What is a Backyard Cottage (or ADU or DADU)?

An Accessory Dwelling Unit (ADU) or Detached ADU (DADU) is another dwelling unit or small house in or next to the primary house and on the same lot.  It’s also commonly called a mother-in-law, granny flat or backyard cottage.

What is it used for?

It can be used as a rental income property, guest house, home office, yoga or art studio, hobby space, aging-in-place, extended family, post-college children, or perhaps several of these things over time.  It can also be used as a single family house, primary residence or summer cabin.

Why work with Backyard Box?

  • – Design is already done (save time and money, start right away)
  • Turnkey – One contact from start to finish (we manage the entire process for you)
  • – Experts in Small & Sustainable Design

Where are they currently available?

Expanded distribution now includes the West Region: Washington, Oregon, California, British Columbia, Nevada, Idaho, Montana & Wyoming.

How much does a backyard cottage cost?

Backyard Box has designed and priced all backyard cottage models so you know the cost up front.  Utility hook-ups and foundations vary per lot, so those fees are additional.  The Match Box starts at $79,500 – affordable for an in-city house!  Prices for the larger models start around $86,000 and the largest unit with the LUXE finish package, foundation, utilities and a couple accessories would be around $150,000. Contact us for more info on pricing.

Is it sustainable and environmentally friendly?

Small homes are inherently more eco-friendly, and every Backyard Box incorporates sustainable features, such as: pre-wired for solar, super-insulated walls and windows, non-toxic paints, and rain screen siding.

What is Passive House?

Passive House is a European concept that has gained popularity in the US due to rising energy costs and climate change awareness. It is an advanced construction methodology that reduces energy use by 70-80% without sacrificing all the normal stuff you need in your home. Our designs are made to be built to Passive House standards and are designed by PH certified consultants.  Why? It’s the future of building, and it’s possible today, so why build to yesterday’s standards.

Can I have one in my backyard?

If you live in a single family zone in Seattle, on a minimum 4000 square foot lot, and meet a few other qualifiers, then yes. Our designs are made to fit on most city lots.  Other cities around the region allow them as well. Contact us for more details on your situation.  It also works as a primary residence most anywhere in north America.

How much does it rent for?

As a rental income property, you’ll be able to charge the prevailing rent for your neighborhood for a new small house, in the range of $900 to $1,500 per month in urban areas, and you usually include utilities (utility costs will be minimal on such efficient units).  That’s an extra ten to eighteen thousand dollars a year in passive income.

What if I live outside Seattle – can I still build one?

Many cities allow Backyard Cottages in single family zones, and have for years: Clyde Hill, Issaquah, Kirkland, Mercer Island, Shoreline, Newcastle, Redmond, parts of unincorporated King County, Woodinville, Yarrow Point, and Portland, OR to name a few. Seattle passed the ordinance in late 2009.  Santa Cruz has a strong backyard cottage program.  We service the entire West Coast.

Can it be larger than 800 square feet?

Your backyard cottage may be able to exceed 800 SF. Any portion below grade does not count in the area calculation. It depends on your site.

What are typical uses?

Typical uses include work space, studio, retreat, aging-in-place, recent graduates, young families, multi-generational families, snowbirds, or rental income. You could use it as an office to escape noisy home activities, and then later on for the kids to occupy before they’re financially stable, and even live there yourself, with the main house occupied by the next generation to raise their family.

What is Make it a Smart Box?

Make it a Smart Box is an option to upgrade the sustainable features to incorporate solar H20 & PV solar panels and a smart home dashboard to monitor energy use in real-time (just like Bill Gates’s house!).

Can it be used as a working studio?

It can be used for just about anything – fix up old motorcycles, bronze casting, indoor botanical garden, you name it –overhead garage doors can be optionally integrated for easier project access.

How could I finance this?

We can direct you to financing options – the most common would be a Home Equity Line of Credit based on the value of your primary residence, or even a Custom Construction Loan (yes, we have a lender for ADUs in King County). Contact us for more details on financing.

What about parking?

Some cities require an off-street parking space for backyard cottages.   Seattle requires 1 off-street parking place, but there are some exceptions.

What’s included with pricing?

Pricing includes everything except foundation and utility hookups, as that will vary depending on your lot. We also leave appliances up to you since personal tastes vary widely. Our base models come complete with high-end durability and sustainable features including rain screen siding, solar PV pre-wiring, standing seam metal roof, and the most energy efficient designs in the world.

How much does the foundation cost?

The cost of the foundation can vary depending on your lot slope, soils and other factors, so we can’t estimate the cost reliably.  It may be $1,500 on up to thousands if you have a steep site.

How much are appliances?

A decent appliance package starts at three thousand dollars total including laundry, but it goes up from there.

Can I match the siding to my existing house?

Yes, that’s pretty typical for backyard cottages, and some jurisdictions may even require it.

Just these designs or can I do custom?

Yes, Custom Box is an option whether you want to match your home’s finishes on the exterior, or start a design from scratch. Backyard Boxes can be customized to suit your individual needs.

How do you meet Passive House standards?

Since the Backyard Box designs are not site specific, we had to make some assumptions to do the initial Passive House energy modeling, to ensure that they can meet the PH Standard. Depending on your specific site, and its orientation, solar access, surrounding buildings, trees, etc., we may have to make some adjustments to the Passive House model for your Backyard Box. If architectural features have to be added (e.g. more windows to increase solar gain), or the mechanical system adjusted, to maintain Passive House Certification for your lot,  you can opt to add these at an additional cost. But rest assured, whether your Box meets the Passive House Standard or not, it will be an ultra-energy efficient structure.