AAC Blocks vs Red Bricks

Choosing the right wall material is one of the most important decisions in any construction project. For decades, traditional red bricks have been widely used. However, in recent years, AAC blocks have become a strong alternative. Both materials have their own strengths and limitations. Therefore, understanding the difference between AAC blocks and red bricks helps builders, engineers, and homeowners make better choices.

In this blog, we will clearly compare AAC blocks and red bricks in simple terms, covering cost, strength, durability, insulation, and suitability for different projects.

What Are AAC Blocks?

AAC blocks, also known as Autoclaved Aerated Concrete blocks, are lightweight building units made from cement, lime, fly ash, sand, water, and aluminium powder. During manufacturing, the aluminium reacts and creates air pockets. As a result, the blocks become light yet strong.

AAC blocks are factory-made under controlled conditions, which ensures uniform quality. Because of their structure, they provide good thermal insulation and reduce the overall dead load of the building.

What Are Red Bricks?

Red bricks are traditional clay bricks manufactured by moulding clay and firing it in kilns at high temperatures. They have been used for centuries in residential and commercial buildings.

Red bricks are known for their strength, durability, and availability. Since most masons are familiar with them, they are still widely used in many parts of India.

Size and Weight Comparison

AAC blocks are much larger in size compared to red bricks. This means fewer blocks are required per square metre of wall. Additionally, AAC blocks are nearly three times lighter than red bricks.

Because of this reduced weight, AAC blocks decrease structural load. Consequently, this allows savings in steel and concrete for foundations and frames.

Strength and Durability

Red bricks have high compressive strength and perform well in load-bearing walls. However, AAC blocks also offer sufficient strength for most modern framed structures.

Although AAC blocks are lightweight, they are durable when used correctly with proper plastering and waterproofing. In framed buildings, AAC blocks perform just as well as bricks.

Thermal and Sound Insulation

One major advantage of AAC blocks is insulation. The air pockets inside AAC blocks reduce heat transfer, keeping buildings cooler in summer and warmer in winter.

On the other hand, red bricks have lower insulation capacity. Therefore, buildings made with bricks may require additional insulation layers to achieve comfort.

AAC blocks also offer better sound insulation compared to bricks, making them suitable for residential apartments and hospitals.

Construction Speed and Labour

Since AAC blocks are larger and lighter, construction is faster. Less mortar is required, and handling becomes easier for workers.

In contrast, using red bricks takes more time due to their smaller size. More joints mean more mortar and longer curing time.

As a result, AAC block construction often reduces overall project duration compared to brick masonry.

Cost Comparison

At first glance, AAC blocks appear more expensive than red bricks. However, when considering savings in mortar, plaster thickness, steel, and construction time, AAC blocks often prove economical.

Red bricks may seem cheaper initially, but higher labour cost and material consumption can increase the final expense.

Environmental Impact

AAC blocks are considered eco-friendly because they use industrial waste like fly ash. Their production consumes less soil compared to bricks.

Red bricks require large amounts of fertile topsoil and high kiln temperatures. Therefore, traditional bricks have a higher environmental impact.

Water Absorption and Plastering

AAC blocks have controlled water absorption. However, they require proper surface preparation before plastering.

Red bricks absorb more water, which can cause dampness if not cured correctly. Thicker plaster is usually needed on brick walls to achieve a smooth finish.

Applications in Construction

AAC blocks are best suited for:

• High-rise buildings
• Residential apartments
• Commercial structures
• Green buildings

Red bricks are commonly used in:

• Independent houses
• Boundary walls
• Load-bearing structures
• Rural construction

AAC Blocks vs Red Bricks 

IS Codes for AAC Blocks and Red Bricks

IS Codes for AAC Blocks

• IS 2185 (Part 3): 1984
  Concrete masonry units – Specification
  This is the main IS code for AAC blocks, covering dimensions, compressive strength, density, and testing methods.

• IS 3495 (Part 1 to 4): 1992
  Tests on burnt clay building bricks
  Some test methods like compressive strength and water absorption are also referred to while comparing AAC blocks with traditional bricks.

• IS 12894: 2002
  Pulverised fuel ash for use as Pozzolana
  Relevant because fly ash is a major raw material used in AAC blocks.

IS Codes for Red Bricks

• IS 1077: 1992
  Common burnt clay building bricks – Specification
  This is the primary IS code for red bricks, defining quality, dimensions, strength, and tolerance limits.

• IS 3495 (Part 1): 1992
  Determination of compressive strength of burnt clay bricks

• IS 3495 (Part 2): 1992
  Determination of water absorption of bricks

• IS 3495 (Part 3): 1992
  Determination of efflorescence of bricks

Supporting IS Codes for Masonry Work

• IS 2212: 1991
  Code of practice for brickwork
  Applicable to both AAC blocks and red bricks during masonry construction.

• IS 2250: 1981
  Code of practice for preparation and use of masonry mortars

Conclusion

Both AAC blocks and red bricks have their own place in construction. While bricks remain a trusted choice for traditional buildings, AAC blocks are ideal for modern, fast, and sustainable construction. The final decision should depend on project type, budget, climate, and structural design.

FAQs on AAC Blocks and Red Bricks

1. Are AAC blocks stronger than red bricks?
AAC blocks are strong enough for framed structures, but red bricks have higher compressive strength for load-bearing walls.

2. Do AAC blocks crack easily?
No, if proper workmanship and curing are followed, AAC blocks perform well without cracking.

3. Which is better for hot climates?
AAC blocks are better due to superior thermal insulation compared to bricks.

4. Can AAC blocks replace red bricks completely?
In modern RCC buildings, AAC blocks can easily replace bricks, but traditional houses may still use bricks.

5. Are AAC blocks suitable for external walls?
Yes, with proper waterproof plaster and finishing, AAC blocks work well for external walls.