Building a new home incurs many monetary and environmental costs. One of the biggest sources of these costs is the material used in the masonry blocks, also known as the literal building blocks of your home.
Concrete is a very popular masonry material and one of the most widely used synthetic materials on Earth. Its popularity no doubt stems from the fact that it is incredibly durable and structurally sound.
However, manufacturing concrete produces a large carbon footprint – an estimated 5% to 7% of carbon dioxide emissions.
But what if you want a building material that matches structural strength with environmental sustainability? Consider using aircrete, a cheap, lightweight alternative to traditional concrete that offers many of the same benefits.
When building a new home, it’s hard to beat affordability and sustainability. But those are not the only benefits aircrete can offer. Keep reading to learn why you should consider using aircrete in your next building project.
What Is Aircrete?
Aircrete is a building material often used in the form of masonry blocks. Builders increasingly regard aircrete, also known as Autoclaved Aerated Concrete (AAC), as an eco-alternative to traditional concrete building blocks.
Durable yet lightweight, this precast building material offers sufficient compressive strength for non-load-bearing walls while protecting against various climate elements.
Aircrete is essentially a mix of water, foaming agent, and cement. The foaming agent creates tiny air bubbles that, when evenly dispersed, provide many benefits (outlined in the next section).
The target amount of foaming agent depends on the intended application for the aircrete. As a rule of thumb, aircrete with more air bubbles offers greater insulation capacity but less compression strength.
Blending traditional concrete relies on a coarse aggregate such as gravel. This composition creates a denser material with greater compressive strength. However, it lacks many of aircrete’s most attractive properties – particularly regarding insulation.
For increased structural strength, builders might mix traditional aggregate into aircrete.
Premade aircrete blocks will make variations to this basic recipe. For example, manufacturers such as H+H Aircrete use a mixture of cement, lime, pulverized fuel ash, and aluminum powder.
Whatever the foaming agent, these uniformly distributed stable air cells are crucial to the performance of aircrete. For this reason, you might also hear aircrete referred to as aerated concrete, foam concrete, lightweight concrete, or cellular concrete.
Benefits of Using Aircrete
We’ll discuss aircrete’s sustainability properties in a later section. But, first, let’s look at the tangible benefits aircrete can lend to your building structure.
Cheaper Associated Costs
Many builders tout aircrete as a low-cost option thanks to the relative cheapness of the materials used to make aircrete: water, foam, and cement.
As with any construction project, the exact cost of building with aircrete varies depending on several factors, particularly if you’re mixing aircrete yourself. Generally speaking, however, building with aircrete is less expensive than building with traditional concrete.
Hajjar Gibran, the founder of DomeGaia — a company that builds quirky dome-shaped houses using aircrete, believes aircrete has potential as a building material for affordable housing.
Gibran estimates DomeGaia’s aircrete costs $1 to $2 per square foot and inch of thickness. By this calculation, using aircrete to build a 1,000-square-foot building with 4-inch thick walls would cost under $8,000.
Even if you’re not interested in living in a dome home, aircrete will probably be a cheaper building material than traditional concrete. And it is definitely more environmentally sound than timber.
One of the most significant advantages aircrete offers over traditional concrete is its insulation abilities.
The moment you step inside an unsealed concrete basement, you will feel the room’s chilly dampness. Some traditional concrete blocks increase their insulation capacity by adding rigid insulation such as polystyrene foam blocks.
Aircrete blocks don’t require this addition. The foam or air bubbles dispersed throughout the aircrete naturally provide insulation properties. Aircrete is also very air-tight, allowing for much better heat consistency than permeable concrete blocks.
Thermal mass is another key to aircrete’s insulation success. (Thermal mass refers to a material’s ability to absorb and retain energy from heat.)
High-density materials such as traditional concrete blocks have high thermal mass and require a lot of energy to change temperature. Timber and other lightweight materials change temperature quickly because they have low thermal mass.
The thermal mass of aircrete blocks lands between these two extremes, leading to more consistent absorption and distribution of heat within a building.
