Passive-House Remodel in A Historic Neighborhood – Fine Homebuilding

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Written By Jim J Neal


Synopsis: Trey Farmer, an architect, and Adrienne, an interior designer took their 1914 Craftsman-style Austin home and made it Passive House certified. The house was located in a National Register Historic District and had to blend into the surrounding neighborhood. They wanted to preserve as much of the structure as possible while creating a more healthy indoor environment. Adrienne and Trey consulted other professionals in the region to make upgrades, such as installing insulation and a balanced HVAC system. They also added a modern addition that will increase the square footage without sacrificing the traditional facade.

Our 1914 Craftsman-style home, just outside of Austin, Texas, is an example of Passive House renovation. It has been certified PHIUS+ 2018, and received PHIUS+ Source zero Certification. This home is located in a hot, humid environment. The renovation was both a personal as well as a professional mission. Adrienne, my wife, and I purchased the house over a decade ago, after falling in love the area. It was always in our minds what it could become and we planned to make it more modern. We saw this opportunity to show the potential for a small, healthy, high-performance home, based on my experience as an architect at Forgecraft Architecture + Design and Adrienne’s emphasis upon sustainable interior design at Studio Ferme.

We improved the building envelope which was not properly insulated, added square footage with modern additions, and designed a flexible floor plan to suit our family’s needs while keeping the historic structure intact. We also added a 6.3kw solar array and battery backup to our Passive House project.

Start from scratch

We wanted to preserve as much of the original structure as possible as it is in a National Register Historic District. To discuss our changes, we met with Preservation Austin’s friend. Although the original plan was to save the entire framing, once we saw the extent and severity of termite and water damage, we changed our plans. The original structure was saved by the columns and porch. (The piers were rebuilt in the 1980s).

Save face – The original plans were to preserve the framing but structural damage prevented them from achieving their goals. So the home was rebuilt. However, the facade at the front elevation was retained and integrated into new structure.

We started from scratch and were able to move from 2×4 framing, to 2×6, which allows for insulation to be placed deeper in the walls. A foundation measuring 2 inches was also addressed. Out of level. To support the addition, new piers were built to level the remaining structure. To make up the gap between existing piers, steel shims were used.

We worked with Hugh Jefferson Randolph, a local architect who specializes in modern additions to historic houses (see below “Adding to historic homes”). We increased the square footage by replacing the rear half of the floorplan with a modern addition. It was 1400 sq. From 1400 sq.ft. to 2100 square feet. ft. to 2100 sq. We added a light well to the kitchen, as well as architectural details such as different ceiling plans to create spaces. Additionally, we added full-height windows and modern details throughout the space for a cohesive look.

An open floor plan defines the house. You can make the playroom/guest area a part of your living space, or separate it with large double doors. This will allow you to have privacy when you need it. The Murphy bed is a flexible furniture option that allows the space to be used for multiple purposes. Modern windows and daylighting make the living, dining, and kitchen seem larger than they actually are. Pocket doors provide privacy and separation, and can also be used as sound barriers.

Connection with Nature – The primary bedroom has natural light flooding it. It also has access to a shaded porch.

Warm and welcoming – The short hallway that separates the main living space from the open-concept main area is lined with reclaimed shiplap. It conceals the laundry room and adjoining powder room.

Dramatic details add drama – A light well in the kitchen and bathroom-suite shower maximizes natural lighting. Overhead lights are seldom needed during the day.

Space-saving solution – The former attic space was converted into a conditioned loft, which added more square footage to the first floor without affecting the plan. This flexible space can be used as a playroom or guest bedroom with a Murphy-bed.

Investing in the envelope

We made insulation our top priority after living in a 100-year-old house for 10 years. The walls and floor were not insulated. There was also no fiberglass batts on the roof. Because of the environmental impact of spray foam insulation and concern about indoor-air quality, we decided to not use it in the interior.

