General

What is Autoclaved Aerated Concrete Designs(AAC)? Autoclaved aerated concrete designs is made with completely inorganic, sustainable materials and there is no waste byproduct in its production. Unlike conventional formed concrete blocks (CMU) which is made with cement and course fine aggregate it is made with sand, lime a special kind of white clay and cement. It is mixed with water in large square forms and aluminum oxide is added to the slurry and this causes a chemical reaction to occur. This reaction causes thousands of tiny hydrogen bubbles to rise in the mix and the slurry rises like yeast in bread dough. The result is millions of tiny air pockets are trapped in the concrete as it begins to cure. It is then placed in autoclaves to provide heat and pressure to cure it to its intended compression strength. Though it requires a certain amount of energy in this process it is still less than half the energy that is consumed in the production of bricks and concrete blocks or even in kiln drying wood. When it is completely cured it is wire cut into dimensionally accurate blocks unlike CMU blocks which are not dimensional accurate and thus require being put together with thick bed mortar which can deteriorate and weaken the structure. All the shavings from cutting the block are captured and used to make thinnest mortar for putting the blocks together and to also make lightweight stucco which is an ideal finish for the exterior or a lightweight plaster for the interior walls. In this process it is completely sustainable with no waste by-products since everything is recycled. I became very fascinated with this product and yet skeptical as usual, and so I continued to research the product looking for performance reports. I read about a chemical factory in Germany made of Autoclaved Aerated Concrete Designs, which had a fire, and the fire was so intense the firefighters had to stand back and watch it burn for 4 days straight. It was assumed that the exterior structure made of AAC was compromised so engineers checked it out and took core samples and it was as sound as the day it was completed even though the steel internal structure was vaporized. In 8 weeks, the factory was back in business. I have seen what happens to CMU block structures when exposed to such intense heat. It just crumbles under this kind of stress. I found another article and saw pictures of a house that survived a wildfire. The picture showed hundreds of slabs and basements all around except for this one house made of Autoclaved Aerated Concrete Designs and had a clay tile roof was the only thing still standing. I also found an article and pictures of two Autoclaved Aerated Concrete Designs houses that were the only structures still standing after massive flood had swept all the other structures away. Later I read about an Autoclaved Aerated Concrete Designs house in Indonesia that survived a class 4 cyclone. The pictured showed a vast expanse of vacant slabs and rubble and this one house standing unscathed. It had not only survived the high winds, but also the storm surge of water. It is often the case that a house may survive the high winds of a hurricane/cyclone and even the objects that fly around and hit the structure during the storm, but when the seas recede, they finish off the houses already impacted. This Autoclaved Aerated Concrete Designs house had survived all these harsh elements that had destroyed all the other neighboring homes. I was truly impressed and began to wonder if this material was available in the United States. I had read that one of the manufacturers, Hebel had plans for production of their Autoclaved Aerated Concrete Designs blocks in America and that they already had a factory in Monterey, Mexico and shipped their products worldwide. I decided to make a call to Hebel in Germany to learn as much as I could. I learned they were building a manufacturing plant in Adel, Georgia, which is about a 4 ½ hour trip from Atlanta. I asked for all the literature they have on their products and asked the engineer who I was speaking to me to let me know when they would start production in Adel. I learned all I could about building with Autoclaved Aerated Concrete Designs and decided I would design and build a house for my own family using this product. Twelve weeks later I got a call from the German engineer whom I had spoken with earlier. He told me that he was in Adel, Georgia and they were starting production of their blocks. I made an appointment to meet him down there. In the meantime, I came up with at least a hundred questions I jotted down that I wanted to ask while I was there. I took my house plans down with me and spent 2 ½ days there. I got a tour of the plant and watched a slurry being made and the chemical reaction when they introduced the aluminum to the mix. It was a marvel to behold, seeing the batch rise. They had a two-day class for me to attend, which included building a small room with Hebel blocks and mortar.  This was a great hands-on experience, seeing how easy it was putting the blocks together and sawing the block with a basic hand saw. I spent at least half a day going over my building plans and learning what alterations I needed to make and the reinforcement necessary to make this house a strong solid monolithic structure. I got a certification as a Hebel approved builder. I was convinced enough to make the investment of my time and financial resources to build my first AAC house for my own home for my family. I had known even before I had finished my research that I would be building a house different and superior to conventional stick framed

