This week the team finished up some taping, Gutex, and house wrap to prepare for strapping and siding.

Now that the electrical rough-in is finished, there are quite a few spots where wires are protruding from the interior to the exterior of the house. This is necessary for mechanical systems such as the HRV, sill-cock penetration, ASHP line set penetration, and and some exterior lighting and duplex connections; all which require creating penetrations in the process. Before we finished up the rest of our Gutex panels, some members of the team spent the first half of the day detailing and taping these penetrations which returned the house to an airtight enclosure.

Simultaneously, some other team members followed the tapers to fill in some of the gaps in our Gutex layer. Ever since the Gutex arrived on site it has been a star studded material. Nobody including the instructors have worked with the material before so everyone has been curious about its characteristics and installation process. I have found it is easy to cut (especially with a table saw), it is light enough for one person to handle, it does not cut you up like fiber glass or other insulations, and it can be fully exposed to rain without affecting its performance. It will be interesting to see how this material stands up to the test of time, if you want to learn more about the material, the experts at 475 High performance Building Supply dive deeper into the subject. However, if a section of Gutex needs to be taken out and replaced, it can be a challenging process. Each piece is made of wood fiber so when trying to rip one piece out, it creates a lot of friction. Removing a piece of Gutex often results in big tears, so it is ideal to install it correctly the first time. In addition, Gutex is tongue and grooved on all sides in order to create a continuous thermal layer, so removing a section creates a noncontinuous joint of insulation. In order to fix this problem, the crew has been using Visconn (a liquid applied air barrier) donated by 475 High performance Building Supply which when used correctly returns the insulation to a continuous layer. Even a small crack in our thermal barrier will affect the energy use of this house so it is important to leave no stone unturned.

Finally, we finished the day with another layer of Weather Resistant Barrier (WRB) over the Gutex. Like the other WRB, this layer will wrap under the house and attach to the Zip System Insulation Board beneath the floor joists. The House Wrap will easily staple to the Zip System Insulation Board and be detailed with Tescon Vanna tape to compete the air barrier, but we found that the WRB does not staple well to Gutex. The wood fiber is hard to the touch, but is not dense enough to hold staples. The staples will hold for a little while, but a brisk wind will rip off the Gutex without hesitation. We found that a few strips of tape around the perimeter of the WRB remedied the issue.

The strapping for our siding will be installed next weekend and will create a strong connection between the WRB and Gutex. In addition, we hope to get well into siding on the following weekend! Then cellulose insulation, Intello, Dry Wall and before you know it, trim, cabinets and countertops will be installed along with finish flooring and painting. The HyggeHaus is almost ready for the Green River Festival, so make sure to stay tuned for the last few weeks of the Build!

Hello longtime readers and new readers of the HyggeHaus blog! Yes, you! The Building and Construction Technology (BCT) Program is asking for your help during UMassGives to raise funds for the Design-Build Program that has made this semesters build possible. If you are a first time reader, feel free to check out the the work we have completed so far in the posts below.

This project is a collaboration between BCT, Architecture, Five College Architectural Studies Program, and East Branch Studio, with L. Carl Fiocchi leading it from our program’s side. I would also like to give a shoutout to our sponsors 475 High Performance Building Supply, Eco Buildings Bargain, Graham Electric, and John Thomas Plumbing and Heating for their outstanding support.

Our team has been busy building the first of what will hopefully be many dwellings that – after completion – will be made available to affordable housing associations and others. For students, this offers an amazing hands-on opportunity to learn about the various aspects of high-performance buildings and construction. Specifically, it teaches about construction practices, low load mechanical systems selection and installation, performance verification, and carbon accounting. I am a senior in the BCT major at UMass Amherst who has had the pleasure of participating in this project, in addition to writing the blog alongside coauthor Lia Douillet. This has hands down been the best academic experience I have experienced in my four years here. The BCT courses I have under my belt are enlightening as is, but the opportunity to apply this knowledge in the field is something I would recommend to all my peers. The whole team has enjoyed witnessing the fruits of our labor ripen, and it will only get better throughout the years.

We are hoping to raise funds during UMassGives in order to support this project for future years. Gifts from our community of alumni, friends, faculty, parents, staff, and students will help us get there! 

Please join us in this important effort and inspire the generosity of others by sharing on social media! Thank you!

Learn more about what we do in BCT: https://bct.eco.umass.edu/ and stay tuned with our blog to see the completion of the HyggeHaus in the next couple months!

This rainy Saturday was the perfect day to stay inside and learn about plumbing from the experts at John Thomas Plumbing and Heating. To start the day off, their team led us through the steps of plumbing installs, including Pressurized Lines, Waste Lines, and Venting, plus a Ductless Mini-Split Heat Pump installation. A bonus was a demonstration and hands on opportunity for sweating copper piping and fittings.

