Comparison of U.S. and Canadian Building Codes

For those Canadian firms that are contemplating the export of housing or housing components, the United States is a compelling market - close, familiar and large. In fact, more than 90% of Canadian housing exports are destined for the U.S. American house designs, technology and regulatory requirements are very similar to Canada's. However, there are differences that exporters need to be aware of. Canada Mortgage and Housing Corporation recently undertook a comparative study of U.S. and Canadian building codes in order to provide advice to exporters on key regulatory issues. This bulletin highlights the findings.

Current U.S. Building Code Environment:

The American regulatory environment has traditionally been more fragmented than Canada's. There are five major model building codes in active use across the U.S. at this time. In addition, there are a number of codes developed by individual states or cities. Also, each state and municipality may apply additional regulations and approval requirements to the adopted model code. So an exporter that wishes to market in several areas will have to meet the requirements of more than one code.

Prior to the development of the International Codes, there were three competing model codes:

• the National Building Code (NBC) by the Building Officials Code Administrators (BOCA) in the northeast;
• the Standard Building Code (SBC) by the Southern Building Code Congress International (SBCCI) in the south; and
• the Uniform Building Code (UBC) by the International Conference of Building Officials (ICBO) in the west.

To address the difficulties being faced by designers, builders and manufacturers who required approvals in more than one state, the International Code Council was created in 1994 and the first set of unified model codes, called International Codes (or I-codes), was published in 1998, followed by revisions in 2000 and 2003.

These new codes are being adopted increasingly across the U.S. and are supported by the National Association of Home Builders. The three major code producing bodies that produced the NBC, the SBC and the UBC formally merged together in 2003 and will no longer be updating the previous codes.

However, there remain many exceptions to the use of the International Codes. Individual states and municipalities may still use the previous model codes, or may produce their own code, or may apply additional requirements to the adopted model code.

These states include:

• based on the UBC: California, Colorado, Kansas, Minnesota, Montana, Nebraska, Nevada, New Mexico, Washington, Wyoming;
• based on the SBC: Arkansas, Florida, Louisiana, Mississippi, and Tennessee;
• based on the NBC: Connecticut, Maine, New Jersey, Vermont, Virginia, West Virginia and Washington D.C.

In addition, the National Fire Protection Association has developed its own Building Construction and Safety Code.

Key Differences Between the International Residential Code and Canadian Codes:

For housing exporters, the International Residential Code (IRC) is the most significant model code since it applies to one and two family dwellings, including detached homes, townhouses and duplexes. The IRC is currently adopted statewide in 19 states and is accepted by some individual municipalities in a further 16 states.

While there are many similarities between U.S. and Canadian codes, there are also some significant differences. Many Canadians may have the perception that Canadian codes are superior or that compliance with Canadian requirements should result in approval in the U.S., but in fact the performance levels specified in the IRC often exceed Canadian requirements. The following summarizes the key differences found in the IRC.

Scope: The IRC is more comprehensive and inclusive than Canadian codes. It includes requirements for plumbing, electrical and fuel gas. Many additional and innovative construction methods are contained as sections of the code, such as insulated concrete forms (ICFs), light steel framing, exterior insulation and finish systems (EIFS) and structural insulated panels (SIPs). Requirements for special conditions, such as flooding, earthquakes and high winds, are extensive. The IRC is also illustrated. These additions result in a document that is more than three times the size of Part 9 of the National Building Code of Canada.

Dimensions: Minimum dimensions for exits, stairs, etc. are slightly larger. All dimensions are expressed in imperial units.

Fire Safety: Some fire resistance ratings are longer. Requirements for escape windows and smoke alarms are more stringent.

Acoustic Separations: Sound transmission class (STC) ratings only need to be 45 between units instead of 50, although floors also need to have an impact insulation class rating, which is not required in Canada.

Termites: Measures to protect against termites, which are common throughout much of the U.S., are more detailed.

Framing: Joist, lintel (header) and rafter spans are more conservative in some cases. Requirements for jack studs at openings in walls are more stringent.

Wind and Seismic Design: There are many additional provisions for wind and seismic design resulting in more stringent structural requirements for wall bracing, foundation and roof anchorage and for windows. These requirements exceed those in Canada even where the wind and seismic loads are not great. Coastal and hurricane prone areas have particularly demanding requirements.

Vapour Barriers: These are not required on the warm side of assemblies in the southern states.

Duct Sealing: All joints in ducts are required to be sealed, even if the ducts are run entirely within conditioned space.

Air Tightness and Ventilation: There remain two key areas where Canadian requirements are more stringent. The IRC calls for uncontrolled air leakage to be controlled, but does not require a continuous air barrier. Also, the IRC does not require continuous mechanical ventilation, although the Americans are moving rapidly to upgrade this area and a number of individual states have mechanical ventilation requirements similar to those in Canada.

Energy Efficiency Requirements:

The IRC has extensive provisions and options for energy efficiency that are based on those of the International Energy Conservation Code (IECC). At present, 38 states have adopted the energy efficiency requirements of the IRC, IECC or earlier Model Energy Code.

