Building Planning

Application

Buildings and structures, and parts thereof, shall be constructed to safely support all loads. This section establishes the minimum design criteria for residential structures.

Climatic and Geographic Design Criteria

Establishes the design criteria table that every jurisdiction must fill out — ground snow load, wind speed, seismic zone, weathering probability, frost line depth, termite infestation probability, ice barrier underlayment, flood hazards, air freezing index, and mean annual temperature. This is the foundational reference for all structural and material requirements.

Wind Design Criteria

Sets wind speed requirements based on risk category and geographic location. Ultimate design wind speeds from ASCE 7-16 Figure 26.5-1A. Determines fastener schedules, roof sheathing attachment, and opening protection requirements. Critical for any exterior restoration scope.

Protection of Openings

In wind-borne debris regions, glazed openings must be protected with impact-resistant glazing or shutters tested to ASTM E1996 and E1886. Applies when within 1 mile of the coast where basic wind speed >= 130 mph, or anywhere wind speed >= 140 mph.

Glazing - Mississippi Wind-Borne Debris Region Requirements (Gulf Coast)

Mississippi Gulf Coast Wind-Borne Debris Region (WBDR) requires impact-resistant glazing OR approved shutters for all glazed openings. Applies where wind speed ≥140 mph or within 1 mile of coast ≥130 mph. ASTM E1886/E1996 testing. Miami-Dade NOA accepted. Garage doors need wind AND impact rating. Post-Katrina requirement. Verify WBDR status with local building official.

Alternative Seismic Bracing - Shelby County Prescriptive Path

SHELBY COUNTY SEISMIC PRESCRIPTIVE PATH - For SDC D1 (Memphis area): 1/2" anchors at 48" o.c., 3x3 washers, hold-downs (4,200 lb min), sole plate 16d at 4" o.c., continuous load path, veneer ties at 18" vertical. Alternative to full engineering.

Seismic Design - Hawaii SDC D Requirements

Hawaii is Seismic Design Category D due to volcanic and tectonic activity. Requirements include anchor bolts at 6 ft o.c. max (within 12" of corners), hold-downs at braced wall ends, cripple wall bracing, masonry veneer seismic anchorage, and water heater strapping. Big Island most seismically active.

Seismic Design Requirements - New Madrid Zone (West Tennessee)

NEW MADRID SEISMIC ZONE (West TN) - SDC D0-D2 counties require: 1/2" anchor bolts at 48" o.c. with 3x3 washers, hold-downs at braced panels, chimney reinforcement, water heater strapping. SDC D2 (Tipton, Lake) is highest risk in TN. Liquefaction risk near Reelfoot Lake. MANDATORY engineered foundation or prescriptive IRC R403 compliance.

Snow Loads

The ground snow load shall be determined from Figure R301.2(5) or per the authority having jurisdiction. CRITICAL FOR MONTANA: Ground snow loads in Montana range from 30 psf on the eastern plains to well over 150 psf in mountain areas. Many Montana locations require site-specific snow load analysis per ASCE 7. Roof framing, connections, and structural design must account for these extreme loads. Drifting snow provisions also apply per IRC R301.2.3.

Exposure Category

Defines wind exposure categories B, C, and D based on surrounding terrain. Exposure B: urban/suburban. Exposure C: open terrain. Exposure D: flat, unobstructed coastal areas. Affects component and cladding wind pressure calculations for roofing, siding, and windows.

Snow Load and Frost Design - Vermont (ASCE 7-16 + IRC Chapter 3)

Vermont has among the highest ground snow loads in the continental US. Snow loads are site-specific and elevation-dependent, ranging from 50 psf in the Champlain Valley to 150+ psf at mountain elevations. Frost depth 48-60 inches drives foundation requirements.

Exterior Walls

Specifies fire-resistance ratings and fire separation distances for exterior walls, projections, openings, and penetrations based on proximity to property lines.

Townhouse Separation - Unsprinklered (Tennessee)

TOWNHOUSE FIRE WALLS - Because TN prohibits residential sprinklers, ALL townhouse common walls must be 2-HOUR fire-resistance rated (not 1-hour). No sprinkler trade-off available. Parapets required unless both sides Class A roof. This is MORE RESTRICTIVE than states allowing sprinklers.

