A 3 hole brick is a burnt clay brick with three round holes through it. Most are machine-made (extruded and wire-cut), so they have sharper edges and more even sizes than hand-moulded bhatta bricks. In India, perforated clay bricks are covered by IS 2222, and strength classes follow IS 1077.
Common sizes
| Type | Size (mm) | Where you find it |
|---|---|---|
| Non-modular | 230×110×70 or 230×115×75 | Most of North India |
| Modular | 190×90×90 | Government and IS-standard work |
Sizes vary between plants. Measure ten bricks end to end before you calculate quantities.
How they compare with solid bricks
| 3 hole brick | Solid hand-moulded brick | |
|---|---|---|
| Weight | Lighter, by the volume of the holes | Heavier |
| Size and edges | Even size, sharp edges | Varies more between bricks |
| Bond with mortar | If laid holes-up, mortar enters the holes and keys the courses together | Bond is on the bed face only |
| Plaster needed | Thinner, because the wall is truer | Thicker, to cover uneven bricks |
| Mortar used | Slightly more, as some fills the holes | Less |
How much lighter a 3 hole brick is depends on the hole size. If weight matters, for example on an upper floor, weigh a few bricks from the plant rather than relying only on a catalogue figure.
Example: the 3 hole brick we make at BricksStreet
Naresh Sihag, who writes this site, runs BricksStreet, a clay brick maker with its own kiln in Rajasthan. Here is our standard 3 hole wire-cut brick, as an example of what to ask any supplier for:
| Specification | BricksStreet 3 hole wire-cut brick |
|---|---|
| Size | 230 × 114 × 76 mm (9 × 4.5 × 3 inch) |
| Holes | Three, 33–38 mm diameter, through the 114 mm width |
| Size tolerance | ±2 mm (machine wire-cut) |
| Minimum compressive strength | 105 kg/cm² (about 10 N/mm²) |
| Weight | About 10% lighter than a solid brick of the same size |
Because the holes run through the width, this brick is laid with the holes horizontal, so the round pattern shows on the wall face in exposed brickwork. Bricks whose holes run top to bottom are laid holes-up instead. Always follow the maker's instruction for hole direction.
You can see our product range at bricksstreet.in. Whoever you buy from, ask for the same details in writing.
Where to use them
- Infill and partition walls in RCC-frame houses
- Outer walls that will be plastered
- Boundary walls
- Load-bearing walls in low-rise buildings, only if the strength class meets what your engineer specified
Lay them in the direction the maker specifies: holes-up for bricks with top-to-bottom holes, holes horizontal for bricks with holes through the width. Avoid using them below ground in wet soil unless the supplier's water absorption figure is low.
How many 3 hole bricks you need
The count is the same as for a solid brick of the same size. For 230×115×75 mm bricks with 10 mm joints:
- 4.5 inch wall: about 4.6 bricks per sq ft
- 9 inch wall: about 9.1 bricks per sq ft
- 1 m³ of brickwork: about 392 bricks
Add 5% for breakage. See bricks in 1 square foot for worked examples.
Five checks before you accept a load
- Sound. Strike two bricks together. A clear ringing sound means good burning. A dull thud means under-burnt.
- Scratch. A fingernail should not leave a mark on the surface.
- Drop. Drop a brick flat from about 1 m onto hard ground. It should not break.
- Water absorption. Weigh a dry brick, soak it in water for 24 hours and weigh again. The gain should be under 20% of the dry weight, which is the IS 1077 limit for common bricks.
- Efflorescence. After soaking and drying, look for white salt patches. A thin film is acceptable. Heavy white deposits mean salts that will come through your plaster later.
Also ask for the strength class. IS 1077 classes are numbered by minimum compressive strength in N/mm², for example class 3.5, 5, 7.5 and 10. For load-bearing walls, use the class your structural engineer specifies.
Price
Bricks are priced per 1,000. Ask whether the rate is at the plant or delivered to site, because transport can be a large part of the cost for short distances. Machine-made 3 hole bricks usually cost more per brick than hand-moulded bhatta bricks, but they need less plaster and break less. Get rates from at least two plants and compare the delivered price.
