n02 City Cabins by Martha Rose Construction

Good News, Congratulations to Martha Rose Construction, who's 5-Star Built Green project just recently SOLD!  You can visit the builder during the Tour at Greenhome Solutions to find out about the green features of City Cabins, her upcoming projects and learn about her green building approach, style, and commitment.

The solution: provide a next-generation home utilizing cutting edge building technology and energy efficient innovations.

The two townhomes, currently listed for sale, offer sweeping views of Fisherman’s Terminal and beyond to the Olympics. The homes feature hi-performance equipment, appliances and building techniques not found in spec-home building.

By touring the multi-certified homes you will be able to learn about the individual components and systems that when combined together make a healthier, more efficient, durable and sustainable home.

One of the goals of the project was to build a sustainable home that could accommodate changes in lifestyles and inhabitants living requirements by offering flexible living areas and design features to accommodate everyone. 

The original 1952 side by side duplex had fallen into such disrepair, that it made our decision to build a new structure an easy one. To avoid ground disturbance though, we deconstructed the entire structure by hand, pulling nails and loosening mortar from bricks, so that the original footprint and foundation could be reused. Over 4,000 board feet of lumber were re-used from the old building and all of the bricks became pervious surfaces on site.

Designing for passive solar was easy, however making the home accessible for changing lifestyle needs presented a huge challenge. We took advantage of the higher alley elevation and made the primary living space on the top floor with an almost level entry from the garage.

The best views are from the living room and the access to the bedrooms is down a wide stair that has been pre-wired for a chair lift. The master bedroom on the middle floor utilizes an ADA accessible shower pan and hand forged towel bars double as grab bars. An on-grade brick patio outside the front door provides the afternoon sunny spot for view watching and visiting with neighbors, while the back porches provide an outdoor sitting spot out of the rain.

Master Vanity	Sustainable Living Space	Stairs to upper levels

Other sustainable design and site features are: 550 sq ft of vegetated roofs, over 600 sq ft of pervious driveways, patios and walkways, rainwater harvesting and Juniper wood timbers for landscaping. Designed by CB Anderson Architects.

Energy and Water Improvements at City Cabins:

The energy envelope was modeled by a Passive House consultant to provide a high bar to reach.

The old foundation is now structurally reinforced, with a new ground floor slab that is 30” higher and insulated with 6” of foam. New exterior wood walls are built as staggered stud 2x4’s with a 2x8 double plate and hollow headers. One inch of closed cell foam is placed under the exterior cdx plywood.

New roof trusses have twenty inch energy heels and quadruple paned windows are installed in a manner that reduces thermal bridging. All window frames and doors are insulated fiberglass.  Here are the envelope statistics we ended up with:

• Under floor slab  -  R-30
• Under wood framed floor  - R-50
• Exterior walls  - R-31
• Windows  - R-6.5  U-value 0.15
• Exterior Doors  - R-4
• Main attic  - R-75
• Bay window ceiling  - R-60

For water conservation, we looked at every way we could help owners save on their water and sewer bills. Flow charts for all of the fixtures influenced choices as well as style. We picked the well engineered Danze shower heads (1.5gpm), the Moen Kingsley faucets (.5gpm), the Vigo kitchen faucet (1.6gpm) and left the water consuming garbage disposal out.

A central plumbing core was designed into the homes to allow quick delivery of hot water, efficient appliances were chosen and finally, a 300 gallon rain barrel is provided for each owner to water landscaping.

Materials & Indoor Air Quality at City Cabins:

We take many measures to insure high indoor air quality. One is to use only pure healthy ingredients. This step cannot be underestimated! All framing and finish lumber is unprocessed real wood and plywood with non-formaldehyde glues, including no pressure treated lumber indoors. Materials, mastics and finishes all are Low and No VOC.

We take great pains to keep driving rain and wind outside where it belongs. Larger overhangs, double layers of one hour paper, stainless window sill pans and proper flashings all work together to accomplish this goal. Underground drainage was also installed to carry away below grade moisture.

With the installation of a continuously running high efficiency HRV system and merv12 filter, conditioned fresh air is delivered to the living room and all bedrooms while stale moist air is exhausted from the kitchen, laundry and bathrooms. Air within the home is completely refreshed every four hours without loss of heat.

Transportation Quotient of City Cabins:

This site has a Walk Score of 71, is just one block from a bus stop with 2 lines and is close to bicycle routes. We wired for an electric car and installed enough PV (1.9kw) on the roof to drive it 6,000 to 10,000 miles per year. The homes are close to Ballard, Fremont, Fisherman’s Terminal and the top of Queen Anne.

Innovations at City Cabins:

As we build to a deeper shade of green, each project has features that are new to us. After learning that gas in the home is unhealthy no matter how it is installed, we made a decision to have just one utility for power: electricity. That led to a shift in the choices we would normally make for equipment. Here’s a short summary:

• The Air Generate heat pump hot water heater. Using the team of experts approach, we came up with the ideal scenario to insure that one unit of energy in to the unit produces 3 units of heat out. We did several things to accomplish the goal. The unit is installed in an insulated conditioned crawl space with 1,000 cubic feet of air volume. The cold air produced by the HWH is ducted to the outdoors. A steady supply of 60+ degree air is delivered to the crawl space 24/7 from the heat recovery ventilation system. This unit is so efficient, it eliminates the need for solar hot water.
• Electrolux induction cooking range. Favored by chefs, it is 70% more efficient than gas. Made in USA.
• Mitzubishi 4-head minisplit heat pump that provides zonal heat if it is needed and cooling if that is needed.
• QuadraFire high-efficiency, EPA approved, wood burning stove just in case the power goes out and you need it. Made in eastern WA.