Residential RE-ROOFING Checklist & Guide for Asphalt Shingle applications
(2015 IRC requirements as amended by St. Louis County Ordinances for 1-& 2-Family Dwellings and Townhouses)
This RE-ROOFING Checklist is based on St. Louis County’s (SLCO) policies, construction codes amended and adopted by ordinance. See list below. It is not a substitute for those codes and ordinances, but serves as a guide to reading them. More information and explanation is provided in commentaries and interpretations published by St. Louis County and acknowledged code organizations.
RESIDENTIAL RE-ROOFING REQUIREMENTS
(Per the 2015 IRC as amended by St. Louis County Ordinances for 1-& 2-Family Dwellings and Townhouses)
List of Applicable Codes and Ordinances:
2015 International Residential Code (IRC) & Ordinance #27,654-Ch.1116 (“R” “G”, “N”, and “M” references and Appendix K - Sound Transmission)
2015 International Building Code (IBC) & Ordinance #27,654-Ch.1116\5 (“B” references).
2015 International Property Maintenance Code (IPMC) & Ord. #27,617-Ch.1110 (“PM” refs.).
For inquiries regarding the information provided in this guide, please contact:
St. Louis County Permit Processing (314) 615-5184
St. Louis County Zoning Review (314) 615-3763
St. Louis County Building Plan Review (314) 615-5485
Right-of-Way Owner State
(888) 275-6636 County
Municipality
(314) 615-8517
Call the project site’s Municipality
St. Louis County’s Municipal Contracts Matrix shows those municipalities that currently contract for its Code Enforcement services. The Matrix is on our web site at https://stlouiscountymo.gov/st-louis-county-departments/transportation-and-publicworks/residential-building/
For the electronic plan review, scan QR code or visit us online at https://stlouiscountymo.gov/st-louis-county-departments/transportation-and-publicworks/electronic-plan-review/
Sections from the Codes, their Referenced Standards, and St. Louis County Ordinances, are shown at ends of statements and are italicized in parentheses (.)
NOTICES Regarding Permits
• The applicant (property owner or the owner’s authorized agent) is responsible for contacting those applicable agencies that may be affected by the new work, or that may have legal oversight of the new work along with but separate from St. Louis County. Where requirements among the agencies conflict, the most restrictive shall govern the new work. Contact these agencies before beginning work approved under a permit issued by St. Louis County. Such agencies may include:
1. The project site’s Municipality;
2. The local Fire Protection District;
3. The Highway Department;
4. The Sewer District; and
5. Subdivision Trustees.
• A building permit is required to re-roof with asphalt shingles a 1-or 2-family attached dwelling or townhouse, where any of the following conditions are present:
1. Roof Slope is less than 4:12;
2. More than 25% of Roof Sheathing requires replacement;
3. Roof Cover proposed is a different material from the existing roof cover, such as replacing wood shingles with asphalt shingles; This is required regardless of the roof slope;
4. Wood structural panel sheathing is required to replace existing board sheathing, because the gaps between the boards exceed space limits of the Code.
• Notice: A building permit is not required to provide a like-for-like replacement of asphalt shingles on roofs having a 4:12 or greater slope. Please be aware any new work re-roofing not requiring a permit in St. Louis County’s jurisdiction must still comply with the requirements of St. Louis County Codes and Ordinances. However, the Code does require the work not requiring a permit must still be done in a manner that is not in violation of the provisions of the code (Refer to IBC Section 105.2 that is referenced through the IRC adopting ordinance). This means all work - with required permits, or with no permit required - must still be provided in compliance with IRC Reroofing Section R907.
• This checklist is not applicable to roof coverings other than asphalt shingles. Please see Chapter 9 of the 2015-IRC and St. Louis County Ordinances for requirements of other roof coverings.
• Notice: Manufacturer’s installation instructions and applicable code provisions: The 2015-IRC Reroofing Sub-Section R908.1-General points out other code requirements within IRC Chapter 9 Roof Assemblies as they relate to “materials and methods of application used for re-covering or replacing an existing roof covering”. Material requirements are found in IRC Section R904 and minimum requirements of application are found in IRC Section R905. Both of these sections reference the manufacturer’s installation instructions. Thus, along with the applicable code sections, the portions of the manufacturer’s installation instructions pertinent to “materials and methods of application of roof coverings” must be followed on reroofing projects. “Roof covering” provisions generally regulate the roof deck, roof slope, underlayment, roof covering materials used, flashing, application and attachment as they relate to weather protection
• Recovering vs. Replacement: 2015-IRC Section R908.3 requires all existing layers of roof coverings be removed down to the sheathing prior to applying a new roofing covering. The only exception is when there is only a single layer of existing roof covering and the roof covering and sheathing below provides an adequate base that is neither deteriorated or water soaked.
• Building permit issuance for the project does not authorize construction access to the work site. If the existing driveway entrance to the site is unavailable for construction access, the owner/ contractor shall apply for a permit to construct a temporary entrance from the owner of the Right-of-Way.
