Greenwood resident Kate Lichtenstein contacted us last spring to help her design a backyard studio / guest house for her modest 650 square foot 1920's one bedroom home (shown above). While the home's scale fits nicely with Kate's desire to have a simple and ecologically responsible lifestyle it falls a little short when it comes to a rough and ready workshop space for art, bicycle repair, ski tuning and building projects. Kate's home also lacks the space for a home office / guest room - something that she would like to integrate into the new structure.

Our initial goal was to have her project under construction by late summer 2009 but we were unable to get the project off the ground by that time. In hindsight, the stalling of the project turned out to be a stroke of luck...

In March of 2009 Seattle Mayor Greg Nickels proposed legislation that would allow Seattle homeowners to construct backyard cottages on their property. The legislation was reviewed and ultimately passed by the Seattle city council on November 2nd 2009 (with a 9 to 0 vote too! Kudos to Seattle voters for electing progressive urbanists for city council members!).

For Kate the ordinance has opened up new possibilities for a structure that can both accommodate her current needs and provide a potential source of income as a rental unit if her finances ever fall on hard times. Besides allowing for a legal detached rental unit the ordinance also allows for the construction of a two story structure – an arrangement that will work well for Kate’s needs and will help to preserve the spaciousness of her backyard.

Kate is planning to build with a mind toward sustainability and has a special interest in using recycled building materials whenever possible (she is, at this time, planning to write a parallel blog on the topic of recycled building materials). For us at CAST architecture Kate's project is an exciting chance to test out the new backyard cottage ordinance and work with a client who is committed to building green. We see her project as an excellent opportunity to provide the general public with information about the process of designing and building a backyard cottage in Seattle. Kate and her partner Ric Cochrane are always game for an adventure and have graciously agreed to allow us to share their experience with you. To that end, we are planning to blog about Kate's project as we travel through the design and construction process. Please subscribe to our feed if you would like to follow along in future posts…

This product isn't new, but new to us:  sheep wool insulation. Sheep wool insulation has some advantages over other forms of insulation, especially fiberglass batts.  It stays lofted, retains R-value even when there is moisture penetration.  It installs like fiberglass batts, but there are no masks, no off gassing, no itchiness.  Plus the product is all natural, and there aren't the environmental impacts of making fiberglass.

There are a couple big downsides:

1--this is not a local product, and there are carbon costs associated with bringing the insulation to our neck of the woods (although bringing together the elements to make fiberglass isn't carbon free either)

2--the cost is about $2.16 per sf, which is roughly three times the cost of fiberglass, or 50% more than spray foam.