Exterior Porches & Screen Rooms

Applicable Codes:
2024 International Residential Code
2023 National Electrical Code

Please submit the following information:

1. Legal Plat of Survey at original scale with the following information indicated:
   1. Proposed porch drawn to scale at the proposed location.
   2. The dimensions from the proposed porch to the adjacent lot lines and any accessory structures.
   3. The electric meter location, the electric service line path, and if the service is overhead or underground.
2. Architectural Plans that include:
   1. Plan view.
   2. Cross section, inclusive of piers/footings.
   3. Stair details.
   4. If the porch is a roofed structure, plans will need to be signed and sealed by a licensed professional.
   5. If electrical is included, a line diagram with the location of fixtures/receptacles and the location the electric is being pulled from.
3. Approval letter from the homeowner’s association if the porch is proposed to be installed in a townhome or condo.

Architectural Plan Requirements

Please submit architectural style plans that include the following information listed below:

1. Plan View - Must include the following information:

   • Foundation/Pier location, dimensions/diameters of footings, and distances to adjacent piers or from building.
   • Ledger board size, bolt type, bolt size, and spacing/pattern, location, number, and specification of lateral load devices.
   • Floor joist size, spacing, and span between bearing points.
   • Ceiling joist size, spacing, and span between bearing points.
   • Rafter size, spacing, and span between bearing points.
   • Beam sizes, spans, and cantilever dimensions.

2. Cross Section - Must include the following information:

   • Pier diameters and depth below grade.
   • Post sizes and method of connection to both beams and piers.
   • Beam sizes and specific method of attachment to posts (beams must bear on top of posts).
   • Ledger board size, flashing detail, bolt type, bolt size and spacing, location, and specific brand/model of lateral load devices.
   • Floor Joist sizes, spacing, span, and joist hanger locations (if applicable).
   • Ceiling Joist sizes, spacing, span, and joist hanger locations (if applicable).
   • Rafter sizes, spacing, span, and wind uplift clip locations (if applicable).
   • Roofing materials and specifications.
   • Decking material specifications.
   • Guardrail height and intermediate rail spacing.
   • Height of deck from grade to walking surface (indicate for all levels if multiple-level deck).

3. Stair Details - Must include the following information:

   • Riser height (maximum 7-3/4”) and tread depth (10” minimum measured from the nosing of the treads).
   • Guardrail details (minimum 36” in height, spindles spaced so that a 4” sphere cannot pass through).
   • Stair handrail details - must be 34”-38” above the nosing of the treads, extend the entire length of the stair run, and must comply with the graspability requirements.
   • Minimum 36” width for the stairway.

Note: Where special conditions exist, the building official is authorized to require additional construction documents to be prepared by an Illinois-licensed design professional.

Significant Building Code Requirements

WPorches are to be constructed to the requirements found in the 2024 International Residential Code. Here are some of the codes that pertain to porch construction:

1. Foundation Requirements

   • Foundations must be a minimum of 42 inches below grade.
   • Foundations must be supported either by undisturbed soil or engineered fill.
   • The diameter and spacing of the proposed piers shall be capable of properly carrying and conveying all imposed loads to the soil. The pier sizes shall be determined in accordance with the requirements of the 2024 International Residential Code. If piers are being used to support a roofed structure, the plans must be prepared, signed, and sealed by an Illinois-licensed design professional.

2. Framing Requirements

   • All lumber utilized in the construction of the proposed deck must be pressure-treated lumber, naturally durable lumber, naturally decay-resistant lumber, or other material as approved by the Building Official.
   • Beams shall be allowed to cantilever at each end up to one-fourth of the allowable beam span.
   • The ends of beams shall have not less than 1-1/2” of bearing on wood or metal and not less than 3” of bearing on load-bearing masonry or concrete for the entire width of the beam.
   • Floor joist spans of 8’-0” or more require solid bridging at joist midspan (Wheaton Ordinance).
   • Deck posts are to be sized per code and connected to concrete footings by manufactured connectors designed for that application, and provide lateral restraint.
   • Beams must be positively anchored to the deck posts by an approved manufactured connector.