I have had inquiries about Insulated Concrete Form (ICF) construction. What is ICF? Should I consider ICF house plans for my new home? Those who have read my profile know that for more than 20 years I have designed and built using solid construction systems. I did so because I believe solid construction methodology is superior in every way to conventional composition construction as in framed construction. It is important when planning to design and build a house for your next home to take into consideration that when you clear a lot and build a structure you permanently change the ecosystem that was there. Pinpoint your home’s ideal location on the property. Assess which trees to preserve and plan how to repurpose any timber you must clear. This strategic approach ensures optimal site utilization and minimizes ecological impact. Next, instead of just orienting your house to the street, consider orienting your house to the sun to take advantage of passive or active solar energy to heat and cool your home. Survey your site for materials that complement your habitat. Look for stone or timber you can incorporate. Blend these elements seamlessly into your design. Consider how each resource enhances your plan. Integrate local materials to create a harmonious living space. Is there water on your site? Is your lot large enough to use convection ground tubes or bore wells for geothermal heating and cooling?  These are just a few of the things you should peruse when finalizing and implementing a plan for the construction of your next home. My point is your primary concern should be to reduce as much as possible your impact on the environment. Now this brings me back to solid construction and the use of Insulated Concrete forms (ICF). Most of my experience has been in specializing in using a hybrid approach to designing and building a solid concrete house. I recommend using ICF as the best system for construction below ground level either in a basement or in an earth bermed house. For above grade I prefer using Autoclaved Aerated Concrete (AAC), which I will address in a future blog. There are at least a dozen companies which have their own patented insulated forms. What is common to all of them is they make a permanent concrete form using polystyrene foam for the shell of the building blocks for the forms or as in the case of Rastra Forms they make a cement form blocks in which use polystyrene beads as an aggregate and insulating element. Most of the companies use 2 inches or more of 2-pound density foam on the inside and outside walls of their form blocks. 2 lb. density polystyrene foam has a resistance to heat transfer from inside or outside with a rating of R-6 per inch so a standard 12” form has a rating of R-24 and the solid 8 inches of concrete on the inside has a thermal mass that is hard to calculate but is at least R-2. Save Green by Building Green These thick, airtight walls act like a warm hug for your home. Cozying you up while fending off sky-high utility bills. In fact, studies show ICF homeowners can slash energy costs by over 50%! But that’s just the start. These sustainable stunners will keep your wallet and Mother Nature happy for decades. Boasting fireproof forms, steel-reinforced durability, and low (like, hardly any) maintenance needs. Fortresses for the Modern Age Worried about wild weather? Scoff at severe storms when you live in an ICF stronghold! With their beastly steel-reinforced concrete cores, these homes shrug off raging winds and angry skies. They’ll keep your family safe and serene, no matter what’s happening outside. And that solid construction isn’t just brawn, it’s function too. With superior noise insulation, ICF houses hush the chaos of the outside world. More Than Meets the Eye (And Budget!) Okay, we know what you’re thinking: “This all sounds amazing, but what about the price!” True, ICF houses can have higher upfront costs. But stick with us for a second! Over the lifetime of your home, those energy savings, low maintenance, and storm-defying strength, house resell value, more than make up for it. We’re talking decades of cost-effective comfort! Plus, with free ICF house plans and concrete house plans available online for every dream home—from snug cottages to sprawling estates—you can easily find an affordable fit. ICF House Plans Advantages Insulation When you consider that a standard wood framed wall is R-13 using conventional fiberglass insulation between wood 2×4’s the difference is remarkable in energy consumption over the lifetime of your habitation. Another factor to understand is that fiberglass insulation ratings are primarily based on heat transfer from the inside of the house to the outside, but not so much from the outside in. Solid foam insulation is superior in this respect because it is unbiased in that it is as effective in resisting heat induction from the outside and this can be very important especially in hotter climates in reducing cooling loads.  Solid foam insulation is also at least twice as effective in sound isolation than fiberglass insulation. Sound Isolation Another advantage of solid insulation as in the use of ICF construction is its high sound isolation over conventional construction and insulation.  Such solid construction makes for a quiet home, whether from the sound pollution from outside or the hum of mechanical systems. Rebar Another common aspect of ICF systems is that they all use an integrated way of placing rebar reinforcement in proper spacing both vertically and horizontally. This is critical to this form of construction. Block Patterns What distinguishes these different companies’ forms is primarily in how the blocks fit together, such as in a tongue and groove pattern or a waffle pattern. Wall Attachments The other factor is the method they provide for attachments to the forms such as sheetrock, furring strips or paneling. Wall Strength Concrete volume affects form strength and thermal properties. More concrete often yields sturdier