Just north of the entrance to Seward Park, directly across from the water’s edge resides The Lake House. Built in 1919, the historical home was designed by renowned California-raised architect, Edwin Ivey, in the Spanish Eclectic style reminiscent of the homes found in Pasadena. A street-to-street lot, prime location, and a magical facade sparked the interest of the founders of Dwell Development (Dwell), Abbey and Anthony Maschmedt. For them, it was love at first sight. Their challenge was taking the sustainability practices they employ in new homes and implementing them in a home over a century old. It was a challenge they fully embraced when they devised their plan for The Lake House 2.0.

Dwell set out to do something extraordinary with this amazing parcel located on Lake Washington Boulevard South. Their job was to solve the puzzle of taking advantage of a unique development opportunity while maintaining the original integrity of the existing home—with a little over 20,000 square feet there were endless possibilities.

Fortunately, the existing home sat on the front portion of the lot with a massive grass front yard facing the lake. Behind the house, there was an existing carriage garage, that was originally intended for a vehicle and a caretaker. Beyond the garage was a large, landscaped yard that fronted 57th Avenue South. The site being street to street, provided room for development and design.

In most cases, similarly zoned sites would see the existing house demolished, then subdivided to create 3 new approximately 7,000-square-foot parcels, with 3 new single-family homes built. However, the Lake House was architecturally significant, and while it would take a lot of work to modernize it for another century of use, the Maschmedts knew that preservation had to be the goal. Then again part of modernization is also using resources more wisely, and land and housing are finite resources. So they had to also re-envision the site to maximize such valuable resources. Ultimately, they decided to preserve the Lake House with a new DADU and office, then subdividing it into two parcels to build a new single family home with an accessory dwelling unit. This increased the housing capacity of the site to 4 housing units.

Curve balls are expected when planning a project like this, but the Covid-19 pandemic presented unique challenges when it came to design decisions. During the pandemic Seattle Parks, which owns Lake Washington Boulevard, had decided to shut down the boulevard regularly to accommodate pedestrians, bikes, and strollers. Continual access from the back of the Lake House needed to be maintained, because there was a looming threat of a permanent shutdown of the boulevard to cars.

The biggest obstacle of the project would be updating the existing single-family home. Though Dwell is well-versed in sustainable new construction, historical restoration was not on their resume yet. They needed to balance preserving the amazing home, saving it from the landfill and maintaining its original charm and character, while updating and modernizing it to assure it met all the expected energy efficiency of a Dwell Development home. Ultimately, the goal was for The Lake House 2.0 to be Dwell’s first Net Zero Energy renovation.

Inclusive of the down-to-the-studs renovation of the existing home, the existing carriage garage was demolished and replaced with their first Net Zero Energy DADU. The DADU includes a 2-car garage that is accessed off of 57th Avenue South and serves as the new Dwell Development office headquarters. In addition, another first for Dwell, a Net Zero Energy Ready 5-Star Built Green single-family home with a legal AADU was built on the remaining portion of the parcel in the rear overlooking the main house and the lake.

Dwell applied all their standard, tried and true, sustainable systems and practices to the project. The existing house was stripped down to the studs, and a 1,500 sq ft addition was added to the back. Originally built with no insulation, they knew that proper insulation would be critical. After removing all the plaster and lathe, they added blown-in cellulose insulation. The exterior was also clad in a rain-screen Portland Cement Stucco, a cladding very unusual for the Northwest. The new stucco on the addition would need to match perfectly to blend old and new. No stone was left unturned in preservation. Existing millwork, windows, light fixtures, and doors were removed, stored, and eventually returned to their rooms. Their goal was to avoid waste and reuse as much of it as possible.

Heating and cooling and air quality are essential to a sustainable home. Anthony and Abbey called on trusted manufacturers, because they knew they couldn’t do it all alone. Partnerships were essential to the project. Mitsubishi and Panasonic lent Dwell their HVAC and fresh air consultants to design a new type of state-of-the-art heating/cooling and fresh air system. They also donated all the equipment towards this never-used-before system. The HVAC system features an ERV integrated into the ducted heat pump air handler to provide triple filtration and air scrubbing, maintaining premium fresh air and thermal comfort throughout the home.

The Lake House and its DADU is designed for a 16kW solar PV array that provides it a net positive energy balance. The solar PV will not only power the home and DADU, but also the swimming pool and an electric vehicle. The single family home is solar PV ready and includes two level II charging outlets for EVs.

The final results are something Dwell Development is very proud of. A feather in their cap and a homage to sustainability. Having completed a 5-Star Net Zero Energy Certified Built Green renovation, a 5-Star Net Zero Energy Certified Built DADU, and a 5-Star Built Green Net Zero Energy Ready Single-Family Residence with AADU simultaneously in one project, Anthony and Abbey Maschmedt of Dwell Development believe anything is possible when you set your mind to it. Lake House 2.0 is ready to roll into the next one hundred years.

