About AAC Block

Dr Johan Axel Erikkson, along with Professor Henrik Kreuger, developed AAC blocks in the early 1920’s, and followed it up with patenting the manufacturing process in 1924. By the year 1929, AAC blocks were produced in full swing in Sweden. Today, AAC blocks are widely manufactured as a construction material across our country in states like Maharashtra, Tamil Nadu, Gujarat, Uttar Pradesh, Andhra Pradesh, Karnataka, Odisha, West Bengal, Rajasthan & several other states. The popularity of AAC blocks is steadily growing in north eastern states of India, owing to increasing demand for housing units and commercial spaces. However, the market for this construction material is still in its infant stage in the north-eastern parts of India.

What are AAC Blocks?
AAC blocks are precast, foam concrete, sustainable construction material made from aggregates of sand, calcined gypsum, fly ash, lime, Ordinary Portland cement, water and aluminum powder. After mixing and moulding, the concrete is autoclaved under heat and pressure and it thus gains its distinctive properties. AAC bricks are in high demand, owing to its properties like light weight, thermal insulation, sound insulation, ease of work, fire resistance, etc.

Where are AAC Blocks used?
AAC blocks are widely used in the construction of apartments and other types of residential properties, commercial buildings, such as hotels, offices, hospitals and schools. Owing to their excellent heat insulation capacity, AAC blocks find application in interior and exterior construction. They are ideal for high-rise structures.

Why use AAC block

AAC blocks have a wide range of advantages and their usage truly benefits the construction. With AAC Blocks, you can get better Thermal Insulation which keeps the spaces comfortable and leads to Energy Saving. It improves the Acoustic Performance in the building and offers Moisture Resistance and Fire Resistance. AAC blocks have a better Workability and are Easy to Install that leads to Fast Construction. These blocks have High Strength which makes it Earthquake Resistant and gives it more Endurance. AAC blocks are Lightweight compared to clay bricks and hence offer more Precision. It has a good Water Barrier and reduces plaster cost which leads to overall cost saving in the construction.

AAC Block Advantages


Ultralyte AAC blocks are 1/3 of weight of the red clay bricks which makes them easy to transport, thus saving on the overall logistics and shipping costs, as compared to the costs involved in the transportation of traditional red clay bricks.


With its superior strength, Ultralyte AAC blocks give durability to the finished structure which makes them more capable of handling higher seismic loads, compared to structures with conventional bricks.


Ultralyte AAC Blocks are larger than traditional bricks, which leads to easy installation and gives the desired flexibility for making adjustments by cutting, shaping etc. These blocks have fewer joints and consistent dimensions, which makes laying them easier and makes the construction process faster.


The average compressive strength of the Ultralyte AAC Block is 3 to 5 N/mm2. Thus, it is much stronger and better than bricks of the same density.


Owing to the unique cellular, bee-hive like structure, the fire resistance quotient of ultralyte AAC Blocks is very high.


Ultralyte AAC blocks are prepared from inorganic materials, which help in protecting the structure from pests such as termites, rodents, etc.


The lightweight and porous structure of Ultralyte AAC blocks enables high sound reduction which makes it a perfect fit for the construction of studios, hotels, and hospitals.


The macro-pores inside Ultralyte AAC blocks ensure low absorption of water, thus providing better moisture protection to the walls & structure.


The material in Ultralyte AAC Block contains small air pockets and hydrogen is used to foam the concrete, thus giving it an excellent heat insulation property that allows temperatures to be warm in winters and cool in summers. Therefore, it can significantly lower your air-conditioning & heating costs by about 25%.


Ultralyte AAC blocks are made from natural and non-toxic raw materials and their manufacturing process generates minimum waste. Some of the waste or off cuts generated can be recycled or used in aggregates. As it is made from non-biodegradable materials, it makes the building durable and stable, preventing rot or mould. Furthermore, being lightweight, energy-efficient and easy to install, AAC blocks also minimize labour costs.

Easy Workability

 AAC Blocks are lightweight and thus easy to move. This results in easier workability with these blocks during construction.

Cost Saving

AAC blocks prove to be a cost-efficient building material in the construction industry, making the process rapid and efficient. They are cost-saving construction and building material that help in reducing labor and transportation time. Compared to conventional red brick, AAC blocks weigh 80% less. There is a reduction of deadweight that results in the removal of cement and steel.

Fast Construction

Ultralyte AAC Blocks reduces construction time by 20% different sizes of blocks helps reducing the number of joints in wall masonry, lighter blocks facilitate more comfortable and faster construction. These blocks are easy to install also sets and hardens quickly.

Reduce Plaster Cost

 AAC Blocks have great strength and durability and the cover an area quickly, which leads to reduction in plaster related costs. 


With its high durability, earthquake & fire resistance, AAC Blocks bring a high level of endurance in any construction.


AAC Blocks are cut in precise sizes and shapes that help in the overall precision in the construction.

Non Toxic

Ultralyte AAC Blocks are environment friendly and thus are a non toxic building material for your construction.