By some estimations, aircrete could provide an insulation value of R-6 per inch. For comparison, popular insulation material loose fill cellulose offers up to R-3.8 per inch.
Taken at face value, if aircrete offers an R-value of 6 per inch, a house in warm climates could easily meet the recommended R-30 with 5-inch thick walls.
Builders might consider using a thicker application of aircrete in areas requiring additional insulation such as attics, ceilings, or foundations in some cases.
Ease of Application
Several qualities make aircrete easier to use than traditional concrete.
Thanks to evenly dispersed air cells, aircrete has a lower density than concrete. So, in layman’s terms: aircrete is more lightweight, offering easier application and faster home construction.
Additionally, unlike concrete blocks, aircrete blocks can be cut with a handsaw and manipulated with other wood-working tools. Whether you need to carve, drill, or penetrate the material, this quality offers flexibility in construction.
You can easily form aircrete into blocks or pour the liquid form into walls. Aircrete hardens over time, allowing you to shape the material before it has dried. When aircrete does dry, usually over one night, it self-levels.
Aircrete’s flexibility and lower associated production costs make it an attractive material for DIY home builders.
Housing constructions made from lumber pose increased fire risks. However, aircrete outperforms even concrete in terms of its fire-resistant qualities.
The materials used to make aircrete – water, foam, and cement – aren’t typically known for catching on fire; this means that aircrete, like concrete, won’t catch fire even when exposed to extremely hot flames. Aircrete’s fire-resistant quality also results from its porous nature and material makeup.
This quality makes aircrete a great material for building in areas increasingly at risk of wildfires.
In the event of a house fire, aircrete walls will offer superior protection, so consider placing valuable assets in areas walled using aircrete.
The foam or air bubbles within aircrete blocks protect the structure against moisture accumulation. Thanks to reduced moisture accumulation, aircrete will not rot or deteriorate when exposed to water — even in cases of humidity.
Moisture resistance is crucial to preventing mold, decreased air quality, or structural damage caused by dampness.
Use aircrete’s water resistance to your advantage. Identify cold spots in your building project. Apply aircrete in these areas to prevent future risks of moisture accumulation. Whether your building suffers from water accumulation or snow, aircrete will help the structure resist water damage.
At best, pests are a creepy-crawly nuisance. At worst, they can cause severe structural damage. Building with aircrete is a great way to reduce the risk of this nuisance and damage.
Termites are common household pests that frequently attack timber structures. Building your house using aircrete rather than timber makes the risk of termites impossible and irrelevant.
Working with aircrete allows builders to seal openings and enclosures tightly, making it much harder for pests to infiltrate a building’s interior space.
As with many insulation applications, aircrete provides soundproofing, its many air pores reducing the transfer of sound from room to room.
Building with aircrete is a great way to improve a room’s acoustic properties. This soundproofing doesn’t just benefit intrepid drummers who don’t want to disturb their neighbors.
It can also block out unwanted noises that might come from outside your house, such as traffic or barking dogs.
If you calculate the sum of these benefits, you will probably realize that the benefits of aircrete amount to increased sustainability, especially when compared to concrete.
Creating aircrete uses less cement, water, electricity, and heat than concrete production. Plus, the composition of aircrete relies on all-organic materials: cement, water, and air bubbles (or foam).
By some estimates, the right foaming agent can increase the volume of aircrete sixfold. It also produces fewer off-gas emissions than its cement counterpart.
Additionally, the superior insulation properties of aircrete reduce the energy required to regulate a building’s temperature.
Aircrete’s fire, moisture, and pest resistance properties result in a building that requires lower maintenance and is less likely to break down over time, particularly when compared to timber constructions.
Aircrete is durable. Plus, in cases where aircrete does not withstand the tests of time, it’s easy to recycle aircrete. In some cases, you can even reuse aircrete for structural purposes. (It doesn’t even produce damaging emissions over time.)
Disadvantages of Using Aircrete
Maybe you’re thinking aircrete sounds too good to be true. It offers many benefits, but what about the downsides?
