Blog post

This is part 1 of a 2 part article regarding the updates to the IRC and IECC code requirements. We strongly advise contractors acquire and refer to their own copy of the IRC and IECC for full code requirements.

International Codes, as published by the International Code Council, are the most widely used codes in construction within the United States. They have also been adopted by many federal agencies, such as the National Park Service and the Department of Defense which has led to the codes being enforced in foreign countries as well.

Here is a summary of some of the new requirements for single family homes, duplexes and townhouses that are three stories, or less, in height as dictated in the International Residential Code (IRC) and the International Energy Conservation Code (IECC).

Emergency Escape and Route Openings (EERO)

All rooms that are considered sleeping rooms and all basements must have emergency escape and rescue openings with the exception of basements that are less than 200 square feet and are not used for living and basement sleeping rooms in houses that have a residential sprinkler system that complies with NFPA 13R or 13D if there are at least one EERO and one egress door, or two EEROs from the basement. Requirements for sizes, locations, etc can be found in Section R310 of the 2018 IRC. The required opening size must be met by normal operation without requiring any tools or special knowledge for the window to open.

Minimum Window Sill Heights

According to the 2018 IRC, all windows that are more than 6 feet above the grade outside the window must have a bottom opening a minimum of 24 inches above the room’s interior floor. Exceptions can be made for windows that do not open more than 4 inches or that have window guards or opening control devices in compliance with ASTM F2090-17.

Means of Egress Doors in the IRC

2018 IRC Section R311.3.1 restricts threshold height a required exit door in residences to 1 ½ inches from the top of the the threshold to the floor or landing on each side of the door. Any other exterior door has a threshold height limited to 7 ¾ inches.

Section R311.2 states the width of the clear opening of the required egress door must be at least 32 inches from the face of the door to the door stop at the jamb or the opening and the height of the opening must be a minimum of 78 inches from the door stop at the head of the opening to the top of the threshold.

Window Installation

Section R609.1 states windows and doors must be installed according to the fenestration manufacturer’s instructions and flashing must be in accordance with Section R703.4. Installation of flashing around the window is required to be installed in shingle-fashion to prevent entry of water into the wall cavity or building framing components. There are also references to some AAMA standards for flashing regarding self-adhered membranes, fluid-applied flashing and mechanically applied flashing.

Safety Glazing

As found in Section R308.4, safety glazing is required in the following locations:

  • In and near swinging and sliding doors
  • Large lites of glass near walkways
  • Around tubs, showers, pools and other similar fixtures
  • Near stairways ramps and the landings for both

Glazing must be labeled per the Consumer Product Safety Commission (CPSC) 16 CFR 1201 requirements. Exceptions may be made for openings less than 3 inches in diameter in doors or decorative glass and glazing provided with a protective bar.


The 2018 IRC requires window mullions to undergo testing or structural calculations to demonstrate the ability to meet structural requirements. If structural calculations are used, the mullion deflection is limited to L/175 of the length on the long edge of the glass being supported.

Replacement Windows

In both the 2018 IECC and IRC, replacement windows must comply with the energy conservation requirements for fenestration in new construction, regardless of what the replacement is. WOCDs must also be used on replacement windows if it would be required for that location on new construction.

Sunroom Additions

The 2018 IECC permits thermally isolated sunrooms to have glazing with a maximum U-factor of 0.45 in climate zones 2 to 8. The thermally isolated sunroom must be separated from the remainder of the building by exsiting exterior wall construction, or construction that adheres to the 2018 IECC requirements for exterior walls. The sunroom must also be equipped with their own heating or cooling systm, or the ability to be controlled as a separate zone on the thermostat.

Site-Built Windows

All site-build windows must be tested for design pressure in accordance with ASTM E330. There is also reference to ASTM E1300-12AE1 for design addressing several types of layups and support combinations. An exemption may be made for exterior windows and doors that are tested and labeled in accordance with NAFS-17.

Skylights and Sloped Glazing

Factory-built unit skylights must adhere to the following requirements:
Skylights intended to be installed in a single roof opening without intermediate framing must be tested and labeled in accordance with NAFS-17.
Skylights subject to snow load, wind and dead load are permitted to be evaluated for different positive and negative design pressures.
Tubular Daylighting Devices (TDDs) are also subject to the criteria for factory-built skylights.

Section R308.6.3 includes requirements for screening under skylights and sloped glazing, and are consistent with previous editions, including the requirement that screening be securely fastened and able to support twice the dead weight of the glass.

Note: The above information is a summary of the major requirements recently published in the 2018 I-codes, this is not a full listing of all updated requirements. We advise our customers to always refer to their own copy of the the IRC and IECC for the code(s) relevant to their project.

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