Background
Roof maintenance is an important element in the health and longevity of a building. Whether or not your project requires a building permit, building and energy code requirements must be met. This policy outlines the permitting and energy code requirements for roofing projects based on the type of roofing work being done.
Roof Recover
A roof recover is where a new layer of roofing material is installed over an existing roof covering without removing the existing roofing covering. In both commercial and residential buildings, no building permit is required unless the additional roofing material increases the total weight of the roof by more than 5 percent. In both commercial and residential buildings, there are no energy code requirements for a roof recover.
Roof Replacement
A roof replacement is where an existing roof is removed, damaged substrate is repaired, and a new roof is installed. Permitting and energy code requirement are noted below and depend on the scope of the work and the type of building.
Commercial Buildings
For commercial buildings (as defined in the WA State Energy Code, see below) a building permit is not required for a roof replacement project if the repaired or replaced substrate is limited to two (2) four-foot by eight-foot sheets of substrate/sheathing.
When insulation is entirely above the roof deck or the roof assembly has no existing insulation, the roof replacement work is required to provide the same level of insulation as is required for new construction (WSEC C503.3.1). This new insulation can either be provided within the roof assembly, or above the roof deck.
When insulation is within the roof cavity, and the roof cavity IS NOT exposed during construction, no new insulation is required (WSEC C503.1 Exception 4).
When insulation is within the roof cavity, and the roof cavity IS exposed during construction, the exposed cavity must be insulated to full depth with minimum R-3.0 per inch insulation or to what is required for new construction (WSEC C503.1 Exception 3). Note that if the roof assembly is vented, a gap must be maintained between the insulation and the sheathing to allow for air circulation per IBC Section 1202.2.
Residential Buildings
For residential buildings (as defined in the WA State Energy Code, see below) a building permit is not required for a roof replacement project if the repaired or replaced substrate is limited to five (5) four-foot by eight-foot sheets of substrate/sheathing.
When the insulation is within the roof cavity and the roof cavity IS NOT exposed during construction, no new insulation is required (WSEC R503.1.1 Exception 3).
When the insulation is within the roof cavity, and the roof cavity IS exposed during construction, the exposed cavity must be insulated to full depth with insulation (WSEC R503.1.1 Exception 2). Note that if the roof assembly is vented, a gap must be maintained between the insulation and the sheathing to allow for air circulation per IRC R806.3.
When there is no insulation in the roof cavity, and the sheathing or roof cavity are exposed, insulation must be provided either within the cavity or above the sheathing. If provided within the cavity, the cavity must be filled to full depth with insulation. Note that if the roof assembly is vented, a gap must be maintained between the insulation and the sheathing to allow for air circulation per IRC R806.3. If insulation is provided on top of the roof deck, that insulation thickness must meet the same requirements as for new construction.
Multi-Unit Residential Buildings
Washington State Legislature RCW Section 64.55 has requirements on permits for multi-unit residential buildings (as defined in RCW 64.55). Permits for “rehabilitative construction” must include building enclosure documents and a building enclosure inspection. Rehabilitative construction is any work on the building enclosure, including the roof, where the cost of the work is more than five percent of the assessed value of the building. Determination on the applicability of, and any items required by RCW 64.55 must occur prior to the issuance of any building permit for the roofing work.
Definitions
Commercial Building: All buildings not included in the definition of "Residential building."
Residential Building: Detached one- and two-family dwellings and multiple single-family dwellings (townhouses), Group R-3 buildings three stories or less in height above grade plane, and Group R-2 occupancy areas in buildings three stories or less in height above grade plane whose dwelling units are accessed directly from the exterior.