Concrete blocks: cured and aged before they go into a wall
Applies only if your house has concrete block walls.
Why — act while you have leverage
A concrete block still shrinking is a block that will crack the wall it is in. Blocks laid too young are one of the commonest causes of the fine vertical cracks that appear over the first year.
What to look at
- Batch date from the manufacturer, not just a delivery date
- Blocks dry when laid
- A block that does not leave cement dust on the hand
How to check it yourself
Blocks are cured by the manufacturer and then allowed to dry before laying — unlike clay, they are NOT soaked before use, because wetting a concrete block makes it swell and it then shrinks in the wall. Ask the age of the batch. Wet the wall face lightly for mortar bond if needed, not the block itself.
Where this comes from: IS 2185 (Part 1) — Concrete masonry units, hollow and solid concrete blocks (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
- AAC blocks: thin-bed mortar, and never soaked
- Fly ash bricks: to the standard, and the right mortar for them
- 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