A Wood-Frame Retrofit, Wrapped in Wood Insulation

A Wood-Frame Retrofit, Wrapped in Wood Insulation

Sidney Beaumont is an Emmy-award-winning documentary filmmaker, 475 investor, and Passive House enthusiast. His films are of special interest to those concerned with climate and environment, including: From the Ashes and Paris to Pittsburgh. His latest labor of love, however, involves retrofitting his Seattle home following Passive House guidelines. Sidney has studied high-performance building for a number of years and is excited to have a project of his own – a deep-energy retrofit where he is working to maximize performance, durability, and health while minimizing the lifecycle carbon impacts, in part, by selecting carbon storing insulation options.

Sidney first came across 475 when working on a retrofit project back when he lived in Brooklyn, New York. He became intrigued by 475’s building science and product lines and had a particular interest in GUTEX insulation. While exercising his knowledge of Passive House, Sidney’s focus is really about rethinking the way we way build. He cites legislation in New York and California, putting building regulations on a path towards lowering carbon emissions, as an inspiration for making buildings better and subsequently a means to “electrifying the economy.” In particular, Sidney believes it is important to focus on old buildings, saying that with millions of old houses in the U.S. alone, it’s imperative to focus on taking stock of and renovating these homes, going a step deeper into the “sustainable” aspect of Passive House building. He notes that with our limited timeline for reducing carbon emissions to meet our climate goals and avert escalating impacts from climate change, there are also real benefits to using carbon-storing insulation such as Gutex rather than toxic and high carbon impact conventional options.

Kicking Things Off

Sidney and his wife Jessica are starting with a mostly original 1907 wood framed house in the Leschi neighborhood of Seattle, Washington. They bought the home in March of 2019 and expect to move-in, in late October, 2019. To kickstart the project, they enlisted the help of local design-build firm Batt+Lear, an experienced and devoted sustainable building practitioner, who designed the project and collaborated on the plan of attack for the retrofit.

In order to prepare for the retrofit, Sidney read and referred to the Smart Enclosure Wood Retrofit details. Batt+Lear and Sidney also worked very closely with our Western Regional Manager, Lucas Johnson, who is a building scientist and construction management expert. Sidney can not be more enthusiastic about the Batt+Lear team: Jason Lear (Architect-Principal), Walter Goodwin (Construction Principle), Nick Goodwin (Project Manager), and Jan Kunasangeamporn (Designer).

A Unique (and Non-Invasive) Approach to Insulation

In the planning process, it was decided they would install the insulation on the exterior of the home. They chose to use GUTEX THERMOSAFE WD insulation and covered it with SOLITEX MENTO 1000 to provide record setting airtightness, vapor drying potential, and waterproofing.

Being a 1907 wood frame retrofit, the corners of the home presented a tricky task for installation. However, they were able to get around this as GUTEX, being made from wood, can be cut into almost any shape with standard carpentry tools. The team was able to cut a 90 degree channel into the edge of the boards, allowing the GUTEX to seamlessly create a thermal break between a 2x2 window buck and the flange of the window. In addition, between the window rough openings, there were areas that required cutting the GUTEX boards at 30 degrees so that two pieces come flush together creating a continuous board. After roughly two decades on the leading edge of green building, Lucas has never seen another insulation that can be cut so cleanly and accurately while still maintaining strength.

The GUTEX was installed with a minimum of fasteners per board. This is because after the GUTEX was placed, the home was wrapped with MENTO 1000, which was applied with screws penetrating all the way through the GUTEX and into the siding, and limited the number of fasteners, and minimizing the chance of thermal bridging.

Lucas Johnson, referred to installing exterior installation on a 1907 home as a “black belt level retrofit.” Lucas noted that not only will this insulation help the home reach near Passive House standards, but GUTEX is also carbon sequestering, helping make this home renovation a climate solution right away. With an R-Value of 3.6 per inch, the raw material for all GUTEX insulation boards comes from wood that is harvested and grown using sustainable forestry management practices. GUTEX THERMOSAFE is a highly compression resistant wood fiberboard that can be used in facades and fully sheathed roofs in rainscreen application when protected by ProClima WRB or roof underlayment. It is also vapor open, allowing safe drying of the thermal envelope. In this case the team chose to use SOLITEX MENTO 1000 for the WRB as it is a highly waterproof 3-layer, monolithic, air-tight vapor-permeable house wrap.


Taking the exterior approach with GUTEX was also beneficial when it came time to install the windows. The Batt+Lear team decided to cut ⅛” thick slices of GUTEX to use as insulation between the rough opening and window frame instead of backer rod foam. After installing GUTEX around the windows, it was then detailed and air sealed with two different products in different locations. Lucas also demonstrated how to seal doors and windows with TESCON PROFECT tape, and was found to be both extremely easy to work with and effective. This Pro Clima window integration solution created a 100+ year, red list free, Passive House-level window integration. Pro Clima system products used throughout the home included VISCONN, TESCON VANA and TESCON PROFECT.

For the windows, Alpen Windows were carefully selected and installed. Sidney shared his positive experience working with Alpen and the company’s representative, Leah Primrose. There are certain aspects he loved about the windows, including the fact that they are fiberglass reinforced and and therefore less vulnerable to expansion or contraction, and that the swinging European style windows are designed to imitate the look of a double-hung window without being double-hung (because true double-hung windows, of course, are low performing). Alpen Windows are recommended for use with Pro Clima airsealing tapes, and in this case, GUTEX too!


On the interior, Sidney’s team installed the INTELLO PLUS airtight membrane and smart vapor control system. Sidney said that the INTELLO was particularly useful and easy to work with, especially in the attic where it can be hard to airseal.

To ‘Wrap’ Things Up

With this retrofit, Sidney hopes to create a case study for how to approach deep energy retrofits. He wants to show that Passive House and Net Zero building can be cost effective and the process of retrofitting does not need to disrupt day-to-day activities of homeowners. By putting the insulation outboard, Sidney has shown how to limit the interference of the construction process to occupants. Sidney will be moving into this home in October while the renovation continues.

We’re excited to announce that Sidney has been taking video of the process. Stay tuned for more to come, and join us during our April 16th webinar covering concepts, challenges and details involved in making this low-carbon retrofit a reality.