Sub-sections in this division:
Attic Access — Size and Clearance
Required where vertical height ≥ 30 in over at least 30 sq ft. Rough opening minimum 22 in × 30 in. Ceiling access requires 30-in clear headroom above on at least one side. Where mechanical equipment is in attic, access must also comply with UMC Section 304.4.
IRC R807.1 (locally amended)
Climatic Design Criteria — Wind & Seismic
Wind speed 98 mph for elevations below 3,900 ft; Seismic Design Category D; frost line 1 ft below 5,000 ft; termite risk Moderate to Heavy. Wind exposure category C unless site-specific justification provided. Above 3,900 ft: defer to IBC.
IRC Table R301.2 (locally amended)
Energy Efficiency — Insulation Minimums (Climate Zone 3)
Ceiling: R-38. Wood-framed wall: R-20 or R-13+5ci or 0+15ci. Floor: R-19 or R-13+5ci or 15ci. Unheated slab edge: none required. Vertical fenestration: max U-factor 0.30, max SHGC 0.25. Skylight: max U-factor 0.53, max SHGC 0.28.
IECC 2024 Tables R402.1.2 and R402.1.3 (Climate Zone 3)
Live Load Requirements
Sleeping and habitable areas: 40 psf. Garages: 50 psf uniform / 2,000 lb concentrated. Uninhabitable attics without storage: 10 psf; with limited storage: 20 psf.
IRC Table R301.5 (locally amended)
Masonry Fences and Retaining Walls — Permit Required
Separate building permit required per parcel for fences, walls, and retaining walls. Retaining walls retaining more than 24 inches require engineering by a registered design professional. Footings must be designed by a registered Civil or Structural Engineer for all imposed loads including soil pressure, surcharge, seismic, and hydrostatic forces per IBC Chapter 18. Default design parameters where no soils report: assume 60 psf/ft lateral soil pressure, Exposure Class S2 (severe sulfate exposure) — concrete minimum f'c 4,000 psi for footings in sulfate soils. No fence or wall may block a natural flow path. Prohibited materials: pointed pickets, electrocution components, embedded glass, barbed/razor wire.
IBC 2024 Appendix Q / Henderson Development Code Section 19.10.6
Retaining Wall — Footing and Structural Design Requirements
Retaining walls over 24 inches (top of footing to top of wall) require a building permit and engineering by a registered Civil or Structural Engineer. Footing design must account for: lateral soil pressure (minimum 60 psf/ft unless geotechnical report specifies otherwise), surcharge loads, seismic forces (Seismic Design Category D), and hydrostatic pressure where applicable. Concrete minimum compressive strength f'c = 3,000 psi general; f'c = 4,000 psi where soils report indicates Exposure Class S2 (severe sulfate) conditions, which is common in Southern Nevada soils. Footings must extend below frost depth (minimum 12 inches below finish grade in the Las Vegas Valley). Required inspections: footing excavation, reinforcing steel placement, drainage/dampproofing before backfill.
IBC 2024 Appendix Q / IBC Chapter 18 / Henderson Municipal Code Section 15.08
Townhouse — Structural Independence
Each townhouse unit must be structurally independent except: shared foundations, structural sheathing fastened to common wall framing, nonstructural coverings, flashing at common wall roof termination, and units separated by common wall per R302.2.2.
IRC R302.2.6 (locally amended)
Climatic & Geographic Design Criteria
Las Vegas design values (below 1,600 ft elevation): Ground snow load 5 psf; Design wind speed 98 mph; Seismic Design Category D; Frost line depth 1 ft; Termite: Moderate to Heavy. These SNBO-published values replace the generic IRC table and govern all structural design.
SNBO 2024 IRC Amendment, Table R301.2
Floor Live Loads
Sleeping room floor live load is set at 40 psf per SNBO local amendment (footnote: actual live load governs when known to exceed table values). All other residential floor live loads per 2024 IRC Table R301.5.
SNBO 2024 IRC Amendment, Table R301.5
Foundation Waterproofing & Dampproofing
Section R406.2 (foundation waterproofing and dampproofing) is specifically amended for Southern Nevada conditions. When basements are installed, plans must show a cross-section with materials, exterior waterproofing, and egress window well details.
SNBO 2024 IRC Amendment §R406.2; IRC R406
Framing Plans & Lateral Force Resisting System
Framing plans must show trusses, joists, beams, headers, bearing walls, and all framing hardware. Lateral force resisting system must document shear walls, drag struts, collectors, diaphragm, nailing schedule, and hold-downs. A complete load path must be demonstrated from point of load to all resisting elements.
CLV Residential Submittal Requirements §1.3.C; 2024 IRC Chapter 6
Truss Submittals
Truss design and shop drawings must be prepared, stamped, and signed by a Nevada-licensed engineer and submitted prior to permit issuance (or via deferred submittal). The truss fabricator must appear on the Clark County approved fabricators list. The Engineer of Record must confirm truss calculations comply with design intent.
CLV Residential Submittal Requirements §1.3.C; IRC R802