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Posted from: MD, USA

Posted from: MD, USA

We have accomplished a lot since our last post.

First, we laid a 6” gravel bed down over the soil. This provides a capillary break between the concrete and the soil, preventing the slab (basically a big sponge) from sucking up moisture from the soil below. Standard good construction practice.

After the gravel was tamped level and compact, we placed 4” of EPS Geofoam over it. The EPS boards were laid tight together, with no gaps. One of the photos is taken just as the vapor barrier was about to be laid. You can see the foam is held back to allow the concrete slab turn down and rest directly on the concrete footing at its perimeter. Another picture shows the basement grinder pump set in its insulation bed. Mid Atlantic Foam took the crock and the radon crock to their shop and fabricated foam cradles for them. Bartley Concrete then simply made a depression in the gravel, and set set the cradles with their tops flush with the top of the rest of the foam, and dropped in the equipment.

While the foam was being put down Bartley was also applying the waterproofing membrane to the exterior of the sub-grade foundation wall. In one of the photos you can see the membrane going down to the top of the footing. The temporary foam form has not yet been removed. When it is, they will apply the waterproofing with a roller all the way down the sides of the footings as well. Friday the 3rd was a big day. After all the sub-slab foam was in place, Bartley installed and taped the vapor barrier. We also had a surprise visit from Katrin Klingenberg, Director of the Passive House Institute U.S!

The pictures show the 15 mil Stego polyethelene vapor barrier (http://www.stegoindustries.com/technical_info/_stego_wrap_15-mil_vapor_barrier.html) all laid out and taped up. We chose the StegoWrap over the standard 6 mil barriers because you have to really want to cut it or tear it in order to do so. Draping it down under the footings and up the wall, we wanted to be sure nothing inadvertently punched holes in it. All joints were taped continuously, and as you can see in the photos, all penetrations were fully double-taped as well. We temporarily tacked the edges up along the foundation walls until the slab is poured. Bartley will then come back and anchor a continuous metal termination bar along the top, mechanically fastening the barrier to the concrete. Katrin was in DC doing a training course for Passive House consultants. (http://www.passivehouse.us/passiveHouse/PHIUSConsultantsTraining.html) Of all days Katrin could have come, this was the best. It was a first for all of us at taking these extra steps of sealing, and having her go over our work and pronounce it first rate before the concrete went in gave us all a big boost.

On Monday, after Keith made a final check of all the taping, the concrete trucks rolled up and poured the floor slab. I dropped by the site today and include a picture of the finished slap, with only the top of the vapor barrier peeking out. Another picture shows the same penetrations we photographed earlier, now encased in concrete and sealed tight. The group in the picture, left to right:
Keith, Katrin, Brendan Jr., and Terry Hill, another Passive House consultant.

Posted from: MD, USA

Foundation walls are now up, and the construction forms are off. Next
steps will be waterproofing the exterior of the walls, then applying
the underground insulation and drainage board. Tammy Fuller from
Mid-Atlantic Foams was at the site measuring for insulation quantities
when I visited and left us a sample of the insulating drain board (see
photo below).

This two inch thick board is designed to provide a “drainage plane”
for the wall, creating a capillary break and channeling any water that
gets to the wall down the face of the wall and into drains placed at
the footings. It is composed of small foam balls which allow the
passage of water. It is coated at its outside face with a layer of
fine mesh (“geotextile”) which allows the passage of water but keeps
dirt out. In our case this 2” board will be laminated to a another 2”
thickness of expanded polystyrene insulating board designed for
underground application.

Creating a drainage plane in this way is not particular to Passive House construction; it is simply standard good construction.

Pictures below:

The walls from above and from inside basement.
The insulating drainage board.
Brendan O’Neill, Jr., Tammy Fuller, and Keith Kauffman

Posted from: MD, USA

Yesterday we erected all the exterior wall forms, and today we will
pour the foundation walls.

Air sealing is critical in Passive Houses. To prevent any potential
air leakage, we have minimized and clustered the number of
penetrations through exterior walls. At our preconstruction meeting
all subcontractors submitted exact locations of where they need to
penetrate the building envelope, and worked together to consolidate
those holes. We have placed sleeves in the formwork for all
penetrations, which will later be sealed and insulated.

Here are a few images:
* a short clip of erection of the forms;
* Keith Kauffman, Jobsite Superintendant, who is keeping it all on track;
* rear frost wall footing with wall steel in place;
* and a general view from the front yard. In the distance you can
see the variety of houses in the neighborhood: two large new houses on
the left and an older original house on the right. Our foursquare will
be in the middle of that spectrum size-wise.

Posted from: MD, USA

To prevent thermal bridging (short circuits in the insulation system)
the complete building envelope of a Passive House is insulated. In our
case, this includes the footings. In this little film clip you can see
that in progress.

After excavating the trenches for the exterior wall footings we put
down a “mud slab”— basically a thin coating of concrete over the
earth which could then be trowelled level. That gave us a nice flat
surface to lay our insulation down on. We then put down 4” of high
density expanded polyethylene (EPS) foam.The concrete is then poured
over that.

