I have chosen the materials and building methods that we practice in response to our many years in restoration of historical houses and our experience in remedial construction of existing modern construction.  In 1995 I started exploring ways in which we could design and build custom homes to overcome the typical issues, with which we struggle in trying to find permanent solutions for houses that have had continuous high maintenance as a result of poor design, workmanship and/or materials that do not prove to be reliable over the long haul.

The primary building material that we have found that best meets the criteria for low maintenance and high energy efficiency for long term reliability is Autoclaved Aerated Concrete.  I was first attracted to this material, primarily from my historical perspective.  It has proven itself to perform well as a high thermal mass, energy efficient and low maintenance product in many climates and conditions for nearly a century.  It was first developed in Sweden in the early part of the 20th Century and was further developed in Germany.  There are actually more houses and buildings built with Autoclaved Aerated Concrete (AAC) throughout the world, than there are structures built with wood frame construction.

1. It is completely resistant to the infestation of insects such as termites and carpenter ants, which are particularly a serious structural threat to building built with stick frame construction here in the Southeast.


2. It is completely fireproof and not structurally compromised under intense heat exposure.  Insurance company are now recognizing this fact and offering discounts on premiums for houses built with AAC.


3. Unlike most high thermal mass products for construction such as polystyrene Insulated Concrete Forms or foam structural panels, AAC has a high thermal mass necessary for an energy efficient envelope and yet is a permeable material.  The advantage of this especially for our high relative humidity climate is that it is a breathable material.  It is water resistant because of its solid mass and because it percolates very slowly, but it also allows condensation moisture and vapors to wick through to the outside.  This is very important in a high thermal mass structure.  It allows fresh air to breath through its walls, but it also allows dangerous gases to escape through the walls as well.


4. Its high thermal mass is created by a chemical reaction that takes place when the concrete is batched, which captures thousands of tiny air pockets in the product.  This is what makes it fireproof, highly energy efficient and a great sound isolator.


5. It is a completely renewable resource material as well as a completely recycled material.  When the concrete is cut to make blocks and building panels the dust is captured and reused for making mortar, stucco and for making new concrete materials.


6. The AAC blocks dimensionally accurate because they are wire cut and thus are put together with a thin bed mortar, which literally sucks the blocks together.  This makes the joints the strongest part of the structure.  When the entire structure is tied together it becomes a monolithic unit.


7. As a monolithic structure it can better withstand the rigors of storms.  Most damaged caused by tornadoes and hurricanes is from the objects that are thrown against a house or building.  Unlike other structures such as framed construction or even case in place concrete AAC has proven to withstand these impacts much better.  AAC can absorb most impacts or even be impelled by objects and still not be structurally compromised.  Cast in place concrete as in standard form construction or Insulated Concrete Form construction when impacted by flying debris, because of its rigidity, that impact is transferred throughout the structure often causing catastrophic damage to the structure.  However AAC is softer than regular concrete so often it will absorb the impact or be impelled, so the damage is sustained only at the immediate point of impact.  Most of the time the repair for AAC concrete after a storm is simply cutting out the damaged area and replacing it with new block, so the cost is much less.

8. AAC is a very workable material giving the designer and builder many opportunities to do unique shapes structurally and aesthetically.  The material can be cut in almost any shape with a special band saw.  It can be drilled, shaped with a router, channeled with a router and can even receive standard course thread screws.   This also makes it very easy to run electrical lines, plumbing and other mechanical components through out the structure.


9. I am often ask how does building with AAC compare in cost to standard stick construction.  Of course they are speaking about standard 4 inch framed walls which have a defined thermal rating of R-13.  AAC residential walls have a standard 8 inch thick wall, which has a solid thermal mass rating without any coating or siding applied of R-30.  Also available are 10 inch with an R-38 value or 12 inch with an R-46 wall value can be built with AAC.  The correct answer to the inquirers question is that if there really were an equivalence to be built with frame construction it would cost an average of 3 times as much as it would cost to build with AAC.  It typically cost 15-30% more to build with AAC as with standard 2x4 stick construction.


10. AAC construction is a natural material and a natural insulator thus eliminating the need for many of the harm components that are standard in composition stick construction.  The resident is not continuously exposed to the toxic dust of fiberglass insulation or the formaldehyde gases put off from many manufactured products such as OSB board.  So an AAC house is a healthy home environment especially for those residents that suffer from allergies or respiratory diseases.  Furthermore it is impossible for mold to grow on AAC.


11. We encourage building the entire structure with AAC components: the exterior walls, floors, interior walls and roof.  The obvious advantage of this is that all the structure is completely compatible, but of equal value is that the entire structure has the same highly energy efficient thermal mass, but also because of its high sound isolation value it makes for a very quiet house.


12. The ideal finish for AAC walls interior and exterior is light weight stucco which adds to its thermal value, but also aesthetically.  There is no need for sheetrock with its hugely joints and screw pops.  All the walls have a smooth solid finish.  Many of the light weight stuccoes have color integration so that the walls even if dinged will not expose the surfaces below.