Bricks vs fly ash bricks: which one should you actually buy?
Comparing bricks per piece is the most common mistake in walling procurement. The number that matters is the installed cost per square metre of finished wall.
Last updated: 12 July 2026 · 6 min read
Strength and absorption
A good first class clay brick gives around 7.5 N/mm² compressive strength with up to 20% water absorption. A good fly ash brick reaches 7.5–10 N/mm² with noticeably lower absorption.
Both figures vary enormously by producer. Ask for a test report rather than trusting the category.
Dimensional accuracy changes the maths
Fly ash bricks are pressed in a mould, so they come out consistent. Clay bricks are fired in a kiln and vary. That difference shows up as mortar thickness and plaster thickness.
On a typical wall, the smoother, truer face of a fly ash brick can cut plaster thickness by several millimetres — which across a whole house is a meaningful saving in cement and sand.
Where clay bricks still win
Local masons often know clay bricks better and lay them faster. In regions with good kiln clay, first class bricks can be both cheaper and stronger than the available fly ash product. And for exposed brickwork, nothing matches the look.
The environmental angle
Clay brick production consumes topsoil and burns coal. Fly ash bricks use thermal plant waste and cure rather than fire. Several states now mandate fly ash products within a defined radius of power plants — worth checking before you commit to a kiln order.
The takeaway
Run the numbers per square metre of finished wall including mortar and plaster. In most Chhattisgarh markets, fly ash bricks win that comparison.
Compare live supplier rates or read the material category guides.