Fly ash bricks are made to IS 12894, but quality still varies from one maker to another — mostly because of the mix and how long the bricks are cured. These checks take a few minutes and need nothing more than a bucket of water.
The six checks
| Check | How to do it | What good looks like |
|---|---|---|
| Size | Line up several bricks and measure | Consistent length, width and height |
| Edges & faces | Look along the edges and faces | Sharp edges, flat faces, no cracks |
| Sound | Strike two bricks together | A clear ringing sound, not a dull thud |
| Drop test | Drop from about 1 m onto hard ground | Should not break into pieces |
| Water absorption | Weigh dry, soak 24 hours, weigh again | Weight gain within the IS 12894 limit (about 20% or less) |
| Efflorescence | Stand in shallow water, let it dry | Little or no white deposit on the surface |
Ask for this on paper
- The IS 12894 test report for the batch — compressive strength and water absorption.
- The strength class the bricks are sold as.
- How many days the bricks were cured before dispatch.
Warning signs
- Bricks that crumble at the corners when handled.
- Large variation in size within the same load.
- Heavy white patches after wetting and drying.
- Bricks that feel unusually light or powdery — often a sign of too little cement or poor curing.
Visit before a large order
For a big project, see the bricks before you order. You are welcome at our plant at Thirumalayampalayam, Coimbatore — call ahead and we will show you the stock and test reports.