Requirements are based on 19 different climate zones. The prescriptive insulation requirements are significantly higher than those in Canada for houses in similar climate zones. Compliance can also be achieved through trade-offs among building envelope components and through detailed analysis of the entire house.

In the southern U.S., the IRC/IECC requirements reflect a need to reduce air conditioning loads by requiring a solar heat gain coefficient (SHGC) of less than 0.4.

Due to higher energy costs and the availability of various incentives, tax rebates and energy efficient mortgages, energy labelling has become very important in the U.S. market. The Americans have developed a home energy rating system (HERS) for houses that is based upon the performance analysis methods outlined in the IECC. The Energy Star Program for new houses is based upon the HERS rating and inspection procedures. Energy Star homes are required to exceed the performance of a house meeting the applicable energy code by 30% or more. The required inspections include testing of the air leakage from ducts, and testing the air leakage of the house. Energy Star labelling is also available for several products, such as windows and heating systems.

Requirements for Factory-Built Housing:

The U.S. Department of Housing and Urban Development (HUD) produces a special code, HUD 3280, for manufactured houses. This applies nationally and is pre-emptive of other state codes. The requirements are largely performance-based rather than prescriptive. HUD also stipulates requirements for design approval and for inspection of the production facilities by qualified agencies. A manufacturer's "Data Plate" and an inspection "Certificate Label" are required to be attached to each manufactured house for conformance with HUD.

Modular and panelized housing are generally governed by building codes. For closed systems that can't be inspected easily on site, manufacturers will also require inspection and certification of the Canadian production facilities for export to the U.S.

Requirements for Products:

As in Canada, local building officials rely on third party testing and certification for product acceptance. Conventional products are tested and certified to standards by accredited labs, while innovative and proprietary products require an assessment by an evaluation service.

The acceptance and certification of Canadian building products in the U.S. may require the application of different test standards by American labs and evaluation services. Canadian tests standards may be acceptable in some cases. Some Canadian testing agencies are accredited in the U.S.

The evaluation services of the former National Evaluation Service (NES), and those of ICBO, BOCA and the SBCCI were merged into the International Code Council Evaluation Service (ICC-ES) in 2003. This may help to streamline the evaluation and approval of new products in the U.S.

Assessment

Exporters will find U.S. codes and standards to be more similar to Canada's than any other export market. However, there are many key differences that exporters need to be aware of. U.S. requirements are more stringent and comprehensive in some cases.

The new International Codes are becoming increasingly adopted, but the current regulatory environment remains quite fragmented with many local differences. It is therefore essential for exporters to discuss specific requirements with local building officials.

The acceptance of Canadian product testing and certification will depend on the jurisdiction involved, so exporters should check with local officials and also with the new ICC Evaluation Service.

Energy labelling is very popular in the U.S. and exporters should consider applying for Energy Star ratings.

Guide for Exporters:

Guide for Exporters to U.S. Residential Building Codes
The purpose of the Guide is to help Canadian manufacturers gain an understanding of U.S. building codes and regulations for housing and how they differ from those in Canada. The main focus is on the International Residential Code that is emerging as the prevailing standard for residential construction in the U.S.

The Guide includes the following:

• an overview of the different U.S Building Codes, the development of the International Codes and the current code status in all U.S. states;
• an extensive list of the key differences between the International Residential Code and the National Building Code of Canada;
• a review of U.S. Energy Codes, added requirements for energy efficiency and ventilation in some states and the Energy Star Program;
• requirements for factory-built housing;
• standards and approvals that are required for selected housing products in the U.S.

For Further Information:

Terry Robinson
Senior Consultant, Research and Market Access
CMHC International, National Office
700 Montreal Road
Ottawa, Ontario K1A 0P7
Tel.: (613) 748-4893, Fax: (613) 748-2302
E-mail: trobinso@cmhc.ca

Paulina Barnes
Trade Consultant
CMHC International, Ontario Business Centre
100 Sheppard Avenue East, Suite 300
Toronto, Ontario M2N 6Z1
Tel.: (416) 218-3331, Fax: (416) 250-3203
E-mail: pbarnes@cmhc.ca

Commercial officers in Canadian consulates in the U.S.:
http://www.infoexport.gc.ca

General advice on exporting to the U.S.:
http://www.dfait-maeci.gc.ca/can-am/menu-en.asp

CMHC's new Guide provides a list of useful websites on U.S. codes and standards. The following are a few of the key sites:

International Code Council:
http://www.iccsafe.org

International Code Council Evaluation Service:
http://www.icc-es.org

U.S. Department of Energy:
http://www.energycodes.gov
http://www.eren.doe.gov/buildings/energy_tools

Energy Star:
products: http://www.energystar.gov/productshouses: http://www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_index

U.S. Department of Housing and Urban Development (HUD) Code:
http://www.hud.gov/offices/hsg/sfh/mhs/mhshome.cfm

American National Standards Institute:
http://www.ansi.org