When you compare aircrete to traditional concrete, aircrete falls short in two key ways: strength and durability.
Aircrete is not as strong as traditional concrete. Consider using it for internal support rather than foundational structures. Aircrete is better suited to absorbing shock than to bearing loads.
If aircrete is composed too densely of foam, it can lose durability and become brittle. This brittleness won’t necessarily cause structural issues but might lead to chipping and cracking.
The measures of components and methods used to mix aircrete will impact the degree of these shortcomings.
Remember that you can incorporate aircrete and traditional concrete into your building’s structure. First, consider using concrete blocks for load-bearing constructions requiring higher compressive strength levels. Then, use aircrete blocks for interior constructions that require better insulation.
Possible Uses for Aircrete
Builders first developed aircrete to replace breeze blocks. Aircrete blocks are still primarily used for this purpose, placed on internal skins of cavity walls to provide optimal insulation.
However, contemporary builders are starting to use aircrete for many other purposes. For example, some builders, such as the folks at DomeGaia, are using solid aircrete to build not just external skins but entire buildings.
If you’re looking for an eco-friendly alternative to concrete, here are some different household applicationswhere you can use aircrete:
Countertops & Table Tops
Aircrete slabs can provide a lightweight, easy-to-transport alternative to heavy precast concrete slabs.
Building a dog house using aircrete can provide added insulation and bug resistance for your furry friend.
Greenhouse & Shed
Since aircrete offers excellent insulation properties, using this material to build a greenhouse or shed will help keep delicate seedlings toasty and your tools dry.
Garden Beds, Planters, & Retaining Walls
When composed of all-natural materials, aircrete garden beds won’t leach chemicals into your raised soil mounds, unlike treated wood or concrete.
Aircrete is easy to shape during its application, making it an ideal material to form into a dome to house tasty pies.
Completely fire-resistant and easy to use, aircrete is a suitable material for building a rocket stove.
Roof and Roof Panels
Thanks to evenly dispersed air bubbles, using aircrete for poured roofs increases attic insulation capacity.
In cold areas, it’s possible to use aircrete to provide an additional layer of defense against freezing.
Pro Tip: Aircrete might not be the best material for applications that require load-bearing strength (driveways, garage floors, patios). Also, as aircrete is not 100% watertight, it is not a good material to use when building a pool.
You can purchase aircrete masonry in various blocks and panels directly from manufacturers such as Aercon AAC or Hebel. It is also possible to make an aircrete mixture at home.
Airing on the Side of Caution
If you’re purchasing pre-manufactured aircrete, be aware that some manufacturers use foam products containing harmful chemicals. However, it is entirely possible to make aircrete with non-toxic natural resources. In these cases, aircrete blocks are much safer than many other building materials and will not release toxic fumes.
Whether you’re building a new home or making improvements to an existing building, structural safety is the most important thing to consider. When in doubt, hire a professional builder to assess the load-bearing requirements of your building project.
Is Aircrete load bearing?
As we mentioned in the article. Aircrete can handle some weight, but for projects that require high-compressive strength, you’re better off with concrete.
What is the fire resistance of aircrete?
See our above section in this article, “The materials used to make aircrete – water, foam, and cement – aren’t typically known for catching on fire; this means that aircrete, like concrete, won’t catch fire even when exposed to extremely hot flames.
Aircrete’s fire-resistant quality also results from its porous nature and material makeup.
This quality makes aircrete a great material for building in areas increasingly at risk of wildfires.”
Who came up with aircrete?
Mr. Willem van Boggelen invented aircrete around fifty years ago. Here was a mechanical engineer and also was involved with Fluid Mechanics. He also founded Aircrete Europe back in 2002.
CEMENT AND CONCRETE: THE ENVIRONMENTAL IMPACT: Link
Building an aircrete dome home – PDF
ADVANTAGES AND IMPLICATIONS OF LOW DENSITY AIRCRETE PRODUCTS FOR THE CONSTRUCTION INDUSTRY – PDF
This article was produced by Nature of Home, and syndicated by healing-water.org.