Building Code Board reviews 2024 IECC residential changes; moves IPMC fee schedule outside code

At a meeting of the Building Code Board, members approved minutes from the board’s February 6 meeting and heard staff presentations about moving the International Property Maintenance Code (IPMC) fee schedule out of the code text and a line-by-line review of changes between the 2021 and 2024 International Energy Conservation Code (IECC) for residential construction.

The change to the IPMC fee schedule is an administrative step to make fees a separate, stand-alone schedule rather than embedded in the code, staff said. “Typically when we adopt fees we adopt it in with the code for the IPMC and this is the only code we do it for,” Sean, a staff member, said. He said the move would allow future fee updates to go to the city commission without returning to this board.

Board members spent the bulk of the meeting on a detailed staff presentation of the IECC residential provisions. Melissa, a staff member, summarized dozens of reorganizations and clarifications in the 2024 residential sections and highlighted the specific requirements that she said carry practical implications for local construction.

Melissa said many sections were reorganized or converted to tables for clarity and that the overall intent of the code has not changed, but several changes could affect local practice. On air leakage, she noted the maximum air leakage rate for Climate Zone 6 was reduced to 2.5 air changes per hour (ACH) and that the code allows up to 4 ACH when a building complies with alternate provisions in the code. “The maximum air leakage rate has been reduced to 2.5 air changes per hour for Climate Zone 6 but new language has been added allowing 4 air changes per hour if the building complies with either section 1101.13.0.2 or 1101.13.3,” Melissa said. Staff told the board their current testing results have generally measured below 2 ACH.

The code now explicitly requires heat- or energy-recovery ventilators in Climate Zone 6 in some circumstances. “The requirement for heat recovery or energy recovery ventilation has been included to include Climate Zone 6,” Melissa said; the board discussed that staff had been requiring a rough-in and that the change would generally require installation of the equipment rather than only a rough-in.

Other notable technical changes described by staff include:

- New construction-document requirements for solar-ready systems (not a mandate to install solar, but documentation if solar-ready systems are used).

- Expanded and clarified definitions (for example, terms such as common areas, conditioned space, living space and occupiable space were added to coordinate with later sections).

- Differentiation between skylights and vertical fenestrations in U-factor and insulation tables; staff recommended maintaining a local amendment increasing the U-factor requirement for vertical fenestrations to 0.32.

- New provisions for insulation on slabs within 24 inches of grade and changes to basement-wall and wood-frame wall R-value guidance; staff recommended modifying a local amendment for Climate Zone 6 to set wood-frame wall insulation to R-21 or R-13 plus R-5 continuous insulation and basement walls to R-10 continuous insulation or R-15.

- New section clarifying treatment of attic knee walls when unconditioned space is on one side, treating them essentially as exterior walls.

- A rewritten duct leakage table and new testing-report requirements, including a requirement that a written report of certain test results be supplied to the building official.

- A new requirement that bathroom and toilet room exhaust fans have automated controls (timer, occupant sensor, humidity control or particulate/gaseous concentration control) and that manual-only operation be prohibited, with a specified exception where the exhaust is integrated into a whole-house mechanical system.

- A new prohibition on continuous pilots for gas fireplaces and accompanying product-listing requirements for gas fireplaces used as heaters or decorative appliances.

Melissa told board members she expected the new credit-based approach in the IECC’s compliance path (table 1108.2) to provide more flexibility for compliance by allowing builders to combine smaller efficiency measures rather than adopt a single large “package.” “Instead of saying that you have to have, say, an efficiency package for your mechanical… now they break it out into where you can get extra energy efficiency and change it so that you can get a few credits here and a few credits here,” Melissa said.

On local amendments, Melissa advised continuing some existing local provisions and deleting others where the revised model code now incorporates similar language. For example, staff recommended continuing a local amendment requiring flashing and a slip sheet over any exterior foundation insulation and recommended deleting some local amendments where the IECC language now matches the previous amendment.

Board members asked clarifying questions about the practical effects of the changes. One member expressed concern that eliminating continuous pilots could cause flue-frosting problems in very cold temperatures; Melissa said staff would research the issue and report back. “We will do some research on that,” she said.

No formal vote on adopting or changing local amendments to the code was recorded in the transcript; the meeting record shows only approval of minutes and adjournment. Sean said the IPMC fee amounts themselves were not changing as part of the proposal to relocate the fee schedule outside the code.

The board approved the February 6 minutes by voice vote. “All in favor signify by saying aye. Aye. Action is approved,” a board member said. The meeting was later adjourned by unanimous voice vote.

Staff recommended additional follow-up and indicated they would present specifics to the city commission or return with research on discrete issues (for example, fireplace pilot implications). The board did not take a formal vote on code adoption or on changing the local amendment language at this meeting.

Looking ahead, staff said they would provide the board and the commission with any required documentation if the board and elected officials pursue changes to the local amendment package or to the IPMC fee schedule.