Low to Moderate. Requires significant expertise in roofing, structural carpentry, flashing systems, and energy code compliance. Incorrect installation can lead to severe water damage, structural compromises, and energy inefficiency. Professional installation is highly recommended due to DuPage County's demanding climate and code adherence.
Skylight installation involves critical structural modifications, roofing integrity, intricate weatherproofing (flashing), compliance with energy codes for Climate Zone 5, and potential electrical work for motorized units. DuPage County's freeze-thaw cycles and snow load demand stringent attention to detail and material selection to prevent leaks and ensure long-term performance.
Project Guidelines & Rules
General Requirements & Permitting
3 Rules
Permit Application
Your local municipality's ordinances; IRC R105.1 (Permits required for alterations or new construction).
Plan Submission
Your local building department requirements; IRC R106.1 (Construction documents required for permit application).
Required Inspections
Your local building department requirements; IRC R109.1 (Specific inspections, e.g., framing, roofing, final).
Structural Framing & Support
3 Rules
Header Sizing and Support
IRC R802.9 (Headers for roof framing); IRC Table R802.4(1) or R802.4(2) (Rafter/joist framing, engineer-stamped plans for unusual conditions). Size headers to adequately support cut rafters or joists.
Trimmer Joists/Rafters
IRC R802.9; IRC R802.4.2 (Double trimmers required to support headers for openings greater than 4 feet).
Load Path Continuity
IRC R802.9 (Ensure load path continuity from roof to foundation).
Weather Protection & Roofing
4 Rules
Flashing Requirements
IRC R905.2.8.3 (Flashing at roof penetrations); Manufacturer's installation instructions (Crucial for warranty and performance, typically step-flashing and counter-flashing).
Underlayment Integration
IRC R905.1.1 (Underlayment types); IRC R905.2.7 (Underlayment for asphalt shingles). Ensure new underlayment integrates properly with existing roof underlayment for a continuous weather barrier.
Curb Construction (for curb-mounted skylights)
IRC R905.2.8.3 (Minimum 4-inch height for curbs above the roof plane, per manufacturer specifications).
Ice Barrier
IRC R905.1.2 (Ice barrier required in DuPage County due to Climate Zone 5). Install self-adhering polymer modified bitumen sheets at eaves and integrate around skylight perimeter for at least 24 inches up the roof from the wall line of the skylight opening.
Energy Efficiency & Glazing
3 Rules
U-factor and Solar Heat Gain Coefficient (SHGC)
IRC N1102.1.2 (Table N1102.1.2 for Climate Zone 5). Skylights must meet specific U-factor and SHGC values as specified by the manufacturer and verified by product labels (e.g., NFRC label).
Air Leakage
IRC N1102.4.1.1 (Skylights and other fenestration to be sealed against air leakage).
Insulation Requirements
IRC N1102.4.1.1 (Ensure continuous thermal envelope around skylight shaft/curb. Any framed opening or shaft must be insulated to meet wall or ceiling insulation requirements as applicable).
Electrical Requirements (for motorized units, blinds, or lighting)
5 Rules
Wiring Methods and Protection
2023 NEC Article 300 (Wiring methods); 2023 NEC Article 240 (Overcurrent protection); 2023 NEC 110.11 (Integrity of electrical equipment in wet/damp locations, especially for exterior wiring).
Grounding and Bonding
2023 NEC Article 250 (General requirements for grounding and bonding).
Wiring for Motors
2023 NEC Article 430 (Specific requirements for motors, including disconnects and overload protection).
Conductor Sizing
2023 NEC Article 310 (Conductors for general wiring, ensuring proper sizing for load).
Low Voltage Wiring (if applicable)
2023 NEC Article 725 (Class 1, 2, and 3 Remote-Control, Signaling, and Power-Limited Circuits).
Fall Protection & Job Site Safety
3 Rules
Ladder Safety
OSHA 1926 Subpart X (Stairways and Ladders); Ensure proper ladder setup and stability.
Roof Safety & Fall Protection
OSHA 1926 Subpart M (Fall Protection); Utilize guardrail systems, safety net systems, or personal fall arrest systems when working on roofs, especially near openings.
Opening Protection
OSHA 1926.501(b)(4) (Protection from falling through holes); Ensure roof openings are guarded or covered to prevent accidental falls during construction.
