Winter Sun Design: An Urban Backyard Office

Working in a home office has many advantages, like no commuting, low overhead, flexible hours, and spending more time with the family. However having a 3 yr. old and a 5 yr. old playing directly above a basement office can be distracting. This was the motivation for an 11' x 16' office addition onto the back of the client's existing 11' x 18' garage. Being sensitive to and informed on the impacts of building on our environment the client chose to use as many environmentally friendly materials and systems as the budget allowed. He chose to be his own general contractor in order to save money, and have total control over the project. This proved to be a major commitment that happily he was mostly prepared for.

The foundation and hot water radiant slab contain 25% fly ash which increases strength, extends the workability, and replaces energy intensive cement with a waste product. The slower curing was helpful as the slab was poured on a hot day and had to be brushed and washed repeatedly to expose the 3/8" aggregate that is the finish floor. It was finished with Thompson's water based concrete sealer. The floor has 250' of Kitec plastic tubing in a serpentine pattern tied to 6" x 6" x #10 wire mesh on plastic chairs at the 4" slab's mid point. The water is in a closed loop and heated by a 1,300 watt wall mounted electric heater. Insulation is 2" of expanded polystyrene (R-10) under the slab and around the perimeter. This sits on 6 mil poly, 3" of sand and 5" of recycled crushed concrete from Pacific Topsoils. A 3" galv. pipe goes from the finish floor to the bottom of the gravel base to monitor ground water. It is also insulated from the slab.

The framing lumber consists of 2 x 6's @ 2' o.c. and 1/2" CDX plywood from Collins Pine Co.'s SCS Certified Well Managed Forests and was bought through The Environmental Home Center. Rafters and ceiling joists line up with the studs so a single top plate could be used. Recycled shredded newspaper treated with low toxic boron was blown into the walls to give R-20. Fiberbond recycled cellulose/gypsum board was the preferred wallboard material but the minimum quantity available is 32 sheets. Insul-safe III fiberglass was chosen for the attic because of it's permanent loft and no formaldehyde, no-itch characteristics.

Windows are Insulate lo-e, argon, (U=.31) and are cased and trimmed with wood salvaged from a previous project. The trim and walls are painted with Best Paints low toxic, no solvents, primer and paint. Base trim is beveled fir siding scraps covering 1" polyiso board to insulate it from the concrete stemwall. It is sealed with OS/Clear natural oil, wax based finish containing no preservatives or biocides. Redwood shingles salvaged from old growth stumps by Amarant were used for the siding and clear coated.

Passive solar heating is precluded by a large cedar tree. Compact fluorescent overhead lights are controlled by individual switches. Multiple phone lines and co-ax cable were buried in the trench with the electrical for a future owner's anticipated needs. Sheet rock was recycled at GTS in Kirkland. Unfinished wood scraps were turned into mulch at Pacific Topsoils and bent nails were recycled at the curbside. Only the composition roofing scraps, painted trim scraps and the pressure treated sill plate scraps were sent to the landfill. Even the excess concrete from the 2 pours was slopped into egg cartons to be used as pavers. Knowing that you've done all you can to reduce the environmental impacts of your new building makes working in a new office even more satisfying. And long after the increased costs and troubles are forgotten the lighter footprint and feeling of satisfaction live on.

- Ecobuilding Times, Fall 1999