For the Re-Roofing permit, provide 1 of the following on the site plan:
1. Draw an arrow over the property’s existing driveway and pointing into the lot. Label the arrow location as “construction entrance”; OR
2. Draw an arrow over a proposed alternate access location pointing into the lot. Label the arrow location as “construction entrance”. Also provide note required on the site plan of “A separate special use permit for a construction entrance will be obtained from the street right-of-way owner before the start of construction access to the project site”.
• Structural alterations proposed to the existing building must be drawn and submitted in an electronic set properly sealed by a Missouri registered Design Professional. Please be aware properly sealed structural calculations may also be required by the Plan Reviewer, depending on the alterations proposed and adequacy and completeness of sealed drawings submitted.
• Only alterations as shown in approved and issued permit drawings shall be provided in the field If the Field Inspector finds otherwise, a separate permit application submitted with properly sealed structural drawings and calculations shall be required for review of the outside-work scope alterations.
• Properly sealed drawings means the first sheet of the electronic set submitted is electronically sealed, signed, dated by a Missouri registered engineer or architect, with subsequent sheets of set bearing the registered design professional’s electronic seal. The first sheet, or the title block of each sheet in set submitted, is to note the design professional’s business address and contact number, and is to also include the project address, owner name(s) and a description of the new work proposed. Any revisions to drawings are to be highlighted by clouding or by another easily recognized method.
• Properly sealed calculations means the cover sheet shall be electronically sealed, signed, dated by a Missouri registered professional engineer or architect, with pages sequentially number and totaled, and starting with the cover as page 1. The design professional shall include on the cover his/her contact number and business address, the project’s description of work, the project address and the property owner name(s); and shall provide in the calculations the Code Basis of Design.
• The Plan Reviewer may determine the proposed work, construction, or conditions require additional drawings and information be submitted to Code Enforcement-Plan Review for review, beyond the minimum submittal requirements noted in this Checklist.
Submittal Requirements:
Zoning Approval, Notes & Drawings
Submit the following drawings and documents with a permit application to RE-ROOF WITH ASPHALT SHINGLES a residence in Unincorporated St. Louis County, and in those Municipalities that contract with St. Louis County for Residential Code Enforcement Services. Specific Code and Ordinance Sections may be provided below in parentheses italicized (.) at the end of a statement.
• Electronic Building Permit Application filled out, signed and dated by the applicant.
• Electronic set of scaled, labeled, and dimensioned drawings and other documents as noted below (B107.2.1; SLCO Policy):
1. Site Plan with Zoning approval:
a. For properties in a Municipality, submit each site plan stamped, signed and dated by the Municipal Zoning officer, and submit the Zoning application receipt dated and signed-approved by the Zoning Officer.
b. For properties located in Unincorporated St. Louis County, submit site plans showing:
a. Lot configuration and building(s) located on the lot;
b. Highlight or label the building to receive re-roofing;
c. Building’s dimensioned distance from property line(s) may be required, if it appears close;
d. Note the lot number and subdivision name [SLCO Policy].
2. Roof Plan. Show and label roof ridges, roof-to-wall-and-chimney intersections, crickets and saddles, and mechanical and plumbing penetrations Key each to a section detail drawing
3. Section details of new work roofing installation and flashing assemblies required at roof ridges, valleys, roof-to-wall-and-chimney intersections, crickets and saddles, drip edges at rakes, at roof edges with gutters, and at mechanical and plumbing penetrations.
4. General notes of construction and material specifications, and/or 1 complete set of the roof manufacturer’s installation manual. It will be returned to the applicant at permit issuance
• See the example drawings at the end of this checklist for reference in completing your own project-specific drawings. The items below are St. Louis County Code and Ordinance requirements for Residential Re-Roofing that are to be provided in your drawings and notes.
Design, Construction & Finish Requirements
The following are minimum requirements of the Codes, Ordinances and Policies of St Louis County to be provided in Re-Roofing drawings submitted for a permit. Code and Ordinance Sections are in brackets [.].
• Roof Sheathing
1. Asphalt shingle roof covers shall be fastened to solidly sheathed decks
2. Acceptable existing sheathing conditions are as follows (R905.2.1; SLCO Policy):
a. Wood structural panel sheathing thickness and spans allowed by Code when the sheathing was installed, where not deteriorated, warped, cracked, or delaminated between supports.
b. Wood sheathing boards with maximum 1/2” gap between boards;
c. Wood sheathing boards with larger gaps that are overlaid with minimum 3/8” thick wood structural panel sheathing.
3. Where new work wood structural panel (plywood) sheathing is required, comply with the table below (R503.2.1.1; Table R503.2.1.1(1)):
ALLOWABLE SPANS & LOADS FOR WOOD STRUCTURAL PANEL ROOF SHEATHING
I. Loads in the Table above are based on a 10-psf dead load. If actual conditions have a greater dead load, reduce live loads accordingly.
II. Panels must be continuous over 2 or more spans with long dimensions perpendicular to supports. Spans shall be limited to values shown because of the possible effect of concentrated loads.
III. The table above applies to panels 24” and wider.
• Roof Underlayment
1. Minimum required underlayment is Type I (also called 15# specification felt) per ASTM D 226; D 1970; D 4869; or D 6757 (R905.1.1).
