Significant changes to the 2018 International Residential Code

The 2018 Significant Changes guides are available for the International Building, Residential, Fire, Plumbing, Mechanical and Fuel Gas Codes. This valuable series can help any code user save time by zeroing in on the most critical changes in the 2018 International Codes (I-Codes). The Code Council’s technical experts provide summaries, analysis and graphics for these changes making them clear and easy to understand.

2018 International Residential Code

A clarification to Section N1101.6 (Definition of Air Barrier) states that the definition for air barrier has been revised for clarification and the duplicate definition for continuous air barrier has been removed.

An air barrier is an important component of the building thermal envelope to reduce air infiltration into the dwelling unit as well as exfiltration of air from the conditioned portions of the building. Table N1102.4.1.1 details the mandatory requirements for installation of the required air barrier and insulation. To be effective, the air barrier must be continuous and breaks or joints in the air barrier must be sealed. Combinations of many different materials satisfy the air barrier requirements, including plywood, oriented strand board (OSB), gypsum board and extruded polystyrene (impermeable insulation) sheathing, to name a few. Air-permeable insulation is not approved as an air barrier.

Sealing of joints and breaks is accomplished with tape, caulking or sealants designed for the specific application. Revisions to the definition of air barrier are editorial to clarify the meaning and to better align with the code provision requiring continuity. The definition for continuous air barrier has been removed because it is redundant; air barriers must always be continuous. The air leakage rate of the building thermal envelope is measured through the mandatory blower door test.

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