Utah’s New Housing Law Slashes Costs for Multi-Family Builders – You Won’t Believe How!

The Housing Construction Amendments bill (HB175), passed in Utah’s 2025 General Session (effective May 7, 2025), introduces significant updates to the state’s adoption of the International Residential Code (IRC). Sponsored by Rep. Raymond P. Ward and Sen. Calvin R. Musselman, this legislation modifies construction requirements to reduce costs, streamline compliance, and expand housing options for homebuilders. Below, we outline the key provisions and their benefits for homebuilders.

1. Expanded Scope for Multi-Family Dwellings

Change: The bill amends IRC Section R101.2 to include three- and four-family dwellings of up to two levels under the same regulatory framework as one- and two-family dwellings, removing the need for automatic sprinkler systems in these structures.

Benefit: Homebuilders can construct three- and four-family dwellings more cost-effectively, as they no longer require expensive sprinkler systems. This encourages the development of denser, affordable housing options in Utah’s growing communities.

2. Eased Egress Window Requirements

Change: A new IRC Section R102.7.2 exempts existing bedrooms with non-compliant egress windows from physical upgrades if the change would compromise structural integrity or violate setback/window well rules, provided the window met codes at the time of construction.

Benefit: Homebuilders renovating older homes avoid costly window retrofits, reducing project expenses and preserving the feasibility of remodeling projects.

3. Simplified Permitting for Small Structures

Change: IRC Section R105.2 exemptions are expanded to include retaining walls under 4 feet (without surcharge), decks up to 30 inches above grade (not serving exit doors), and grade-level conex boxes under 350 square feet used for storage.

Benefit: Builders can construct these features without permits, saving time and administrative costs, particularly for accessory structures and landscaping projects.

4. Reduced Inspections and Proprietary Information Requests

Change: IRC Section R108.3 prohibits building officials from requesting proprietary information, and IRC Section R109.1.5 limits mandatory inspections to insulation, weather-resistant exterior walls, flashings, and fire-resistance-rated construction.

Benefit: Fewer inspections and no demands for proprietary data streamline the building process, lower compliance costs, and protect builders’ intellectual property.

5. Support for Accessory Dwelling Units (ADUs)

Change: The bill adds a definition for ADUs (IRC Section R202) and provides exemptions, such as relaxed fire separation requirements (IRC Section R302.3) and smoke/carbon monoxide alarm rules for ADUs during alterations (IRC Sections R314.2.2, R315.2.2).

Benefit: These changes make it easier and cheaper to build ADUs within existing homes, enabling homebuilders to meet the growing demand for affordable housing options like granny flats or rental units.

6. Flexible Foundation and Structural Requirements

Change: Amendments to IRC Sections R403.1.6, R403.1.6.1, and R404.1 allow closer anchor bolt spacing (32 inches) with fewer bolts and permit alternative foundation wall designs per IBC standards. Vertical steel in footings can be adjusted before concrete sets (IRC Section R403.1.3.5.3).

Benefit: These provisions reduce material and labor costs for foundations and allow builders to adapt designs to site-specific needs, improving efficiency without compromising safety.

7. Updated Snow Load Standards

Change: IRC Sections R301.2(3) and R301.6 replace outdated snow load tables with references to the 2018 Utah Snow Load Study, providing precise, location-specific data for Utah jurisdictions.

Benefit: Builders can design structures with accurate snow load requirements, avoiding over-engineering and reducing construction costs, especially in high-elevation areas like Heber City (60 lb/ft²).

8. Relaxed Drainage and Vapor Retarder Rules

Change: IRC Section R405.1 exempts drainage systems unless required by a geotechnical report, and IRC Section R506.2.3 lowers the vapor retarder thickness from 10-mil to 6-mil, removing ASTM E1745 Class A requirements.

Benefit: These changes cut costs for drainage and under-slab materials, allowing builders to tailor solutions based on site conditions rather than blanket mandates.

Conclusion

Utah’s Housing Construction Amendments empower homebuilders by reducing regulatory burdens, lowering construction costs, and promoting housing diversity. By easing requirements for multi-family dwellings, ADUs, egress windows, permitting, inspections, and structural designs, the bill enables builders to deliver affordable, high-quality homes more efficiently. Homebuilders should review the updated IRC sections to leverage these opportunities and stay compliant when the bill takes effect on May 7, 2025.

Read HB 175