Reroof Of Structures
Reroofing FAQ:
Guides for Owner-Builders

One of the most costly home maintenance tasks that homeowners may face is the replacement of the roof of their home. The installation of roofs and the reroofing of buildings is governed by the provisions of the California Building Code and the Manufacturer's written installation instructions. It is important that the procedures for reroofing, as stipulated by the California Building Code and Manufacturer Specifications, are followed by the homeowner or contractor to realize the maximum number of years of roof protection and safety to the home. This may answer many reroofing questions that are frequently asked by homeowners.
How is the need for a new roof determined?
The most obvious indication for the need of a new roof is the leaking of water in several locations, or if the roof is 20 years old or older. Many times a roof's life can be extended temporarily through repairs to the leaking area; however, the final decision to replace the roof should be made with the assistance and opinion of one or more local licensed roofing contractors who are experienced in this field. Licensed roofing contractors are listed in the local telephone directory. The contractor will inspect for blocked gutters that can cause the water to back up under the shingles and cause rot, and will look for worn-out and broken shingles and shakes. At the same time the contractor will check for rusted and loose flashing which can cause water leaks and fungus/moss growth which can cause decay and deterioration.
Why is a building permit required to reroof a structure?
Building permits and the procedure for applying new roofs and reroofing is covered in the California Building Code.

Before a reroofing permit is issued, the specifications for the roof are checked by the Building Division to insure that the roofing materials and application comply with Building Code standards and the Manufacturer's installation requirements.
Is it necessary to hire a roofing contractor or can the homeowner replace a roof?
Many homeowners choose to reroof their own homes to save the costs of labor. There are provisions in the building code that allow for this practice. The procedures for reroofing remain the same whether a homeowner applies the roof or if a roofing contractors is hired to do the work. The building inspector, through the inspection process, will inspect the roof for proper application in accordance with Building Code standards and Manufacturer's recommendations regardless of who installs it.
Can a new roof covering be installed over an existing roof?
The building official may permit the re-covering of existing roofing based on the condition of the roof, product manufacturers installation instructions, and the type of roof to be applied if the following general rules are applied:

Built up roofs:
Built up roof covering shall be completely removed before applying the new roof covering.

The Building Official may allow existing roof coverings to remain when inspection reveals all of the following conditions:
  1. That the roof structure is sufficient to sustain the weight of the additional dead load of the roof covering.
  2. There is not more than one existing roof covering on the structure.
  3. The existing roof covering is securely attached to the deck.
  4. The roof is structurally sound.
  5. The existing insulation (if installed) is not water soaked.

Asphalt Shingles:
No more than two overlays of asphalt shingles shall be applied over one existing asphalt shingle roof or wood shingles.

Wood Shakes:
New roof covering shall not be applied over an existing shake roof unless the new roof covering is a special type approved by the International Code Council (ICC). One overlay of wood shakes can be applied over an existing asphalt or wood shingle roof.

Wood Shingles:
Not more than one overlay of wood shingles shall be applied over existing wood shingles.

Tile Roofs:
Tile roofs may be applied over roof coverings when approved by the Building Official and the manufacturer of the new roofing material and substantiated by structural data indicating that the existing roof framing system is adequate to support the additional weight of the tile covering.
How can a reputable roofing contractor be located?
There are many local reputable roofing contractors. Roofing contractors are licensed by the Contractor's State License Board, are bonded and carry workman's compensation insurance for their employees. When a contractor is selected, ask for references and investigate them. Ask to see a copy of the Contractor's Warranty. Check with Contractor's State License Board and the Better Business Bureau for any complaints against the company. The Contractor's State License Board can be reached at (800) 321-2752.
Who is responsible for obtaining the building permit?
Reroof permits can be obtained by the homeowner or a licensed contractor. It is a violation of state law if a contractor commences a reroof project without first obtaining a permit. The homeowner can take out the permit for the contractor; however, this practice is not recommended. The owner of the property is the person who is ultimately responsible for insuring that a reroof permit is issued.
Is a permit required to replace some missing or broken shingles or shakes?
If minor repairs are made to roofs, it is considered a roof maintenance item and a permit is not required. However; when large sections of roof need to be replaced, it is considered a reroof and a permit is required even though the entire roof is not being reroofed.
Does the new roof need to be inspected by the Solano County Building Division?
The Solano County Building Division inspects all reroof projects for which a building permit is issued. Built-up roofs are inspected after the roofing is torn off and all rotted or damaged roof has been removed and replaced.

Shake and shingle roofs are inspected after the existing roof has been removed and the new sheathing has been nailed. Metal roofs are inspected after the installation of the nailing battens. All of the roofs require a final inspection upon completion of the work. It is the responsibility of the home-owner or the contractor to insure that all inspections have been made including the final inspection.
If the roof is replaced with shakes, must they be fire retardant?
In late 1994 the Board of Supervisors passed an ordinance stating that all shake roofs installed after that date shall be fire-retardant treated class B and of a type certified by an approved testing agency.
Do the flashings, gutters and roof jacks need to be replaced?
On a built up roof, vent flashings, metal edgings, drain outlets, metal counterflashing shall be removed and cleaned. Rusted metal shall be replaced. The metal shall be painted with primer prior to installation. On a shingle or shake roof, rusted or damaged flashing, vent caps and metal edgings shall be replaced with new materials as necessary.
Can shingles replace tar and gravel on a roof that is flat or with a slight slope?
The Building Code states that asphalt shingles are not allowed on slopes less than 2 inches of vertical rise for every horizontal foot of run of the rafter. For asphalt shingles installed on slopes of 2:12 to less then 4:12 the shingles must be self-sealing and installed with 2 layers of type 15 felt underlayment. Wood shingles are not permitted below 4:12.
What maintenance is required for the new roof?
Inspect the roof at least twice a year. Clean the roof drains of leaves and debris which could plug roof drains. Notify the roofing contractor if a leak occurs. Do not allow foot traffic on the roof in very cold or very hot weather.
If a problem occurs with the new roof, who does the homeowner contact?
If a licensed contractor installed the roof, the roof should be covered by a warranty. If the contractor does not make corrections or repairs to the roof, then the Contractor's State License Board should be notified.
Important Numbers
Department of Resource Management
675 Texas Street, Suite 5500, Fairfield
Building/Planning/Health Divisions (707) 784-6765
Building Inspection request line (707) 784-4750