courtesy U.S. Department of Energy

The 2009 International Energy Conservation Code (IECC) and the 2009 International Residential Code (IRC) have several new mandatory requirements for air sealing in new construction and additions.

Note that these codes apply to new construction where adopted by local jurisdictions. In general, these requirements do not apply to retrofit projects unless the project adds living space to the building or changes the building’s energy load. The existing, unaltered portions of the structure are not required to comply with all of the requirements of the 2009 IECC or IRC.

However, any remodeling work that intends to achieve increased levels of building performance should address air sealing — a high-value way to increase efficiency in existing homes.

New Guidelines

The U.S. Department of Energy’s Building America program has recently developed an air sealing guide for both contractors and consumers. The guide is intended to help contractors explain the value of air sealing to their customers, address important issues associated with air sealing (including ventilation requirements), and to provide technical guidance on key areas that are often difficult to address.

The following checklist and graphic are from Volume 10 in the Building America Best Practices Series “Retrofit Techniques & Technologies: Air Sealing: A Guide for Contractors to Share with Homeowners,” available here [PDF].

Air Sealing List

Air Barrier Completion Guidelines

1. Air barrier and thermal barrier alignment: Air barrier is in alignment with the thermal barrier (insulation).

2. Attic air sealing: Top plates and wall-to-ceiling connections are sealed.

3. Attic kneewalls: Air barrier is installed at the insulated boundary (kneewall transition or roof, as appropriate).

4. Duct shaft/piping shaft and penetrations: Openings from attic to conditioned space are sealed.

5. Dropped ceiling/soffit: Air barrier is fully aligned with insulation; all gaps are fully sealed.

6. Staircase framing at exterior wall/attic: Air barrier is fully aligned with insulation; all gaps are fully sealed.

7. Porch roof: Air barrier is installed at the intersection of the porch roof and exterior wall.

8. Flue or chimney shaft: Opening around flue is closed with flashing and any remaining gaps are sealed with fire-rated caulk or sealant.

9. Attic access/pull-down stair: Attic access panel or drop-down stair is fully gasketed for an air-tight fit.

10. Recessed lighting: Fixtures are provided with air-tight assembly or covering.

11. Ducts: All ducts should be sealed, especially in attics, vented crawlspaces, and rim areas.

12. Whole-house fan penetration at attic: An insulated cover is provided that is gasketed or sealed to the opening from either the attic side or ceiling side of the fan.

13. Exterior walls: Service penetrations are sealed and air sealing is in place behind or around shower/tub enclosures, electrical boxes, switches, and outlets on exterior walls.

14. Fireplace wall: Air sealing is completed in framed shaft behind the fireplace or at fireplace surround.

15. Garage/living space walls: Air sealing is completed between garage and living space. Pass-through door is weather stripped.

16. Cantilevered floor: Cantilevered floors are air sealed and insulated at perimeter or joist transition.

17. Rim joists, sill plate, foundation, and floor: Rim joists are insulated and include an air barrier. Junction of foundation and sill plate is sealed. Penetrations through the bottom plate are sealed. All leaks at foundations, floor joists, and floor penetrations are sealed. Exposed earth in crawlspace is covered with Class I vapor retarder overlapped and taped at seams.

18. Windows and doors: Space between window/door jambs and framing is sealed.

19. Common walls between attached dwelling units: The gap between a gypsum shaft wall (i.e., common wall) and the structural framing between units is sealed.

—The Department of Energy seeks to offer comprehensive, whole-house technical information to the industry and consumers to encourage energy-efficient remodeling and retrofit practices. Click here for a variety of resources, including case studies of successful retrofits in all climate zones, energy code and tax incentive information, and more.