7 min read · Structural materials

Bricks & blocks — red clay, fly ash, AAC and CLC compared

The choice of brick or block affects your building's thermal comfort, structural performance, construction speed and long-term maintenance. Here is a complete comparison.

Simple summary — for homeowners

For most homes in Bengaluru, AAC (Autoclaved Aerated Concrete) blocks are the best choice for partition walls — they are lighter, faster to build with, and provide better thermal insulation than traditional red bricks. Red clay bricks are still excellent for load-bearing walls. Fly ash bricks are a sustainable and cost-effective alternative to red clay. Avoid cheap hollow concrete blocks for internal walls — they offer poor insulation and are difficult to cut for electrical and plumbing work.

Complete comparison

Costs are per unit and vary by region, quantity and supplier.

Type
Weight
Strength
Thermal
Cost
Best use
Red clay brick
3.5–4 kg
3.5–7 MPa
Good
₹7–12/brick
General masonry, load-bearing walls
Fly ash brick
3–3.5 kg
7.5–10 MPa
Good
₹6–10/brick
Non-load-bearing, partition walls
AAC block
7–8 kg/block
3–5 MPa
Excellent
₹45–65/block
Non-load-bearing, thermal insulation
CLC block
9–11 kg/block
3–6 MPa
Very good
₹38–55/block
Non-load-bearing, soundproofing
Hollow concrete block
17–18 kg
5–7 MPa
Average
₹35–50/block
Compound walls, boundary walls
Solid concrete block
28–30 kg
7–10 MPa
Poor
₹50–70/block
Load-bearing, retaining walls

Red clay brick vs AAC block

Red clay brick
Traditional — proven over centuries
Good compressive strength for load-bearing
Heavy — increases structural load
Higher plastering cost — uneven surface
Absorbs water — needs good waterproofing
Slower construction — smaller unit size
AAC block
3× lighter than clay brick — reduces structural load
Excellent thermal insulation — cooler interiors
Faster construction — larger unit size
Better dimensional accuracy — less plaster needed
Fire resistant — up to 6 hours
Higher material cost but lower overall wall cost

Quality checks on site

01
Water absorption test
A good brick should absorb less than 20% of its weight in water after 24 hours of immersion. Soak a brick and weigh before and after. Excessive absorption leads to efflorescence and dampness.
02
Drop test
Drop a brick from 1 metre height onto a hard floor. A good quality brick should not break into more than 2 pieces. Crumbling indicates poor firing or manufacturing.
03
Scratch test
A hard nail should not easily scratch the surface of a well-fired brick. Soft, powdery surfaces indicate under-firing.
04
Dimensional consistency
Check 20 bricks at random — they should all be within ±3mm of the standard size. Inconsistent sizing means higher mortar consumption and uneven walls.
05
Check AAC block density
AAC blocks come in densities of 550–650 kg/m³. Higher density means higher strength. Ask for the manufacturer test certificate.
Homekrate recommendation
Basic
Red clay brick or fly ash brick
Cost-effective for load-bearing and partition walls. Good quality from local manufacturers.
Standard
Fly ash brick for load-bearing + AAC block for partitions
Our default combination — structural efficiency with thermal comfort.
Premium
AAC block throughout + fly ash for boundary
Lightest structure, best thermal performance, faster construction.
More guides
Concrete grades →Sand guide →Cement guide →
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