Ultralyte AAC Block VS Burnt Clay Brick

Size 600 mm x 200 mm x 75-300 mm 225 mm x 100 mm x 65 mm / 230 mm x 75 mm x 115 mm Clay bricks need more mortar since the size is smaller. But mortar requirement is lesser in Ultralyte AAC blocks due to its bigger size
Precision in Size 1.5 mm (+/-) 5 to 10 mm (+/-) The Ultralyte AAC block is dimensionally more accurate as it is produced with advanced wire cut technology in a factory.
Compressive Strength 3-5 N/mm2 (IS 2185, Part-3) 3.5-7 N/mm2 Using Ultralyte AAC blocks reduces the load on the foundation and other structural components in a structure due to its lower self-weight.
Density 550-650 kg/m3(oven dry) 1800-2000 kg/ m3 Ultralyte AAC blocks have air voids and hence have better fire resisting property compared to red clay bricks.
Fire Resistance 2 to 7 hours depending upon thickness Around 2 hours Ultralyte AAC blocks are resistant to thermal variations. It reduces operation and maintenance cost drastically.
Energy Saving Lesser electricity consumption for air conditioner or heating load Higher electricity consumption for air conditioner or heating load Ultralyte AAC block with very low thermal conductivity keeps the interior cool in summer and warm in winter.
Thermal Conductivity K value = 0.16 W/mk K value = 0.81 W/mk The Ultralyte AAC block has better sound insulation properties, due to its air voids. Therefore it is an ideal material for wall construction in hotels, auditoriums, studios, hospitals etc.
Noise Transmission / Sound Insulation 45-45db for 200mm thick wall More than 50db for 230mm thick wall The Ultralyte AAC block has better sound insulation properties, due to its air voids. Therefore it is an ideal material for wall construction in hotels, auditoriums, studios, hospitals etc.
Mortar consumption per M3 with 1:6 0.5 bag of cement 1.40 bag of cement Ultralyte AAC blocks are bigger than conventional bricks. Bigger size means less number of joints. Less joints result in reduction of mortar usage.
Savings in Plaster Big savings in quantity & the cost of plastering No savings in quantity & the cost of plastering Unlike red clay bricks, Ultralyte AAC blocks have uniform shape and texture which give an even surface to the walls thus reducing the overall cost and quantity of plaster.
Water Usage Low, needs only surface wetting before use High, needs curing before and after use Ultralyte AAC blocks save water consumption
Speed of construction Very high Comparatively lower The productivity of the mason (with Ultralyte AAC blocks) increases up to 3 times, due to its bigger size & less number of joints.
Environmental Impact No fertile top soil consumed Huge amount of fertile top soil consumed Ultralyte AAC block is 100% environment friendly & is a walling material of choice in IGBC and GRIHA certified buildings.
Moisture/ Water Resistance Very Good (no continuous pores and capillaries) Average (suction through continuous capillary action) Ultralyte AAC blocks do not have any ‘micro-pores’ of continuous ‘capillaries’ through which exterior surface water can be absorbed into the interiors. Hence it leads to long life of paint and healthy interiors.
Quality / Durability Uniform and finished Varies with each piece Ultralyte AAC blocks with are produced in a factory with automated processes, so, they have uniform quality and are more durable.
Earthquake Resistance Good. Generally, they have conformance to requirement of seismic zone IV & V Average. Conditional Conformance to seismic zones IV & V Earthquake forces on structure are proportional to the weight of the building. Hence Ultralyte AAC blocks show excellent resistance to earthquake forces.They absorb and transmit less seismic forces in the event of any earthquake.The structure has millions of tiny cells which cushion the buildings from major force, preventing progressive collapse.
Maintainence Comparatively Lesser due to its superior properties High Ultralyte AAC block reduces operating cost substantially due to its energy saving & nil efflorescence property by 30% to 40%.
Wastage Due to Breakages Minimal (1-5%) Approximate 10 to 15% If any breakage happens in the Ultralyte AAC blocks, it would be into two or three pieces which can be utilized in masonry as “brick bat”
Pest & Termite Resistance High Low AAC Blocks do not allow spread of termites and growth of pests and hence provides longer life to expensive wooden interiors.
Fume Resistance Good Average AAC Blocks are completely inorganic and hence do not generate any toxic fumes or poisonous gases harmful to the occupants.

Ultralyte AAC Block Cost Advantages

Using Ultralyte AAC Blocks is a great way to save a lot on your construction costs. There are many reasons for this. AAC blocks are lightweight and hence much cheaper to transport. These blocks don’t require as much curing or mortar and labour. Using AAC Blocks, you can build walls with lesser number of joints which brings down the cost as well. And due to all of the above, the construction time is drastically reduced as well, which further reduces the overall cost of construction.

AAC Block Manufacturing Process

When AAC is mixed and cast in forms, several chemical reactions take place that give AAC its light weight and thermal properties. Aluminium powder reacts with calcium hydroxide and water to form hydrogen. The hydrogen gas foams and doubles the volume of the raw mix creating gas bubbles up to 3mm in diameter. At the end of the foaming process, the hydrogen escapes into the atmosphere and is replaced by air. This process requires 30% less energy compared to clay brick manufacturing. When the forms are removed from the material, it is solid but still soft. It is then cut into either blocks or panels, and placed in an autoclave chamber for 12 hours. Because of the relatively low temperature used AAC blocks are not considered fired brick but a lightweight concrete masonry unit. After the autoclaving process, the material is ready for immediate use on the construction site.