SPECS

Bedrooms: 3 Bathrooms: 2-1/2
Size: 2210 sq. ft. Cost: $375/sq. ft. (incl. Screened porch
Completed: 2022 Location Austin, Texas
Architect: Forge Craft Architecture + Design
Builder: CleanTag LLC

Cavity insulation was done in the roof and walls using mineral-wool batts. Mineral wool is more resilient than fiberglass and retains its shape longer than cellulose or fiberglass. Zip System R-Sheathing was used to cover the roof and walls. It has an integrated rigid insulation system and water-resistive barrier. Because we had already overcome existing setbacks, this all-in-one solution allowed us to “hide” continuous insulation behind the sheathing in order to meet our insulation goals.

It was important to preserve the historic facade of the front porch. However, air sealing is difficult when connecting an older porch with a newer construction. It was obvious that there was a weakness in the air barrier as the blower-door test resulted in a reading of just 1 ACH50. AeroBarrier is a method that seals air through the air and presses it against a blower door to achieve Passive House airtightness of 0.6 ACH50. I reached out to a friend to help me.

Next blower-door test was 0.3 ACH50. This result was a marked improvement over the 16 ACH50 pre-renovation. We not only made the home more efficient, but also created a home that is sustainable, healthy, and well-designed.

Historic homes are available for bidding

There are many ways to approach adding. Every project is unique. There is no one-size fits all approach. There are two options when working with an historic home, one located in a historic location or with a traditional facade. First, integrate the addition into existing architecture. The addition and the original home become one entity, with no visible differences between them. Our second approach, which we used with Adrienne and Trey’s home, is to create purposeful juxtaposition where each architectural element stands between existing and new.

We worked closely with the Craftsman-style homeowner to plan an addition. A modern addition can enhance and complement historical architecture by adding a confident presence. We didn’t want any changes made to the things that were working. We liked the front elevation despite the fact that much of the original house had been demolished. This was due to the historical nature of the neighborhood.

Modern meets Craftsman – This modern addition is both unexpected and purposeful. The open-concept interior is further separated by subtle variations in the ceiling height. The ceiling planes of the addition change as you move, drawing your eye upward to the views of downtown Austin. Photo by Casey Dunn

The homeowners’ goals were our guideline. We kept what was working and made changes to make it better. It was about preserving and adding to the house’s overall improvement. The main house was not altered, even though it was necessary to rebuild much of the structure. With the addition, square footage was also added.

The homeowners desired an open-concept interior. Older homes have more traditional floor plans that are divided and marked with walls. The interior had to be reframed so that the floor plan could be opened to accommodate the family’s lifestyle. Trey and Adrienne did not want a great room in their small home.

Using architectural features, the kitchen, dining area, and living rooms are visually separated. The kitchen’s light well is an indication of division. It allows for natural light to flood the area, which amplifies it. The ceiling planes can be varied to create subtle separation between spaces. These cues can be used to effectively identify areas within the home, without affecting sightlines. Hugh Jefferson Randolph Architects principal.

The right windows at the right time

Any 100-year-old house can be upgraded to improve its R-value and increase its curb appeal. Triple-pane windows were chosen for their superior performance but we had different stylistic requirements. We ended up mixing and matching three styles of Marvin windows. The traditional-style windows preserve the historic façade, while the moderner style matches the design of the new addition to the home’s back. We chose a less expensive option that was not as visible, but still provided excellent performance.

The new windows were kept the same size as the originals and placed in the same place. All sills are aligned between the old windows and the new ones. Contemporary additions feature floor-to-ceiling windows with brake-metal trim made from thin metal sheets bent to fit around the window. This minimalist trim design gives the downtown view a modern look and maximizes downtown views.

Modern aesthetic– The new addition is reflected in the windows at the back of the house. These modern-style windows capture some of downtown Austin’s skyline. (Marvin Signature Modern). Photo by Casey Dunn.

Historical accuracy– This Craftsman-style home was located in a historic area and required wood-clad windows for its historical façade. (Marvin Signature Ultimate)

Balance between performance and value– Fiberglass was used for areas such as the loft or bathroom that are not easily visible. This ensured high performance and a budget-friendly design. (Marvin Elevate)

This article will provide details about the HVAC system in this house.

Photos by Leonid Furmansky except where otherwise noted. Drawings by Christopher Mills.

Did you miss our previous article…
https://tophouseimprovement.com/design/fine-homebuilding-is-energy-efficient-at-multiple-levels/