Glazing

Parent section for safety glazing requirements.

Human Impact Loads

SAFETY GLAZING REQUIRED in hazardous locations per CPSC 16 CFR 1201.

Hazardous Locations — Safety Glazing

Requires safety glazing (tempered or laminated) in hazardous locations: within 24 inches of doors, in bathroom enclosures, within 60 inches of walking surface near tubs/showers, and in glass areas larger than 9 sq ft adjacent to walking surfaces. Critical for window and door replacement scopes.

Skylights and Sloped Glazing

SKYLIGHT REQUIREMENTS: Must be listed/labeled per AAMA/WDMA/CSA 101. Safety glazing required (tempered, laminated, or approved plastic). ENERGY: Zone 4A max U-factor 0.55, SHGC 0.40. Proper curb construction and flashing critical - use manufacturer flashing kits. Fall protection may be required for low-slope skylights.

Glazing - Arizona Requirements

AZ glazing requirements emphasize low SHGC in desert zones (0.25) and fire-resistant glazing in WUI zones. Energy performance varies significantly by climate zone.

Glazing and Windows - Hawaii Impact Protection and SHGC Requirements

Hawaii window requirements include impact protection (impact-resistant glazing OR shutters) in wind-borne debris regions (most of Hawaii). SHGC ≤0.25 is CRITICAL in Climate Zone 1 to control solar heat gain (more important than U-factor). Safety glazing required in hazardous locations. Product approval for wind resistance required. Egress windows required in sleeping rooms.

Windows and Glazing - Indiana Energy and Safety Requirements

Indiana window energy requirements vary by climate zone. Zone 5A (northern/central): U-factor ≤0.30 (stricter). Zone 4A (southern): U-factor ≤0.35. SHGC ≤0.40 both zones. Safety glazing required in hazardous locations. Egress windows required in sleeping rooms and basements (common in IN). No impact resistance required (not in wind-borne debris region).

Windows and Glazing - Vermont (IRC 2015/2018 + RBES 2020)

Window requirements in Vermont combine IRC safety glazing with RBES 2020 stringent energy performance for Zone 6A. U-factor 0.30 max is one of the most demanding in the nation. Triple-pane or high-performance Low-E required.

Emergency Escape and Rescue Openings

Basements and every sleeping room shall have at least one operable emergency escape and rescue opening. Minimum opening: 5.7 sq ft (5.0 sq ft at grade floor), minimum width 20 inches, minimum height 24 inches. Maximum sill height 44 inches above floor. COLORADO NOTE: Window wells required where egress windows are below grade. Wells must have ladder/steps if over 44 inches deep.

Emergency Escape and Rescue Openings

Basements and sleeping rooms require at least one operable emergency escape opening: minimum 5.7 sq ft net clear opening (5.0 sq ft at grade floor), minimum 24 inches high, minimum 20 inches wide, maximum 44 inches sill height. Window replacements in bedrooms must maintain egress compliance.

Egress Door

EGRESS DOOR - Min one per dwelling unit. 32" clear width, 78" min height. Side-hinged.

Landings at Doors

DOOR LANDINGS - Required each side of exterior doors. 36" min in direction of travel.

Stair Riser Heights (West Virginia Amendment)

Section R311.7.5.1 — Stair Riser Heights (West Virginia Amendment). West Virginia Amendment per 87 CSR 4 §4.1.i.1: The maximum riser height shall be EIGHT AND ONE-QUARTER (8-1/4) INCHES. NOTE: Standard IRC 2018 allows 7-3/4" maximum. West Virginia ...

Stair Tread Depth (West Virginia Amendment)

Section R311.7.5.2 — Stair Tread Depth (West Virginia Amendment). West Virginia Amendment per 87 CSR 4 §4.1.i.2: The minimum tread depth shall be NINE (9) INCHES....

Doors and Egress - Vermont (IRC 2015/2018 + RBES 2020)

Door requirements in Vermont combine IRC egress with RBES 2020 energy performance for Zone 6A. Exterior door U-factor 0.30 max. Storm doors common for additional thermal performance. Entry door landing and snow clearance considerations.

