18102010

Hebel Wall Systems, what are they..

Most people have not heard of AAC blocks or similar 'specialized' building systems. They are most usually familiar with brick or wood construction.

Autoclaved Aerated Concrete (AAC) is a form of concrete that is literally 'bubbled concrete' cast into a form; usually as a large brick but can often be whole floor or wall sections. This material has the following properties:

• Light weight when compared to normal bricks
• High R-Value, so has a good ability to insulate against heat and cold
• High fire rating, both due to the high R-Value and concrete based construction.
• Low sound transmission.
  

Although AAC on its own does have some disadvantages compared to brick or wood constructions:

• Lower direct load capacity - i.e. cannot be really used to support structural loads, so some other building element needs to carry the load for them (i.e. a steel frame or suspended flooring). Although this being said Hebel do produce the PowerBlock system that claims to be load bearing in a certain configuration.
  
• Low impact resistance - basically they break easily, so need to be 'wrapped' by structure that provides impact resistance.
• Needs specialized glues and associated construction techniques.
• Low intrinsic thermal mass - i.e. you cannot use AAC as part of a trombe wall or as part of the aggregate whole house thermal mass.
  

This been said; if the building is completely new and is of yet not built; this could be a viable option for you if you are looking to:

1. Reduce you heating and cooling costs; i.e. you live in an environment where the temperature is constantly outside of the 'comfort' range;
2. You need sound isolation from the external environment (i.e. major road close by).

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