An effective building envelope – the first floor, exterior walls, and roof – is a key element for an energy-efficient home. Advanced framing techniques increase efficiency and comfort while decreasing costs.
Most homes in Boise are framed with wood and wood loses or gains heat more quickly than insulation. In wood frame construction, studs, joists and rafters are placed at regular intervals throughout the building envelope. Standard construction practice places these framing members at 16 inches on center. The cavities formed by the framing members are filled with insulation. Standard construction practice at exterior corners and at the intersection of interior partitions and exterior walls creates pockets that are difficult or impossible to insulate and air seal. The unnecessary use of wood displaces insulation and degrades the thermal efficiency of the building envelope.
By eliminating unnecessary framing members, advanced framing increases the thermal resistance of the building envelope without compromising structural integrity. Advanced framing techniques include:
Wall studs, floor joist, and roof trusses are spaced 24 inches O.C. and aligned directly over top each other to promote thermally efficient walls, increase structural efficiency, reduce drywall cracking, and reduce wood waste.
2 X 6 – 24 inch o.c. exterior wall framing
2 x 6-inch studs set 24 inches apart instead of 2 x 4 inch studs set 16 inches apart are used to allow more room for insulation, reduce heat loss and heat gain due to thermal bridging through the studs, enhance the strength of the house, and reduce the overall amount of wood used in the construction of the home.
Exterior corners and intersections of interior partitions and exterior walls
Exterior corners and intersections of interior partitions and exterior walls are framed to allow space for insulation preventing uninsulated spaces in exterior walls and reduce heat loss and reduce the overall amount of wood used in the construction of the home.
Insulated door and window headers
In single story homes and in second floor walls of two-story homes, single-ply headers are used in load-bearing walls to allow for partial insulation. In non-load bearing exterior walls, headers are eliminated entirely to allow for full insulation. In two-story homes, a structural rim joist is used to eliminate the need for headers in first floor exterior walls allowing for full insulation.
Raised heel roof trusses
The heels of roof trusses where they bear on the outside walls are raised to allow for R-42 attic insulation to extend over the exterior walls reducing heat loss and improving attic ventilation.
Using engineered I-joists and beams, and OSB sheathing reduces problems associated with shrinkage and warpage, allows more flexibility in design, and reduces the impact on old growth forests.
Benefits of advanced framing
Increasing wall insulation and eliminating air spaces increases the overall R-value and integrity of the building envelope resulting in walls that are warmer in winter and cooler in summer. Approximately 40 percent of our physical comfort is due to the radiant heat exchange between our bodies and the surrounding interior surfaces. Advanced framing reduces this radiant heat exchange maintaining a more consistent level of comfort throughout a house.
Reduced framing cost
Advanced framing reduces the amount of lumber and labor needed to build your home – up to a 25 percent reduction in the amount of wood used. The cost savings are “reinvested” in additional energy-saving features such as increased insulation and high efficiency heating and cooling equipment.
Lower utility bills
By reducing the amount of heat and air that flows through the building envelope, advanced framing results in lower utility bills.
Chuck Miller GMB CGP CGB MIRM CMP MCSP CSP
President / Builder – Chuck Miller Construction Inc.