Fly ash bricks: to the standard, and the right mortar for them
Applies only if your house has fly ash brick walls.
Why — act while you have leverage
Fly ash bricks are more consistent in size than clay and are widely sold on price alone. Quality varies enormously between yards, and the cheap ones fail on strength rather than on looks.
What to look at
- A certificate against IS 12894 for the batch delivered
- Consistent size across the stack, which is the main reason to choose them
- Joints scraped out for plaster key before the wall dries
- Fly ash brick test certificate against IS 12894
Documents to ask for
- Fly ash brick test certificate against IS 12894
How to check it yourself
Ask for the manufacturer's test certificate against IS 12894 for compressive strength and water absorption. These bricks need only light wetting, not the long soak clay takes. Their smoother faces mean plaster needs something to grip — raking joints matters more here than with clay.
Where this comes from: IS 12894 — Pulverized fuel ash-lime bricks (indian standard or building code)
More masonry and wall checks
- Photograph before this is covered
- Bricks or blocks soaked before laying, and joints filled
- Masonry cured, and lintels bear the specified length
- Laterite blocks: soaked properly, and laid with the right mortar
- Burnt clay bricks: water absorption within the standard
- Concrete blocks: cured and aged before they go into a wall
- AAC blocks: thin-bed mortar, and never soaked
- Mortar measured by gauge box, not by shovel
- Sand bulking allowed for before the mix is batched
- Mortar used within its working time, and never re-tempered