Roofing Requirements

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Revised February 1, 2016

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In order to serve the City of Littleton citizens and roofing contractors, the following summarizes the most frequently asked questions regarding roofing requirements. 


The City of Littleton requires a permit for all new roof coverings and roofing repairs exceeding 100 square feet (1 roofing square) of roofing material.

A pre-roof inspection is required after the roof covering is removed and the new underlayment is installed. Finish materials cannot be installed.

Building Inspections The inspection will be scheduled for the next available day. Ladders must be provided by contractor and tied off.

Code Requirements

Reference chapters 8 and 9 of The International Residential Code (IRC), chapters 12 and 15 of The International Building Code (IBC), chapter 4 of The International Energy Conservation Code, and the amendments to the International Codes that apply to the insulation, roof venting and roof coverings of buildings.


Commercial Buildings shall have the minimum insulation required. Insulation above roof decking shall be a continuous R25. Insulation in an attic or closed cavity shall be an R38. 

Roof Ventilation

Enclosed attics and enclosed rafter spaces where a ceiling is directly applied to the underside of the rafter shall have cross ventilation. The minimum net free ventilating area shall be 1/150 square feet of the area of the vented space.

Drip Edge Metal

Drip edge shall be provided at eaves and gable ends of roofs. Drip edge shall extend a minimum of 0.25 inch below the roof sheathing and extend up the roof deck a minimum 2 inches onto the roof decking.

Ice Barrier

Ice barrier shall be used in lieu of normal underlayment and extend from the lowest edge of all roof surfaces to a point at least 24 inches inside of the building thermal envelope.

Flashing Requirements

  • Most neoprene plumbing vent flashings will have to be replaced due to deformities caused by exposure to the elements.
  • Rusted and/or damaged flashing, attic vents, furnace to fireplace vents are required to be replaced.
  • Flashing used for open valleys shall be a minimum 24-inches wide, 26-gage galvanized steel.
  • Flashing and counter flashings are required where the roof meets a vertical surface. Counter flashing may be omitted if the top edge of the wall flashing is covered with an approved exterior siding material.
Mineral-surfaced roll roofing

Mineral surfaced roll roofing is NOT allowed for single family, duplexes or townhomes.

Shake Shingles
Minimum #1 grade required.

Asphalt Shingles
  • Asphalt shingles shall comply with ASTM D 225 or ASTM D 3462 or ASTM D 3161 or ASTM D 7158 for wind resistance.
  • A minimum roof pitch of 2 units vertical to 12 units horizontal is required.
  • Roof slopes 2 units vertical in 12 units horizontal (2:12) to 4 units vertical in 12 units horizontal (4:12), double underlayment is required. Underlayment shall conform to ASTM D 226 Type I, commonly known as No. 15 asphalt felt.
  • Asphalt shingles shall be fastened to solidly sheathed roof decks. Solid sheathing is required if there are gaps ¼ inch or greater in the spaced decking.
  • Installation as per manufacture’s high wind application is required.
Mansard or High-Slope

Shingles are required to be fastened per manufacture’s installation instructions.


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