January 2003 Update on Brooklyn project

At the end of a four-day blitz build over the MLK holiday weekend, SWA staff visited the site and found nearly uniform adoption of airsealing and insulation details, and some framing changes that greatly reduced thermal bridging. Further, the installation of high performance low-e vinyl windows was almost completed, and detailing at the frames was significantly better. Sealed combustion boiler units with insulated DHW storage are installed -- this slightly annoyed the plumbers who were forced to read instructions on the units prior to installation.

As part of the blitz-build, SWA and HfHnyc agreed to set a date for a blower door test for their first unit for building tightness; this would insure that they are nearing their goals for tightness to reach ENERGY STAR. The first unit was tested with the assistance of the Bedford Stuyvesant Restoration Corporation (BSRC) Weatherization Program on January 30.

The test was conducted without finished plumbing, electrical, or flooring, but with all windows, doors and sheetrock complete, and got a blower door reading of 2100 cfm @ 50 pa. This number will improve with the finishes on the building and after certain airsealing details are upgraded.

The additional good news is that in order to meet ENERGY STAR guildelines, the finished houses were required to perform at better than 2200 cfm@50pa, meaning that if construction management is uniform or better in the rest of the 20 homes, they will meet ENERGY STAR in NYS.

Continued Detailing Needed

Certain details need better scrutiny, not only in these homes, but in future single and multi-unit housing.

Air Sealing
Although the air sealing details are very good, certain plumbing and electrical sealing need to be improved, and existing airsealing endeavors need to continue to be strictly construction managed. Plumbing holes such as these need to be sealed as part of the heating punchlist. Similarly, plumbing going into walls needs to be sealed, as noted under sinks and at tubs and showers.

Leakage from unit to unit
Although the buildings were tested to be dramatically tighter than similar buildings of their design, leakage from house to house was similar to that of older brownstones. When one unit was depressurized to -50 pa, pressure diagnostics demonstrated that the adjoining building was depressurized to -15pa. This demonstrates that the leakage area to the outside of the building is only 20% greater than the leakage area between buildings. It is important for energy efficiency, health, and fire safety to reduce the leakage between units.

Framing
Two important framing techniques in general that need to be improved: Reduced use of metal in corners and general overuse of metal framing. Both of these cause excessive conduction through the wall, increase thermal bridging, and will reduce the effectiveness of insulation in the walls. The photo to the left shows a detail on a corner that is both impossible to insulate and a severe conductor of heat through the wall.

The photos below show two details where metal framing above the windows was changed use less metal. The first is very difficult to insulate and will reduce the overall effectiveness of the wall; the second is a vast improvement.

Overall, the increase in airsealing techniques and insulation practices will make these buildings meet ENERGY STAR, effectively making them the first ENERGY STAR buildings in NYC that were constructed by a not-for-profit agency. HfHNYC has moved mountains to change the way their construction is completed, and the field staff, particularly the Americorps, have worked hard to continue to teach these principles to volunteers in the field.

Content updated on 3/14/2003