In advanced framing, we bridge the corners with ladder blocking instead of the 3-stud corners used in conventional framing. This technique not only uses less wood, but also allows you to get insulation into the corners. The studs are spaced 24 inches on center with single top plates and the roof trusses are “stacked,” meaning there is vertical alignment, to create a direct load path. Advanced framing maximizes the wall cavity space where dense packed cellulose insulation will be blown in, reduces thermal bridging and creates a tighter building envelope.
Today was the initial blower door test at the Kamp Kaolin site. With all the passive house building methods used at Kamp Kaolin, we were very excited and confident going into the test. In the above picture is David Berg (right) of DSB Energy Services and Hugh Lofting (left) are installing the frame of the blower test in a window because the door openings were too large for the frame. Kamp Kaolin came in at 0.88 air changes per hour (ACH) at 50 Pascal, which is very good! After the dense packed cellulose and dry wall are installed this number should go down. The passive house standard is 0.6 ACH at 50 Pascal. Even though the Kamp Kaolin project is not going for certification, we are striving to hit all the passive house standard milestones.
In line with passive house building principles, the airtight building envelope begins at the foundation and is continued throughout the entire construction process and the entire house. The under-slab vapor barrier, the yellow wrap, is placed on top of 2” of EPS insulation and then is covered by an additional 2” of insulation. Basically, the vapor barrier is sandwiched between 4” of EPS insulation. All of the seams are taped to insure an airtight barrier. Rebar is then installed in a checkerboard pattern to reinforce the concrete, prevent cracking, and provide structure for the PEX tubing to be attached to. Finally, the concrete is poured. The yellow vapor barrier will be taped up the side of the house, on top of the wall vapor barrier, on this project, the Zip System, to continue the building envelope. The next post will discuss our advanced framing building techniques.
HJLCMS is proud to debut its first video on passive house building methods.
The Kamp Kaolin Passive House Building Methods – Air Barrier video goes over the transition of window openings into the air barrier. Each component outlined in the video becomes a part of the air barrier for the entire building shell.
Scheduled for completion in November 2014, Kamp Kaolin is a high-performance 2,700-square-foot private home on a secluded site in Chester County, PA. HJLCMS collaborated with the homeowners and architect Townsend Moore of Tick Hill Studios. Design and construction for the project are based on passive house principles and building science. Building science focuses on the analysis and control of building materials and building envelope systems. In this case, building science is informing a passive design. Passive houses generally achieve energy savings of 60-70 percent through super-insulation and airtight building envelopes, highly efficient HVAC systems or energy recovery ventilation, high-performance windows, and moisture control. Kamp Kaolin incorporates air and moisture barrier zip systems and super insulation as well as a closed-loop pond geothermal system for extremely efficient heating and cooling. The 2,700-square-foot house also features aging-in-place amenities (roll-in showers, single-floor living), advanced home automation systems (systems and lighting controlled via smart phones and tablets), the warm beauty of timber framing, and integration of indoors and outdoors through an open floor plan with few interior walls, an expanse of windows on the rear of the house that provide pond views, dual rear porches – one open and one screened – and natural, limited-maintenance landscaping.