Author: Nina Olivier, Built Green Coordinator

Spring is upon us in the Pacific Northwest and for many it also marks the beginning of allergy season, which affects up to 30% of the US population and 40% of US children. The CDC expects that climate change will lead to both higher pollen concentrations and longer pollen seasons. However, climate change is not the only contributing factor to the increase in pollen counts, it is only exasperating a situation caused by generations of selective breeding and prejudicial landscaping decisions.

All plants contain male sex organs called stamens and female sex organs called pistils. Pollen is dispersed from male stamens and captured by the female pistil to create seeds for germination. While most plant species are monoecious and include both male and female reproductive organs, many plant species are dioecious with individuals that make only pollen or only seeds. In fact, most of the tree species used for street trees in urban settings are male dioecious trees.   

Ironically, if city planners and landscapers had prioritized female trees and plants, in the same way as male plants, neither pollen nor unwanted seeds or fruit would cause issues. Female plants do not produce fruits or seeds if there are no males of the same species within 20 to 30 feet from its roots. He goes on to explain that allergy-reducing landscaping includes not just understanding the importance of plant sex, but also encouraging pollinators and eliminating mold growth that can occur in hedges and compost piles.

From his observations Ogren now believes that the reason so many butterflies are disappearing is because the [female] nectar-producing trees were a major food source. "And they are disappearing because they are being replaced by the [male] pollen-producing trees," said Ogren. Planting native species of plants supports native pollinators with the foods they are accustomed to. Furthermore, non-native plants may become stressed since they are not used to the climate, and therefore, may produce more pollen. To guide cities to plant less allergenic trees, Ogren developed the Ogren Plant Allergy Scale (OPALS). The scale rates plants from 1–10 based on their allergy potential.

Grass is a major pollen producer, thus, to reduce allergy triggering pollen, the Asthma Society recommends mowing grasses regularly before it flowers. Better Home and Gardens recommends planting species that are pollinated by bees; the pollen of these species is heavier and sticky and therefore stays on the bees rather than floating around in the air. In addition, mold growth in hedges and compost can also affect allergies. To discourage mold spores Ogren recommends keeping hedges trimmed regularly to increase air flow between the branches, keeping compost bins covered, and turning compost piles about every 2 to 4 weeks.

Local pollen counts can be tracked and monitored through the US Air Quality Index. The University of Illinois Extension recommends reducing exposure to plants that flare up allergens through wearing long sleeved shirts, long pants, gloves, hat, and even a mask while gardening.

Increases in carbon emissions and climatic changes in weather patterns are causing more people around the world to experience negative health effects from pollen and other outdoor allergens. According to the CDC, individuals with preexisting respiratory illnesses such as asthma, are more sensitive to pollen, which has been linked to increases in asthma attacks and associated medical costs that exceed $3 billion every year.  Decreasing the plants that contribute more pollen into the air can increase quality of life, especially for those already living in urban low-quality air zones.

The following is Allergic Living’s list of low-allergy options for your garden:

*Pictured below

Amelanchier lamarkii – Juneberry tree

Galanthus – Snowdrops

Purple phlox

ADUs are separate from the rest of the unit, allowing the owner to sublet or rent out the space. This approach tends to have lower costs and a quicker permitting process compared to larger, multifamily building types. Typically designed as a studio space with a kitchenette, ADUs also offer a method for affordable housing options, moderately increasing density, and the potential for aging in place.

With a high-efficiency gas tankless water heater powering the in-floor hydronic radiant heat, HyBrid was able to free up space along the walls to integrate built-in cabinetry and shelving to allow for extra storage. Additional energy savings come from LED lighting with dimmers throughout the units, R-23 walls, R-50 ceiling, and Energy Star exhaust fans. The combination of drought-tolerant plantings and all-pervious hardscaping allows for some water to recharge on-site and minimizes the need to water plants.

The project features materials that are local, long-lasting, harvested from rapidly renewable resources, and boasts certifications for indoor air quality. The building is clad in corrugated metal, which typically lasts longer, requires less maintenance, and is made in Washington state. Each unit has GreenGuard-certified flooring and paint, as well as CARB II cabinets to help maintain good indoor air quality. As a rapidly renewable resource, the bamboo flooring reduces the overall impact on natural resource availability. The building also used regionally-made cabinets, windows, framing lumber, and pavers. 

Built Green Highlights

Site and Water

• River rock retaining wall
• 100 percent pervious hardscaping
• Drought-tolerant plantings

Energy Efficiency

• Full in-floor hydronic radiant heat (with built-in recirculation)
• All LED lighting with dimmers
• Full slab insulation