more robust and effective.

Is PHIUS obsolete?  I don’t think so.  They still have the experience of building and certifying PHs, a network of people they trained (me included), the political people they met along the way and the various relationships they maintained.  As Adam Cohen pointed out at both (PHI and PHIUS) are “equally guilty of terrible customer relations, with inquiries going unacknowledged and support when it does come being abbreviated.  I think this is a great opportunity for PHIUS to change they way they think and operate.  Without the backing and reputation of PHI, PHIUS needs to think and operate like a business that “means business”.  There is absolutely nothing wrong with being “grassroot” but it must have strong systems and an organized infrastructure, along with in the right people, possibly some money in place to really make things happen.  Let’s face it, we all love the passive house approach to building but that is because we all care about green building enough to want to understand it on the deepest level.  How many people can you pay to sit through a Therm Analysis presentation?  The science works but we need to sell it!  PHIUS needs to establish Passive House as the performance green building brand and it needs to really sell it to the government of all levels, corporations and the common folks.  Otherwise, what is PHIUS’s certification for its consultants or buildings worth outside of this circle?  They need to do it because their survival really depends on it.  I think all of us PH consultants, builders and designers are willing to help this cause.  So, please let us help.

A U.S. based certifying body under PHI must and probably will emerge quickly to fill the void.  Now, what happens if this certifying body gets dumped by PHI or if it dumps PHI in a few years?  We’ll be back to where we are.  So, I think the stakeholders (the entire PH community) need to figure out how we individually or at least as regional groups want to affiliate with the PHI and with the greater IPHA.  International co-operation can only grow in importance as the movement matures and we can’t have a broken link there.

As Kat states in her response that Passive House as a standard, “belongs to no one or no organization”.  This is very true, even our laws reflect that, an idea or approach cannot be protected by copyright laws.  The goal is to spread this approach as far and wide as possible for anyone who is willing to learn to learn it and build, retrofit homes for the future (not of the future).  I think we are at a critical juncture for something great, so, let’s stop wasting energy fighting and get our heads together and really bring this to mainstream.

“I break with thee… I break with thee… I break with thee… then throw dog poop on her shoes”

So, the Passivhaus Insitute(PHI) in Germany decided to break up with Passive House Institute U.S. (PHIUS).  I really don’t know how this will ultimately impact the Passive House movement in the U.S.  I think in the short term, the impact will be pretty negative.  The fact is the U.S. no longer has a certifying body that can give out certifications on houses designed and built using the PH approach.

Dr. Feist stated that any of the other certifying bodies in the world can certify any project worldwide.  He is correct to state that the physics is the same.  However, I believe climates, building materials, custom and other factors all influence how a house is designed, built and viewed. The physics may be the same but there are bound to be lack of understanding with unfamiliar issues specific to regions of the U.S.  For example, most of the Passivhaus approach was created in climate zones that do not require much active cooling and do not experience high humidity.  The PHPP (Passive House Planning Package–Our energy modeling software) shows a clear lack of sophistication in cooling needs when comparing to the extensive heating sheets in the same program.  Here in the U.S., PH designers have been able to use PHPP’s cooling sheets but consult their own HVAC engineers for more detailed calculations partially because PHIUS is an organization run by people who are familiar the cooling needs in some parts of the country.

This is not an issue purely about climate.  There are many cultural issues at play here too.   If the PHI Passivhaus brand wants to continue to grow acceptance and in number of projects here in the U.S. they must find another certifying body in the U.S. as soon as possible or perhaps since the U.S. spans so many climate zones, instead of one, have several regional certifying bodies.

On the other hand, PHIUS seems to be “going it alone”, according to Dr. Feist.  This may not totally be a bad thing, either.  PHIUS can take this opportunity to grow without the directives and restrictions from PHI.  The original Passive House concepts came from the U.S. with the superinsulated homes built in the 70s.  Perhaps this is the time for PHIUS to start looking for its real roots and building its own name recognition.

Come to think of it, does the brand matter if the houses perform? The beauty of Passivhaus/Passive House is that as long as the energy performance criterion are met, it is a passive house. But in this world that places so much importance on name recognition, certification unfortunately matters.  I wish it didn’t but I think it is nearly impossible to get the majority of the population to understand the underlying concepts without giving it a brand.  I hate to say this but the folks behind LEED are experts salespeople and it is because of their sales and marketing skills that when people hear about green building, they immediately think of LEED.  What is the reaction you get when you mention Passive House? More than half of the time, I get “oh yeah, I know about passive solar!”

It seems such a shame when the U.S. is on the verge of entering a period of exponential growth in the most stringent performance based green building approach that this has to happen.  Well, we’ll all see what happens soon enough.

On a separate note I think the implementation of Passive House will spread wider and faster if instead of a certification process pre and during the build, you have a testing/monitoring system to see if the house after its completion is indeed operating at a “Passive House compliant” level.  Our friend Al Cobb’s ECOP system that is in beta testing does exactly that.

Anyways, here’s the open letter that Dr. Wolfgang Feist wrote yesterday and PHIUS’ Response.



Building a bullet proof slab

After last week’s below slab insulation, the next step was to install a strong vapor barrier, rebars and concrete.  We wanted a very very air-tight and water-tight slab.  North Star Foundations answered that request with rolls of 15 mil Stego Wrap, the vapor barrier of choice for Passive House builders.  We had only heard about the material, but when we saw and felt it, we were immediately impressed with the strength and thickness of it.

See here for more info on Stego

To give people an idea of how this vapor barrier compares with most vapor barriers, most homes use a 6 mil vapor barrier that feels like a thick garbage bag, the Stego is so thick that it is difficult to penetrate with nails.

North Star painstakingly installed the wrap, taped the joints and all the penetrations.  In order to ensure the we have a nice sealing edge, the wrap was pulled up and temporarily secured onto the wall studs, which we will trim off when we are ready to seal the perimeters.  See below:

North Star fabricated and laid steel reinforcements into the thickened slabs and footings.

We were ready for the pour.  The concrete was mixed with nylon fibers to help minimize cracking as the concrete dries and shrinks.  Using the nylon fibers also means we did not need to build wire reinforcements, saving time, money and resources.  This entire process was a huge scramble between foam insulation, slab building and inspection.  On top of that, our plumbers decided to come and connect the sewer.  The weather was again a huge issue too because when it rains a lot, our 6 inch foam insulation without the concrete holding it in place becomes a giant floatation device, so we wanted to pour the concrete as quickly as possible.  The concrete supplier showed up way late in the afternoon which caused work to continue into the evening.  Sorry neighbors!

North Star did a kick ass job getting everything done within a small window of time.  The result is the air and water-tight slab we were looking for.  It’s probably bullet proof too, though we did not test it.

Our Inigo Montoya

Do you remember this scene in the Princess Bride?  Inigo is using his father’s sword to guide him so he can find the man in black.  Well, Peed Plumbing has a talented plumber on their crew with a gift that helps him locate difficult to find sewer pipes.

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