3. Ledger Board Requirements

   • Deck Ledger Boards must be a minimum of a 2x8 pressure-treated, No. 2 grade or better, lumber.
   • The ledger board cannot support any concentrated loads from beams or girders.
   • Ledger boards cannot be supported on stone or masonry veneer.
   • The bolting of a ledger board must be as per code. If engineered fasteners are to be used, they must be installed per the manufacturer's installation specifications, and those specifications must be present on site at the time of inspection.

4. Hardware Coatings

   • All fasteners, flashing, or other metal hardware that is to come into contact with any ACQ-treated lumber must be of hot-dipped galvanized material. Hot-dipped galvanized fasteners shall meet ASTM A153.
   • Hot-dipped galvanized connectors shall meet ASTM A653, class G185 sheet with 1.85 ounces of zinc coating per square foot minimum.
   • Fasteners and connectors used together should be of the same type of material.

5. Stairs

   • Stairs shall be a minimum of 36” in clear width between guardrails (31-1/2” minimum from guardrail to required handrail).
   • The maximum stair riser height is 7-3/4”.
   • The minimum tread depth is 10” (measured from nosing to nosing).
   • Guardrails are required if the stairs exceed 30” above grade.
   • Graspable handrails are required for each flight of stairs with four or more risers.

6. Guardrails

   • Guardrails are required for walking surfaces that are located more than 30” above the floor or grade.
   • Guardrails must be a minimum of 36” in height (above the adjacent walking surface or the line connecting the nosings).
   • Guardrail openings shall not allow the passage of a sphere 4” in diameter.
   • Stair Guardrails shall be a minimum of 34” above the line connecting the nosing of the treads.
   • Stair Guardrail triangular openings formed by the tread, riser, and bottom rail shall not allow the passage of a sphere 6” in diameter.
   • If the top of the stair guardrail is to be used as a graspable handrail, then the top of the guardrail must be between 34”-38” above the line connecting the nosing of the treads.

7. Graspable Handrails

   • Handrails must be installed between 34” and 38” above the nosing of the treads.
   • Handrails shall not project more than 4 1/2” into the stairway or ramp.
   • Handrails must have a minimum clearance of 1 1/2” between the handrail and the wall.
   • Handrails must be continuous for the entire flight of stairs or ramp, beginning from a point directly above the top riser of the flight and ending at a point directly above the lowest riser of the flight.
   • Handrails with a circular cross-section shall have an outside diameter of not less than 1-1/4” and not greater than 2”.
   • Handrails that are not circular shall have a perimeter of not less than 4” and not greater than 6-1/4” with a cross-section of not more than 2-1/4”.
   • Handrails that are not circular with a perimeter greater than 6-1/4” shall comply with Type II handrail requirements found in the 2024 International Residential Code.

8. Roofed Structures

   • Overhead structural framing must comply with the requirements found in Chapter 8 (Roof-Ceiling Construction) of the 2024 International Residential Code. This applies to all structural elements, including but not limited to headers, rafters, ceiling joists, and all supporting elements.
     For details, please use the following link:
     https://codes.iccsafe.org/content/IRC2024P2/chapter-8-roof-ceiling-construction#IRC2024P2_Pt03_Ch08
   • All roofs and subsequent structural support of the roof must be capable of accommodating all imposed loads and properly transmitting the imposed loads to the supporting structural elements.
   • Any roof loads that are to be supported by piers must have a design that is prepared, signed, and sealed by an Illinois-registered design professional.

9. Electrical Installations

   • All electrical installations must comply with the requirements found in the 2023 National Electrical Code.
   • All porches shall have at least one GFCI receptacle located not more than 6’-6” above the balcony, deck, or porch walking surface (Note - Porches with solid perimeter walls will need receptacle spacing as required per code).
   • At least one lighting outlet controlled by a listed wall-mounted control device shall be installed to provide illumination on the exterior side of each outdoor egress door serving a porch.
   • Exterior stairways must be properly illuminated.