Quality insulation and air sealing enable you to maintain a comfortable indoor temperature and save heating/cooling costs while protecting your building from destructive moisture and keeping your indoor air free of related molds. There are many new advances in commercial building envelope systems that significantly improve the overall thermal and moisture transfer properties of the exterior walls, windows, and roof. The key is to provide an adequate thermal break before the metal or wood framing and to properly air seal.

The insulating value of a material depends on the air space contained in it. If air can move through, the insulating value is diminished. Here's an overview of some options:

These are commonly used insulation materials. They're inexpensive and can be easy to install. However, they also are easy to install improperly, often being crammed in without being cut to size. As a result, insulation values are reduced and insulation gaps can occur. Fiberglass batts always should be cut to size, filling the framing cavity without any gaps or compressed sections. They also should be cut to accommodate all obstructions, such as plumbing and electrical.

An additional drawback of fiberglass insulation is its lack of inherent air-stopping ability. To be effective, it should be installed with rigid air-stopping materials (i.e. wood studs, sheetrock, plywood, OSB sheathing) surrounding the insulated cavity.

Can be blown into the attic for more uniform coverage around framing irregularities. Because it is loosely blown, though, its air-stopping ability is limited. For additional effectiveness, you should air-seal all electrical and plumbing penetrations, chases and other such holes with the appropriate sealing materials (i.e. foam, fire-rated caulk).

Can effectively insulate and air-seal walls and significantly reduce air leakage. Spray applied cellulose (recycled newspaper) is installed with a mist of water and allowed to dry before sheetrocking. Densepack cellulose is inserted through a tube into each building cavity and the dry cellulose is mixed with air to a density of at least 3.5 lbs./cu. ft.

A self-contained effective insulator and air-sealer. It adheres to rough, irregular surfaces as well as the underside of horizontal surfaces. A skilled installer has the proper tools to apply it. While the material costs are more, the labor savings can be significant and it's easy to visually verify an effective installation. It can also be used to address difficult air sealing areas, such as band joists in buildings with open web floor trusses and floor systems under parking garages and living spaces. It also works well as a retrofit insulation option for brick buildings.

The following is a list of some common air leakage points to seal in all buildings:

• All plumbing, electrical, electric box, duct penetrations in exterior walls and attic;
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• Any chases open to the attic;
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• The gap between the top plates of interior and exterior walls and ceiling sheetrock in the top story ;
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• Bottom edge of sheetrock sealed to subfloor or slab on exterior walls;
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• Window rough openings sealed with minimally expanding foam with bead size to seal gap between window frame and rough opening. Do not try to fill depth of gap!
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• Cantilevered floors;
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• Kneewalls in cape style buildings;
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• Band joist area in floor system;
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• Joints between existing buildings and additions;
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• Joints between modular buildings.

A building can't be too tight, but it can be under-ventilated. Get more information on effective mechanical ventilation.