2. Minimum 1 layer of underlayment required on slopes 4:12 and greater. Apply underlayment shingle fashion, so it is parallel to and starting from the eave and is lapped 2”. Adequately fasten to hold the underlayment in place. End laps shall be 4” and offset 6’-0” (R905.1.1; Table 905.1.1(2)).
3. Minimum 2 layers of underlayment required on slopes of 2:12 to less than 4:12. Asphalt shingles are allowed on roof slopes 2:12 or greater. Starting at and parallel with the eaves, fasten a 19” strip of underlayment felt. Starting at the eave, apply 36” wide sheets of underlayment. Successive 36” wide sheets of underlayment shall overlap the previous 36” wide sheet by 19”. Adequately fasten underlayment to hold it in place (R905.1.1; R905.2; Table 905.1.1(2)).
4. Ice Barrier underlayment is not required (R905.1.2; SLCO Rev. Ord. Table R301.2(1)).
• Roof Cover
1. Class A, B, or C roofing is required where a roof edge is less than 3’-0” from a lot line (R902.1).
2. Replacement vs. Recover: Replacement requires existing layers of asphalt shingle roof coverings be removed down to the sheathing before the new roof cover of asphalt shingles is installed.
Exceptions:
a. Only 1 layer of roof cover exists, and it is not deteriorated or water soaked (R908.3.1.1-Items 1, 3).
b. The structural roof components are capable of supporting the dead load of 2 roof covers. Properly sealed structural calculations may be required by Building Plan Review on a case-bycase basis (R908.2; SLCO Policy)
• Valleys
1. Provide valley linings in accordance with the manufacturer's installation instructions and before the asphalt shingles are installed (SLCO Rev. Ord. R905.2.8.2).
2. Valley linings noted below are permitted (R903.2; SLCO Rev. Ord. R905.2.8.2):
a. Open valleys (valley lining exposed) lined with metal at least 24” wide each side and of any of the corrosion-resistant metals listed in the 2015-IRC Table R905.2.8.2. OR
b. Open valleys shall be lined with 2-plys of mineral surface roll roofing that complies with ASTM D 3909 or ASTM D 6380 Class M. The bottom layer shall be 18” and the top layer a minimum of 36” wide.
c. Closed valleys (valley covered with shingles) lined with 1-ply of smooth roll roofing compliant with ASTM D 6380, or 2-plys of smooth roll roofing compliant with ASTM D 226 Type I, ASTM D 4869 Type I or ASTM D 6757, and at least 36” wide. Valley lining as described in Item 2.a. or 2.b. above are permitted under shingles. Self-adhering polymer modified bitumen underlayment compliant with ASTM D 1970 is permitted in place of the lining material.
• Flashing & Drip Edge
1. Provide corrosion-resistant flashing at roof intersections, at changes in roof slope or direction at walls, sidewalls, and chimneys, around roof openings, and at abutments with porches and decks. Existing flashings in good condition may remain where their installation is consistent with the manufacturer’s installation instructions (R903.2; R905.28.3; R905.2.8.4; 908.6).
2. Sidewall flashing shall be step flashing (R905.2.8.3).
3. Drip edge is required at eaves and rakes of shingle roofs. Extend the drip edge minimum 2” onto roof sheathing and minimum 1/4” below the roof sheathing. Install roof underlayment over the drip edge along eaves and under the drip edge at rakes (R905.2.8.5).
• Roof Ventilation
1. With re-roofing, roof ventilation shall be verified as, or made compliant with, Section 806 of the 2015-IRC. Any existing ducts terminating in enclosed attic or rafter spaces shall be made to discharge directly to the exterior. Only bathroom exhaust ducts may terminate at the attic gable vent or soffit vent if they can be secured within 6” of the vent (R908.3; SLCO Rev. Ord. R908.7).
2. Enclosed attic and rafter spaces shall have cross-ventilation to allow heat and moisture to escape the attic space as follows (R806; R806.2):
a. The minimum net free ventilation area shall be 1-sq. ft. for every 150-sq. ft of attic area.
b. The ventilation requirement may also be 1-sq. ft. of vent area for every 300-sq. ft of attic area with the following provided:
1) Installation of a Class I or II vapor retarder on the warm-in-winter side of the ceiling and;
2) Minimum 40% and maximum 50% of ventilation is provided in the not more than 3-ft. below the ridge or the highest point of the space, and;
3) The remainder of the ventilation provided at eave or cornice vents.
3. In vented insulated attics, a minimum 1’’ clear continuous air passage is to be maintained between the top of the insulation and the underside of roof sheathing, so the air passage extends to vents at the roof ridge. Provide baffles adjacent to the soffit or eave vents, and place the baffles over the top of the insulation to maintain the 1” clear continuous air passage. (R806.3; N1102.2.3)
Notice: The preceding requirements apply to most simple projects Re-Roofing Asphalt Shingles on Sloped Roofs. However, the Plan Reviewer may determine the actual new work shown in the drawings requires additional information be submitted to verify code compliance of the new work proposed. The above requirements are based on the construction codes in effect at the time this checklist was last updated. Please be aware St. Louis County Code Enforcement updates its construction codes every few years.