At the copper soldering station, students took turns testing their skills with a torch, flux, and solder. The first step to forming a leak proof copper pipe connection is a clean surface where the copper pipe and fitting will connect. Any type of sandpaper can be used to abraid the outside surface of the pipe and inside the fitting where the pipe will be inserted. Next, flux is applied to the outside of the copper pipe and inside the copper fixture. Flux is essential in this process as it emulsifies oil on the copper, allowing the acidic chemicals in the flux to lift dirt and oxides off the surface. If any oxides are left they would corrode the copper pipe leaving small leaks (or worse) which can lead to mold build up in cavities, structural deterioration, or associated flooding issues. Then, with the help of a torch, the solder is brushed along the copper connection and “sucked” (capillarity) into the joint creating a leakproof connection. Last but certainly not least, the finished connection must be wiped with a rag to remove excess flux which can also corrode copper if left for too long.

While students improved their soldering, another group observed the layout for the Ductless Mini-Split Heat Pump which will eventually live on the East wall of the HyggeHaus. Back in 2020, the design team chose this unit as our main source of heating and cooling because of its high Coefficient of Performance (COP). COP is equal to the power output divided by the power input of a unit and represents the efficiency of HVAC systems. For instance, our Ductless Mini-Split Heat Pump has a COP of 4 meaning it will produce 4 kW of energy for every 1 kW of energy used. This is a substantial improvement compared to electric furnaces or baseboard heaters which have a COP of 1. Another reason the 2020 team chose this unit is because it would have efficiently utilized the energy produced by the Photovoltaic System planned for the roof. As mentioned in previous posts, the HyggeHaus will not be able to host Photovoltaics due to a lack of direct sunlight at its final destination. Regardless, a Ductless Mini-Split Heat Pump will be cost effective, and more indoor units can easily be added if needed. The unit will not be installed until the latter portion of the build, but the piping (lineset) for refrigerant and condensate drain line are now waiting patiently in the wall to be utilized. The condensate drain will direct water into a 50 gallon rain barrel that will sit outside the house. We estimate the condensate from the mini-split will produce enough water to fill up the rain barrel about every 2 weeks when the unit is running 24/7. By storing this condensate for later use, the HyggeHaus occupants will be able to water their plants, wash off their bikes, or have water balloon fights without increasing their water intake.

To finalize our day of plumbing and HVAC, another group installed hot and cold water lines for the sinks and shower which were wrapped in pipe insulation to reduce heat transfer. This was accompanied by a waste lines and venting. Undoubtedly the most fearless and noble member of a house, the waste pipe carries your undesirables from the toilet to the septic tank or municipal sewer along with grey water from showers and sinks. Despite the waste pipes heroic role in a house, the plumbing system would not be possible without the vent stack which regulates air flow throughout the system.

The next day consisted of priming the tongue and groove siding which will make up the facade for the HyggeHaus.

This weekend the design build crew was very excited to walk on site to a raised roof! Kent and an East Branch Studio team set the front knee wall, followed by roof’s wooden trusses, which are anchored at ridge and eaves with 24 foot LVLs. Zip sheathing was then fastened to the trusses creating the roof deck and taped at the seams as further insurance against air leakage. The addition of the roof gives the structure a whole different feeling along with the added benefit of providing a dry space for work and storage.

The race to get the house “dried in” continued this weekend with more sheathing, Solitex Mento House Wrap, and Tescon Vanna Tape. We also prepared the window openings for window installation, adding window bucks that extend past the framing. This is necessary to accommodate the thick layer of outboard insulation and strapping which will provide attachment points for siding.

The addition of the roof reopened the debate over the possibility of adding a clerestory window. Meghan, an architecture grad student on our team, drew two options showing the clerestory window’s impact on the North and South Elevations which will be dependent on the final orientation of the building’s roof as will be determined by solar access at its final site (more on this in upcoming posts). The team felt this would break up the vertical shipped lap siding on the tall South Facade that is now quite prominent. Furthermore it would provide additional daylight to the interior and make the living room feel more open. With the knee wall in place, adding a window would have required modifying the existing framing. Also, the living room already has plenty of glazing area between the windows and doors; in light of this, we again decided against adding the window.

Now that the framing, sheathing, Weather Resistant Barrier (WRB) installation, air sealing, and window prep are nearly finished; the window and door installation is the next step on the critical path. This is a necessary prerequisite for rough electrical work, interior and exterior insulation and finish work, and ultimately, testing the building for airtightness. As the team works on wrapping up this phase of construction, we are enjoying watching the process of the Hygge House developing from an idea towards a finished product.