Characteristics of autoclaved aerated concrete

Autoclaved aerated concrete combines insulation and structural capability in one material for walls, floors, and roofs. Its light weight/cellular properties make it easy to cut, shave, and shape, accept nails and screws readily, and allow it to be routed to create chases for electrical conduits and smaller-diameter plumbing runs. This gives it design and construction flexibility, and the ability to make easy adjustments in the field.

Durability and dimensional stability. A cement-based material, AAC resists water, rot, mold, mildew, and insects. Units are precisely shaped and conform to tight tolerances.

Fire resistance is excellent, with eight inch thick AAC achieving a four-hour rating (actual performance exceeds that and meets test requirements for up to eight hours). And because it is noncombustible, it will not burn or give off toxic fumes.

The light weight means that R-values for AAC are comparable to conventional frame walls, but they have higher thermal mass, provide air tightness, and as just noted, are not combustible. That light weight also gives a high sound reduction for privacy, both from outside noises and from other rooms when used as interior partition walls.

But the material does have some limitations. It is not as widely available as most concrete products, though it can be shipped anywhere. If it has to be shipped, its light weight is advantageous. Because it is lower strength than most concrete products or systems, in load-bearing applications, it must typically be reinforced. It also requires a protective finish since the material is porous and would deteriorate if left exposed.