Guards — Where Required

Guards are required on open sides of walking surfaces (porches, decks, balconies, stairs) more than 30 inches above grade. Minimum guard height 36 inches (42 inches in ICC 2021+). Balusters spaced so a 4-inch sphere cannot pass through. Relevant for deck and exterior trim scopes.

Townhouse Automatic Fire Sprinkler Systems

Requires NFPA 13D automatic fire sprinkler systems in townhouses. Alternative: provide 2-hour fire-resistance-rated wall assemblies or 1-hour rated walls with sprinklers on each side.

Automatic Fire Systems (OK Amendment)

Residential fire sprinklers NOT required in Oklahoma. IRC R313.2 moved to non-mandatory Appendix U.

Residential Fire Sprinkler Prohibition

SPRINKLER PROHIBITION - Tennessee law PROHIBITS requiring residential fire sprinklers. T.C.A. § 68-120-101(a)(8) deletes IRC R313.1 and R313.2 statewide. Does NOT apply to: commercial buildings (IBC), assisted living facilities, or structures voluntarily choosing sprinklers. Insurance may still incentivize voluntary installation.

Termite Protection - Hawaii Severe Zone Requirements

Hawaii is a SEVERE termite zone with Formosan subterranean termites (most destructive in US), drywood termites, and ground termites. Soil treatment OR physical barriers OR pressure-treated lumber REQUIRED. Wood-to-ground clearance: 6" minimum. Termite shields recommended. Annual inspection strongly recommended. Tent fumigation common for drywood termites.

Termite Protection - Mississippi Very Heavy Zone (Formosan on Coast)

Mississippi is VERY HEAVY termite zone statewide. Formosan subterranean termites on Gulf Coast (most destructive in US). Soil treatment OR physical barriers OR pressure-treated lumber REQUIRED where codes adopted. Wood-to-ground clearance: 6" minimum. Annual inspection strongly recommended. Termite bonds common. Warm humid climate year-round.

Flood-Resistant Construction — General

Buildings in flood hazard areas (FEMA zones A, AE, AH, AO, V, VE) must comply with ASCE 24. Lowest floor must be at or above the base flood elevation (BFE). Flood-resistant materials required below BFE. Elevation certificate typically required.

Flood-Resistant Construction - Hawaii Coastal Requirements

Hawaii flood zone requirements: V-Zones (coastal high hazard) require construction on piles/columns with bottom of lowest structural member at/above BFE, breakaway walls below BFE, and no fill for structural support. A-Zones require lowest floor at/above BFE with flood openings in foundation walls. Tsunami evacuation zones apply to all coastlines. Corrosion-resistant materials required. Elevation Certificate needed.

Flood-Resistant Construction - Indiana River Corridors

Indiana flood zone requirements: A-Zones require lowest floor at/above BFE, flood-resistant materials below BFE, flood openings in foundation walls (1 sq in per sq ft of enclosed area). Major flood zones along Ohio River, Wabash River, White River. Indiana DNR floodway permit may be required. NFIP compliance required for mortgages. Elevation Certificate needed.

Flood-Resistant Construction - Mississippi Coastal and Riverine Requirements

Mississippi flood requirements: V/VE zones (coastal) require piles/columns with bottom of structure at/above BFE, breakaway walls below BFE. A/AE zones require lowest floor at/above BFE with flood openings (1 sq in per sq ft). Gulf Coast has extensive V-zones. Post-Katrina: higher BFEs, freeboard requirements. Elevation Certificate required. NFIP mandatory for mortgages in SFHA.

Wildfire Hazard Mitigation (Local Adoption)

Where adopted by local jurisdiction, construction in designated wildfire hazard zones must comply with fire-resistant requirements. Class A roof assemblies required. Fire-resistant exterior wall coverings. Ember-resistant vents. Tempered glass windows. Defensible space. COLORADO NOTE: Many mountain and foothill communities have adopted WUI codes. Post-Marshall Fire (2021), Boulder County has strictest requirements. Colorado State Forest Service provides defensible space guidance.