Energy Source Builder

Balloon Framing Key to This Advanced Energy Package

Simplicity makes Bill Reed’s houses affordable to build and efficient to heat and cool. Bill’s company, R&R Energy Resources, builds and manages rental housing in metropolitan Portland, Oregon. By striving for simplicity, his designs save labor and materials. He claims construction costs as low as $25 per sq. ft.

The building is framed with 2x6s spaced 24 inches on center. Trimmers and cripples are minimized by locating windows at existing studs. Corners are framed in a way that allows access for insulation. In the Northwest that’s known as “advanced framing,” but there is one feature of the framing job that might be considered old-fashioned.

Balloon framing uses a single stud to frame the entire two story wall. That eliminates the rim joist. Instead, a let-in ledger supports the second floor joists. Batt insulation easily wraps around the ledger.

Bill’s designs are simple rectangles, usually with a porch attached. Heat loss is directly related to surface area. The building’s rectangular shape is inherently energy efficient, because it encloses a large volume with a relatively small surface area. Design simplicity makes it easy for workers to do a good insulating job. Fewer odd sized wall cavities means less cutting and fitting batt insulation. Bill’s crew, who are paid by the hour, aren’t quite as rushed as insulation installers working for a flat bid. Bill’s crew also installs 3/4 in. urethane foam sheathing. That boosts the insulating value of the wall to R-24.4.

A blower door test of the house showed the air leakage rate almost low enough to qualify for the “advanced air sealing” designation. “I wasn’t trying to make it super-tight,” says Bill. “The way we do things just naturally makes the house tight.” Those things include: Drywall covers the entire wall, because it’s hung on the exterior walls before the interior walls are framed. All joints in the rigid insulation sheathing are taped. All joints and penetrations are caulked and foamed on the inside.

All these little details add up to a house that’s very efficient to build and efficient to operate.

balloon framing detailsfire blocking detail

This article appeared in Energy Source Builder #27, June 1993
©Copyright 1993 Iris Communications, Inc.