9 Steps to A Greener Code

New homes built using the 2009 International Residential Code (IRCInternational Residential Code. The one- and two-family dwelling model building code copyrighted by the International Code Council. The IRC is meant to be a stand-alone code compatible with the three national building codes—the Building Officials and Code Administrators (BOCA) National code, the Southern Building Code Congress International (SBCCI) code and the International Conference of Building Officials (ICBO) code.) or International Energy Conservation Code (IECC International Energy Conservation Code.) will be more energy efficient than ever. As a consequence, a builder’s world may become a bit more complex and, in some cases, a bit more expensive. Recent spikes in energy costs have increased the attention on regulatory measures that limit energy waste.

STEP 5: INSULATING MASS WALLS (Section N1102.2.4)

The code: Refined insulation standards have been applied to mass walls to increase their performance in both hot and cold climates.

What it means to you: Code allows mass walls to be built to two different thermal-resistant standards based on the configuration of insulation in the assembly. The IRC classifies a mass wall as an above-grade wall made of concrete block, concrete, insulated concrete forms (ICFInsulated concrete form. Hollow insulated forms, usually made from expanded polystyrene (EPS), used for building walls (foundation and above-ground); after stacking and stabilizing the forms, the aligned cores are filled with concrete, which provides the wall structure.), masonry cavity, brick, earth, adobe, compressed-earth block, rammed earth, and solid timber/logs. Insulation installed on a mass wall creates what’s called “thermal lag.” The insulation increases the time it takes for hot or cold temperatures to transfer from the mass into the living space, reducing the strain on mechanical systems. Insulating the interior of a mass wall is more expensive because code requires a greater thermal resistance, which means more insulation.

The 2009 building codes reflect practices that not only increase energy efficiency—air-sealing measures and increased insulation, for example—but also address sustainable building practices, such as moisture control.

Other segments of this series:

Part 1: Air Sealing
Part 2: Insulation
Part 3: Lighting
Part 4: Programmable Thermostats
Part 5: Insulating Mass Walls
Part 6: Efficient Windows
Part 7: Insulating Mechanical Pipes
Part 8: Exceeding the Energy Code
Part 9: Vapor Retarders