Seattle's Backyard Cottages – Going Green and Beyond

In a previous post, we gave you the low down on Seattle’s new ordinances regarding Backyard Cottages, now we want to explore whose building them and how the process works.

DADU designed by Skylab Architecture – Built by Method Homes

Now that backyard cottages are zoned citywide, they’re beginning to pop up all over the place, and in a plethora of delightful flavors. While they will inherently be as unique as the folks designing and building them, one very prominent theme is ‘going green’. Attendees of this year’s Seattle Home Show, February 20th-28th, will get an up close and personal look at a number of cottage designs including FabCab’s new line of pre-fabricated, environmentally-friendly, timber frame cottages, fully loaded with innovative materials and products. You can also check out this City Stream video of a cottage built in Columbia City.

The Design Process: How Do I Get Started?

The process starts by either hiring a design/build firm who can also help you navigate the permitting process, or by taking the Do-It-Yourself approach. The Department of Planning provides a number of prototype cottage designs, which can be adapted to your site. Site-specific considerations include – size, location on your property, site disturbance, privacy from neighbors and main house, location of utility connections, and the needs of future occupants. The minimum lot size required to build an 800 square foot Backyard Cottage in Seattle is 4,000 square feet. The permitting process itself is relatively fast, and can happen within a month. There is no survey required, but the DPD will conduct site inspections before and after construction begins. The DPD provides a comprehensive Guide to Planning a Backyard Cottage.

Backyard Cottages require a visit to the Department of Planning

Choosing Your Approach

Dana and John Stream decided to take the DIY approach and closed last month on a single-family home in Maple Leaf, with a lot which will allow them to design, build and ultimately live in a DADU with their two children. They believe families can live in comfort and grace in small spaces, and plan to put their money were their mouths are by living in their own 2BR/1.5BA DADU for at least a year.

John & Dana – Embarking on a DADU Journey

John is a building biologist and a sustainable development specialist, so innovation and efficiency are his specialties. His designs link science, art, and the spirit, by going beyond the mere use of green materials. This includes the elimination of metals and electrical fields in the house to reduce harmful radiation, the customization of built-in beds, fold-down desks, and a collapsible dining table to increase usable space, and the use of healthy materials and finishes for optimized indoor air quality.

If designing and building are not your forte, another option is prefabrication. Built in the controlled environment of a modern factory, today’s prefabs excel in quality, design, impact on the environment and construction time. Prefabs can be attached to the foundation, hooked-up to utilities, and have their interiors fully finished, all within days of delivery. Seattle-based Method Homes builds prefabs to the specifications of architect/designers and DIY homeowners in about 1-2 months, start to finish.

Traditional builders are also now offering their own lines of backyard cottages. Bob Scott of the Little Building Company builds what he likes to call a dadugreen, a green detached accessory dwelling unit. He offers custom DADU construction with over 30 years experience in the building industry. When site planning, Bob Scott says the best lots for building DADUs on are corner lots, with a close second being those with alley access behind. This is because of the City’s requirement that their be a dedicated off-street parking spot for and access to the DADU.

What is a Backyard Cottage Going to Cost?

The very big question on everyone’s mind is cost. Size is limited to 800 square feet, so what might the typical cost per square foot be?

Bob Scott quoted us $100/square foot for his dadugreen, depending on how fancy it gets of course. This, he said, has a lot to do with the fact that he’s simply using fewer building materials. In a typical dadugreen you’ll have two stories of mostly open space and there is no central heating system. In other words, this is not a miniature house with a multitude of interior walls/rooms and expensive equipment needed to heat it all. The foundations are also hand dug, because the footprint is small and the concrete posts only go 12″-18″ into the ground. Additionally, he finds that homeowners themselves like to contribute sweat equity by finishing out the painting, landscaping and such, which brings costs down.

Dana and John have calculated that their building costs will run $120/sf, and $180/sf with the additional custom furnishings. Method Homes provides a general range of $100-200/sf for a DADU, which is again dependent on what finishes you choose. The DPD has published some great examples of Backyard Cottages built citywide and with associated costs.

What Makes a DADU Green?

The obvious answer in our minds being size, because building ‘McDadus’ is simply not an option. Inherent to the small size is the need to maximize space, which means careful planning and good design. In other words, Backyard Cottage code is somewhat like a ‘prescription’ for building green, and they can more affordably be built to the highest levels of efficiency, with materials that are healthy, durable and sustainable.

DADU w/ Green Roof designed by Skylab Architecture

For Dana and John it’s more holistic – they hope to create a space of harmony, while also having the option of additional rental income. They also see this as contributing to a more sustainable community, which was also a major driver behind the expansion of the Backyard Cottage code in Seattle. Backyard cottages offer a way to downsize while living close to family and staying in the same neighborhood. They offer flexibility for extended family or friends, or an opportunity to invest in your own property while providing an affordable housing alternative.

In the coming months, we are going to tag along as Dana and John build their new DADU – so stay tuned for updates, videos and more. And as always, if you have any questions feel free to give us a call any time!