---

What Requires a Permit?- Building Notes- Setbacks- House Permit- Deck Permit- Garage Permit- Inspection Regulations- Re-roofing Asphalt Shingles- Siding- Site Plans- Surveying- Contractors/Builders- Wood Decks

Reroofing Asphalt Shingles

OVERLAY OR TEAR-OFF?

The re-roofing of a structure having asphalt shingles may be accomplished by either adding an additional layer of asphalt shingles (up to two overlays are permitted over an original shingle roof) or completely removing the existing shingles, underlayment, flashing, etc. (tear-off) and then roofing as if new construction.

To assist in making the decision whether to overlay or tear-off, consider the following:

1. Check the framing beneath. It must be adequate to carry the additional weight of new materials plus the weight of roofers and their equipment.
2. Check the condition of the existing deck sheathing. It must be adequate for both support and anchorage for new roofing fasteners.
3. Check the condition of the roofing surface. If it is warped, curled, or badly weathered to the point where providing a level surface for the new material will be difficult, it should be removed. If the surface is defective to the point where it will not serve as underlayment, it should be removed.

1. For roof pitches of 2:12 to less than 4:12:
   Two layers of 15# felt applied shingle fashion. Starting with an 18-inch wide sheet and a 36-inch wide sheet over it at the eaves, each subsequent sheet shall be lapped 19 inches horizontally.
2. For roof pitches of 4:12 and over:
   One layer of 15# felt lapped 2 inches horizontally and 4 inches vertically.

1. For roof pitches of 2:12 to less than 4:12:
   Same as for UNDERLAYMENT, and additionally the two layers shall be solid cemented together with approved cementing material between the piles extending from eave up the roof to a line 24 inches inside the exterior wall line of the building. See Figure 2 on reverse side. Approved waterproofing underlayments are acceptable alternatives to this requirement.
   
2. For roof pitches of 4:12 and over:
   Same as for UNDERLAYMENT, and additionally install a strip of 50# smooth (no granules), coated roll roofing parallel to the eaves and extending to a line 12 inches inside the exterior wall line of the building. If a second flashing strip is required to reach that point, locate the lap in front of the exterior wall line. Overlap the flashings at least 2 inches and cement the horizontal joint over its entire length. End laps should be 12 inches and cemented. See figure 3 on reverse side. Approved waterproofing underlayments are acceptable alternatives to this requirement.

When existing flashing is no longer serviceable, valley flashing shall consist of not less than No. 28 galvanized sheet gauge corrosion resistant metal. The metal shall extend at least 8 inches from the center line each way. Sections of flashing shall have an end lap of not less than 4 inches. Alternatively, the valley shall consist of woven asphalt shingles applied in accordance with the manufacturer’s instructions.

VALLEY UNDERLAYMENT
(Tear-offs/reflashing only)

A 36 inch wide strip of 15# felt shall be centered in the valley on top of the underlayment required for the entire roof. For roof slopes of less than 7:12, the metal valley flashing underlayment shall be solid cemented to the roof underlayment. As an alternate to solid cementing, an approved waterproofing underlayment may be used.

OTHER FLASHING

All other flashing and roof vents shall be checked and if rusted or in bad condition shall be replaced. When replacement flashing is of metal it shall be of not less than No. 26 gauge corrosion-resistant metal.

ROOF AND SOFFIT VENTS

If necessary, additional roof and soffit vents shall be installed so that for every 300 square fee or roof or floor area there is at least one square foot of ventilation in the roof.