OER: Open Educational Resources

This comprehensive code comprises all building, plumbing, mechanical, fuel gas and electrical requirements for one- and two-family dwellings and townhouses up to three stories. The 2021 IRC contains many important changes such as: Braced wall lines must be placed on a physical wall or placed between multiple walls. The rated separation for two-family dwellings is 1 hour whether or not a lot line exists between units. Emergency escape and rescue openings require a clear 36-inch-wide path to a public way. An engineered design is required for storm shelters. A habitable attic is limited to one-half the area of the story below and the dwelling requires sprinklers. Updated Wind Speed maps match IBC and ASCE 7 maps. Deck design now considers snow load, tributary area for footing and post height, and guard details. Specific requirements for deck guardrails were added. Component and cladding wind pressures in Table R301.2(2) are updated for new design wind speeds and hip or gable roof profiles. Minimum footing size tables are revised to more accurately reflect current practice. Cripple wall requirements apply only to exterior cripple walls. New appendices for cob construction and 3D printed construction are added. A 30 percent reduction of airflow is permitted for balanced ventilation systems. Commercial gas cooking appliances are prohibited. The head pressure for a water test of DWV systems increased to 10 feet. Air vacuum testing is now permitted for plastic piping DWV systems. Section P2904 for dwelling sprinklers is expanded to more closely align with NFPA 13D. An emergency service disconnect is required in a readily accessible outdoor location. A surge-protective device (SPD) is now required at the service panel. The number of receptacle outlets required for peninsular and island countertops in kitchens is determined by the area of the countertop surface.

This best practices guide is the twelfth in a series of guides for builders produced by PNNL for the U.S. Department of Energy’s Building America program. This guide book is a resource to help builders design and construct homes that are among the most energy-efficient available, while addressing issues such as building durability, indoor air quality, and occupant health, safety, and comfort. With the measures described in this guide, builders in the cold and very cold climates can build homes that have whole-house energy savings of 40% over the Building America benchmark with no added overall costs for consumers. The best practices described in this document are based on the results of research and demonstration projects conducted by Building America’s research teams. Building America brings together the nation’s leading building scientists with over 300 production builders to develop, test, and apply innovative, energy-efficient construction practices. Building America builders have found they can build homes that meet these aggressive energy-efficiency goals at no net increased costs to the homeowners. Currently, Building America homes achieve energy savings of 40% greater than the Building America benchmark home (a home built to mid-1990s building practices roughly equivalent to the 1993 Model Energy Code). The recommendations in this document meet or exceed the requirements of the 2009 IECC and 2009 IRC and thos erequirements are highlighted in the text. This document will be distributed via the DOE Building America website: www.buildingamerica.gov.