The sides of the outside wall footings will be insulated with 4” EPS
as well. You can see the white EPS on the interior face of the
footings. It does double duty as a form for the concrete. On the
exterior side of the footings you see the insulation is a different
color. This insulation board is used as a form for the footing and
will be removed. Why? Because we are waterproofing the exterior walls
right down to the sides of the footings. Once the concrete walls are
poured, we will apply the waterproofing membrane, then come back and
insulate the entire wall and sides of footings with the EPS foam. The other two footing photos show the footing for a pier inside the house before and after the concrete is poured.

Posted from: MD, USA

There were two big developments last week. We cleared the site, and we received our building permit.

This week is off to a fast start.  Footings are already poured, and forms go up tomorrow for concrete foundation walls.

But before getting into the construction issues, a note about how we chose this particular site. I would like to say that our decision was based solely on Passive House planning principles.  The real world, however, is messier than that. The beauty of the Passive House approach is that it is designed to handle real world situations—even sites that don’t have ideal solar orientation. That’s another reason it works so well for the designer.

When we decided to undertake the project, Brendan (O’Neill) had already purchased this site for future development.  It made sense to use it and to fit our house to it. The neighborhood is undergoing the usual transition that close-in 1930’s neighborhoods in most growing major cities face. The increasing land values make it unfeasible from a real estate payback standpoint to retrofit and renovate the existing smaller houses.  Once the original owners are gone, these houses often become rental properties, held until the increasing land value makes it profitable to sell for the value of the site alone. With no owner incentive to maintain them, they deteriorate.  When they are finally torn down to make way for larger houses, they are usually in pretty rough condition.

This was the case with our property.  A small 1930’s cottage was financially unfeasible to renovate. Several houses on the street have already been replaced. On this site we decided that if we were going to replace the existing house with a Passive House, we would do two things:

1.       Keep as much of the house as possible out of landfills, and

2.       Try to build more or less on the footprint of the existing house.

On the first point, we contracted with Second Chance http://secondchanceinc.org, a non-profit that goes through homes slated for demolition removing all items that can be resold—cabinets, appliances, fixtures, doors, hardware, etc. We then contracted with Roll Off Express http://rolloffexpress.com in Finksburg, MD to salvage all materials possible.  ROE set up dumpsters on the site where all demolished materials were placed. They were then taken their facility in Finksburg for sorting and distribution to the appropriate recycling streams.  We will be given an accounting of quantities of materials recycled within a few days.

Below are pictures of a typical existing house in the neighborhood and a typical new house in the neighborhod.

More on the footings and foundation in a later post…

Today site clearing begins for the first Passive House in the DC area! Read our press release below…

Alexandria, VA (August 16, 2010) – On August 16, in a quiet residential neighborhood in Bethesda, MD, site preparation work will begin on the area’s first Passive House, a building standard that is the only affordable way to seriously institute building practices that address climate change. The project is a joint venture between O’Neill Construction Corporation, of Gaithersburg, MD, and Peabody Architects of Alexandria, VA.

 

Consumes Ninety Percent Less Energy

Passive House (from the German Passivhaus), now taking hold in the United States, is a leading green-building standard in Europe and the most stringent energy certification standard in the world. It produces buildings that use one-tenth of the heating and cooling energy of conventional buildings, while adding, on average, only 10 to 15 percent to the cost of construction. In larger building types, such as schools and office buildings, this standard is easier to reach and the cost differential versus a conventional building runs even lower. With a new energy bill going up before the Senate this summer, the time could not be more auspicious for the arrival of the Passive House in Washington, DC.

 

The Passive House approach produces buildings that need so little energy it makes irrelevant the more glamorous and expensive high tech solutions – photovoltaics and geothermal heat pumps – that get most of the attention in terms of tax incentives. It is accomplished with the most prosaic and affordable of materials: lots of insulation and sealants. What makes it all work are highly sophisticated energy modeling software and an assiduous approach to eliminating thermal bridging (the rapid transfer of interior heat to a cool area) in the building envelope —all developed by the Passivhaus Institut in Darmstadt, Germany. Studies conducted on the thousands of European projects completed over the last 15 years have uncovered an additional advantage to this construction approach: very high levels of interior air quality and extremely high ratings for comfort.

 

Efficient, Attractive, Affordable Home

The O’Neill-Peabody project, designed in the Craftsman vernacular of the American Foursquare, is out to demonstrate that this exotic sounding European import can look and feel like a traditional American home that sells at a competitive price. Brendan O’Neill Sr., whose firm has built its reputation by recreating traditional building styles, was interested when David Peabody told him about the advantages of Passive House construction, but knew that his customers would not get excited about a building that looked like a box. O’Neill and his son visited two recently completed Passive Houses in Illinois—as it turned out, right in the middle of a true Midwestern blizzard.

 

“It was as toasty and comfortable as any house I’d ever been in. I looked in the mechanical room and the little heat pump was barely even running. I turned to Brendan, Jr. and said, ‘We’ve got to build one of these.’”  Brendan O’Neill

 

The project will be completed in spring of 2011.

 

For more information on this project, the team, and the Passive House program:

http://www.passivehouse.greenhaus.org

http://www.passivehouse.us/passiveHouse/PHIUSHome.html

http://www.passiv.de/index_14PHT.html