Low to Moderate for experienced DIYers with a strong understanding of building codes, structural engineering, and electrical work. Professional contractors are highly recommended for optimal code compliance and structural integrity.
The construction of a sunroom or four-season room involves significant structural integration with the existing dwelling, requiring proper foundation work (to DuPage County's 42" frost depth), adherence to strict energy efficiency standards for Climate Zone 5, and specialized electrical installations. It often necessitates multiple inspections and coordination between various trades, elevating its complexity beyond minor renovations.
Project Guidelines & Rules
General Permitting & Planning
3 Rules
Permit Application
Contact your local building department for specific application forms, required drawings (site plan, foundation plan, floor plan, elevations, structural details, energy calculations), and fee schedules.
Zoning Compliance
Ensure proposed construction complies with local zoning ordinances regarding setbacks, impervious surface coverage, and accessory structure definitions.
Construction Documents
Detailed plans prepared by an Illinois-licensed architect or structural engineer may be required, particularly for complex designs or where structural modifications to the existing dwelling are involved. (2024 IRC R106.1)
Foundations & Structural Requirements
6 Rules
Frost Depth Protection
All exterior footings and foundation walls shall extend at least 42 inches below finished grade or be otherwise protected from frost heave. (2024 IRC R403.1.1)
Foundation Drainage
A drainage system shall be installed at or below the area to be protected from freezing, and a minimum of 6 inches of granular fill is required under concrete slabs on grade. (2024 IRC R405.1)
Connection to Existing Structure
The sunroom structure must be adequately anchored and structurally connected to the existing dwelling to resist uplift and lateral forces, designed for local wind and snow loads. (2024 IRC R301.2, R502.2.2)
Live & Snow Loads (Roofs)
Roofs must be designed to safely support a minimum live load of 20 PSF, and a ground snow load of 30 PSF for DuPage County, as well as dead loads. (2024 IRC R301.6, Table R301.2(1))
Live Loads (Floors)
Floors shall be designed for a minimum uniform live load of 40 PSF. (2024 IRC R301.6, Table R301.2(1))
Bracing and Shear Walls
Walls perpendicular to exterior walls and adequately anchored to the foundation and roof structure shall provide shear resistance to resist wind forces. (2024 IRC R602.10)
Building Envelope & Energy Efficiency (DuPage County Climate Zone 5)
6 Rules
Wall Insulation (Above Grade)
Walls shall meet or exceed R-15 continuous insulation, or R-20 cavity insulation, or R-13 cavity insulation plus R-5 continuous insulation. (2024 IRC Table N1102.1.2 for Climate Zone 5)
Roof/Ceiling Insulation
Roofs and ceilings shall meet or exceed R-49 insulation. (2024 IRC Table N1102.1.2 for Climate Zone 5)
Floor Insulation (Over Unconditioned Space)
Floors over unconditioned spaces (e.g., crawl space, garage) shall meet or exceed R-30 insulation. (2024 IRC Table N1102.1.2 for Climate Zone 5)
Slab Edge Insulation (if slab on grade)
Slab-on-grade floors must have R-10 insulation for 24 inches vertically or horizontally at the slab edge. (2024 IRC Table N1102.1.2 for Climate Zone 5)
Air Sealing
The building thermal envelope shall be sealed to limit air leakage, including caulking and sealing at major connections. (2024 IRC N1102.4.1)
Vapor Retarder
Class I or II vapor retarders required on the interior side of frame walls in Climate Zone 5. (2024 IRC R702.7)
Fenestration (Windows, Skylights & Doors)
3 Rules
Fenestration U-Factor & SHGC
Windows shall have a maximum U-factor of 0.30 and a maximum SHGC of 0.40. Skylights shall have a maximum U-factor of 0.55. (2024 IRC Table N1102.1.2 for Climate Zone 5)
Safety Glazing
Glazing in hazardous locations (e.g., doors, adjacent to doors, large panels near walking surfaces, bathtub/shower enclosures) shall be safety glazing. (2024 IRC R308.4)
Emergency Escape & Rescue Openings
If the sunroom is used for sleeping or adds a bedroom, an emergency escape and rescue opening is required. (2024 IRC R310.1)
Electrical Requirements
7 Rules
General Wiring & Protection
All electrical wiring and installations must comply with the 2023 National Electrical Code. (2023 NEC 90.2)
Branch Circuits
At least one 15-ampere or 20-ampere general-purpose receptacle branch circuit must be provided. Lighting circuits must be separate. (2023 NEC 210.11, 210.70)
Receptacle Outlets
Receptacle outlets shall be installed so that no point along the wall line is more than 6 feet horizontally from a receptacle outlet. GFCI protection required for all 125-volt, single-phase, 15- and 20-ampere receptacles in sunrooms. (2023 NEC 210.52(A), 210.8(A)(3))
Lighting
At least one wall-switch-controlled lighting outlet shall be installed in every habitable room and bathroom. (2023 NEC 210.70(A)(1))
Arc-Fault Circuit Interrupter (AFCI)
All 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets or devices installed in sunrooms and similar rooms shall be AFCI protected. (2023 NEC 210.12(A))
HVAC Equipment Circuits
Dedicated branch circuits are required for permanently installed heating, ventilation, and air conditioning equipment, sized according to the manufacturer's instructions. (2023 NEC 210.23, 422.10)
Wiring Methods
Wiring methods must be suitable for the location (e.g., moisture resistance) and comply with Article 300, Chapter 3 requirements. (2023 NEC 300.1)
Mechanical (HVAC) Requirements
3 Rules
Heating & Cooling Source
The sunroom/four-season room must be provided with a heating system capable of maintaining a minimum indoor temperature of 68°F (20°C) at a point 3 feet above the floor and 2 feet from the exterior walls. Cooling is optional but must meet energy code if installed. (2024 IRC M1401.3)
Duct Sealing & Insulation
All ducts, air handlers, and filter boxes shall be sealed. Supply and return ducts in unconditioned spaces shall be insulated to a minimum of R-8. (2024 IRC N1103.3, M1601.3)
Ventilation
Mechanical ventilation, or natural ventilation (operable windows and doors) equivalent to 4% of the floor area, shall be provided. (2024 IRC R303.1, M1507.3)
Plumbing Requirements
2 Rules
New Plumbing Fixtures (If Applicable)
Any new plumbing fixtures (e.g., wet bar, sink) shall comply with the Illinois Plumbing Code for water supply, drainage, venting, and fixture requirements. (Illinois Plumbing Code 89 Ill. Adm. Code 890.300, 890.400, 890.700)
Backflow Prevention
Appropriate backflow prevention devices are required for any connections to the potable water supply that could pose a cross-connection hazard. (Illinois Plumbing Code 89 Ill. Adm. Code 890.1130)
