International Building Code 1510.1
General. Materials and methods of application used for
recovering or replacing an existing roof covering shall comply
with the requirements of Chapter 15.
Exception: Reroofing shall not be required to meet the minimum
design slope requirement of one-quarter unit vertical
in 12 units horizontal (2-percent slope) in Section 1507 for
roofs that provide positive roof drainage.
International Building Code 1510.2
Structural and construction loads. Structural roof
components shall be capable of supporting the roof-covering
system and the material and equipment loads that will be
encountered during installation of the system.
International Building Code 1510.3
Recovering versus replacement. New roof coverings
shall not be installed without first removing all existing layers
of roof coverings where any of the following conditions occur:
1. Where the existing roof or roof covering is water soaked
or has deteriorated to the point that the existing roof or
roof covering is not adequate as a base for additional
roofing.
2. Where the existing roof covering is wood shake, slate,
clay, cement or asbestos-cement tile.
3. Where the existing roof has two or more applications of
any type of roof covering.
Exceptions:
1. Complete and separate roofing systems, such as
standing-seam metal roof systems, that are designed
to transmit the roof loads directly to the building’s
structural system and that do not rely on existing roofs
and roof coverings for support, shall not require the
removal of existing roof coverings.
2. Metal panel, metal shingle and concrete and clay tile
roof coverings shall be permitted to be installed over
existing wood shake roofs when applied in accordance
with Section 1510.4.
3. The application of a new protective coating over an
existing spray polyurethane foam roofing system
shall be permitted without tear-off of existing roof
coverings.
International Building Code 1510.4
Roof recovering. Where the application of a new roof
covering over wood shingle or shake roofs creates a combustible
concealed space, the entire existing surface shall be covered
with gypsum board, mineral fiber, glass fiber or other approved
materials securely fastened in place.
International Building Code 1510.5
Reinstallation of materials. Existing slate, clay or
cement tile shall be permitted for reinstallation, except that
damaged, cracked or broken slate or tile shall not be reinstalled.
Existing vent flashing, metal edgings, drain outlets, collars and
metal counterflashings shall not be reinstalled where rusted,
damaged or deteriorated. Aggregate surfacing materials shall
not be reinstalled.
International Building Code 1510.6
Flashings. Flashings shall be reconstructed in accordance
with approved manufacturer’s installation instructions.
Metal flashing to which bituminous materials are to be adhered
shall be prim ed prior to installation.