Insulation and Roof Replacements

When existing roofs (that are part of the building’s thermal envelope) are removed and replaced and when the roof assembly includes above-deck insulation, the energy code now requires that the insulation levels comply with the requirements for new construction, according to a proposal approved by International Code Council at public comment hearings held in October 2013.

This high-performance roof system was recently installed on a high school north of Chicago. It features two layers of 3-inch 25-psi, double-coated fiberglass-faced polyisocyanurate insulation set in bead-foam adhesive at 4 inches on center, weighted with five 5-gallon pails of adhesive per 4- by 4-foot board to ensure a positive bond into the bead foam until set. PHOTO: Hutchinson Design Group LLC

This high-performance roof system was recently installed on a high school north of Chicago. It features two layers of 3-inch 25-psi, double-coated fiberglass-faced polyisocyanurate insulation set in bead-foam adhesive at 4 inches on center, weighted with five 5-gallon pails of adhesive per 4- by 4-foot board to ensure a positive bond into the bead foam until set. PHOTO: Hutchinson Design Group LLC

As a result of this proposal approval, the 2015 International Energy Conservation Code (IECC) provides new language that provides clear unambiguous direction on how the energy code provisions apply to roof repair, roof recover and roof replacement.

Until this update there was a great deal of confusion given the various terms—such as reroofing, roof repair, roof recover and roof replacement—used to describe roofing projects on existing buildings in the International Building Code and the IECC. The clarification will help to mitigate this confusion.

Numerous studies have demonstrated the energy savings provided by a well-insulated roofing system. It is critical to minimize energy losses and upgrade insulation levels when roofs are replaced to comply with code requirements for new construction.

Each year about 2.5 billion square feet of roof coverings are installed on existing buildings and the opportunity to upgrade the insulation levels on these roof systems occurs just once in several decades when the roof is replaced or even longer when existing roofs are “recovered”. Until recently this requirement was prescribed using vague and confusing language, as noted.

Moving forward the IECC will use the same definitions found in the International Building code:

  • Reroofing: The process of recovering or replacing an existing roof covering. See “Roof Recover” and “Roof Replacement”.
  • Roof Recover: The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering.
  • Roof Replacement: The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.
  • Roof Repair: Reconstruction or renewal of any part of an existing roof for the purposes of its maintenance.

A survey of building departments in many states and regions in the U.S. found that online roofing permit application forms rarely included any information on the energy code and required insulation levels. With the changes to the 2015 IECC, it will be easier for building departments to correlate the building code and energy code requirements for roof replacements.

The clarification to the 2015 IECC makes the code easier to interpret and enforce. Along the way, it will help ensure that the opportunity to save energy when replacing roofs is not lost.

Another benefit of this update is that the exemption for roof repair is now clearly defined making it easier for building owners and roofing contractors to perform routine maintenance without triggering energy-efficiency upgrades, which would add costs.

About Jared O. Blum

Jared O. Blum is president of the Polyisocyanurate Insulation Manufacturers Association, Bethesda, Md.

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