9 Steps to Building an Eco-Friendly Addition

Master carpenter creates an energy-smart garage and workloft to accommodate two home businesses and the family car.

The Wilson family hopes a Deep Energy Retrofit (DER) of their 70-year-old home will drastically reduce their power bills. As part of the major project, they have to demolish their old garage, plagued with energy-wasting leaks, and build a new energy efficient one.

Step #1: Demolish the existing structure

Jeff recycled all of the aluminum siding, transferred some usable lumber to a farm house he owns out in the country, and sent windows and doors to a construction resale firm in town. "Regrettably, we had to put the rest in a dumpster and send it to a landfill," Jeff says.

This is a reality for many homeowners in communities where construction-waste recycling is not the norm. "I encourage people to check their local construction waste situation. It's different everywhere," Jeff says. "Doesn't pay to truck the stuff hundreds of miles to recycle it, though."

Step #2: Raise the roof

Jeff built up — then out. He began by raising the roof of the home and maintaining that roof pitch in the new addition. That created more headroom to what was a cramped upstairs office space above his garage (the old door was only four feet tall). Now, the space has lofty 13-foot ceilings.

Step #3: Lay the foundation

The old cement garage foundation was heaving and cracked, so it had to be replaced.

Step #4: Insulate the foundation

The new foundation features a floating cement slab, which means insulation is applied before concrete is poured. This prevents cold air from seeping up from the ground into the building — a key feature since Jeff and his wife, Sherri, are hoping to keep the garage/office space warmed at 55 degrees so they can work there (wearing sweaters) in the winter.

Step #5: Build the walls

Engineered lumber leaves a light carbon footprint because it is harvested from small-diameter, fast-regenerating trees, Jeff explains. That means no razing grand rainforests to make construction wood.

"Some of the products even come from what might have been considered waste products in years past," he adds. Plus, the Louisiana Pacific brand product Jeff chose is bonded with safe resins that contain no formaldehyde.

Step #6: Make room for windows and doors

Window and door holes are cut to accommodate the efficiency gold standard: triple-pane glass windows. The Clopay garage door Wilson installed cost $2,000, but its efficiency rating, or R-value, is R-19 — the best he could find. Others he looked at were less expensive, but their R values were 4 to 6.

Step #7: Build the second level

In order to make room for a second level with a 13-foot ceiling, Jeff had to raise the roof angle of the back of the existing house.

Step #8: Add insulation

Jeff's team insulates the walls, applying Spray-It Green foam between joists. The exterior is sealed with standard house wrap.

Step #9: Install siding

Jeff applies SmartSide engineered wood siding, which is made from small-diameter, rapidly regenerating trees. This makes it an eco-friendly lumber—plus, it's treated with nontoxic resins, and it comes ready to paint. The standard alternative is fiber-cement siding, which creates a lot of harmful silica-laden dust when cut, Jeff explains. "Having worked with fiber-cement for years, it's nice to be cutting real wood, not worrying about the silica dust," he says. "Also, SmartSide is lighter, less brittle and stronger than fiber-cement — all things I appreciate since I'm the one hanging the stuff!"