9 Steps to A Greener Code
New homes built using the 2009 International Residential Code (IRC) or International Energy Conservation Code (IECC) 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 (ICF), 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: