Energy Revolution in a Brooklyn Townhome
We have spray foam – the first phase of it anyway! Most of the front and back walls, as well as 3 feet of the party walls on either side, were covered with 3.25 inches of foam yielding a 23.4 R-value. After 3 months, that R-value will drop to 21.5. An R-value of 21 is the specification set by the passive house consultant. The windows cavities were left un-sprayed for now. We will have a second phase of spray foam when the frames for the windows are installed. Every opening of our 23 windows are a different size, some by as little as an 1/8 inch, so it is best to wait until the windows are in before adding the foam to those areas.
We found a nifty, inexpensive way to deal with airsealing the electrical boxes in a retrofit capacity – Lessco boxes. We simply cut out the sheetrock around the box location and install the Lessco box – into which the electrical box can be installed. Any penetrations made through the box can be caulked before the sheetrock is replaced, and if there is still some leakage after everything is put back together, this box can be filled with spray foam right through the sheetrock.
More to come in the next 2 weeks as the windows are ordered, the solar hot water system is installed, the ventilation system is installed, the plumbing inspection completed and a blower door test to indicate how well the house is sealed thus far. After these elements are complete, we can begin closing up walls and moving forward with the finish elements of the house.