An 8 hole brick is a machine-made burnt clay brick with eight round holes through it. Like 3 hole bricks, it is extruded and wire-cut, so the size is even and the edges are sharp. Perforated clay bricks are covered by IS 2222.
8 hole vs 3 hole vs solid bricks
| 8 hole | 3 hole | Solid (hand-moulded) | |
|---|---|---|---|
| Weight | Lightest of the three | Medium | Heaviest |
| Heat through the wall | Lowest, because of more air pockets | Medium | Highest |
| Mortar used | Most, as mortar enters the holes | Medium | Least |
| Chasing for pipes and conduits | Needs care, thin webs break easily | Easier | Easiest |
| Size accuracy | High | High | Lower |
Example: the 8 hole brick we make at BricksStreet
Naresh Sihag, who writes this site, runs BricksStreet, a clay brick maker with its own kiln in Rajasthan. Our standard 8 hole wire-cut brick shows the kind of figures to ask any supplier for:
| Specification | BricksStreet 8 hole | BricksStreet 3 hole (for comparison) |
|---|---|---|
| Size | 230 × 114 × 76 mm | 230 × 114 × 76 mm |
| Holes | Eight, 25–30 mm diameter | Three, 33–38 mm diameter |
| Weight vs solid brick | About 20% lighter | About 10% lighter |
| Minimum compressive strength | 75 kg/cm² (about 7.5 N/mm²) | 105 kg/cm² (about 10 N/mm²) |
| Water absorption | Under 20% |
The trade-off is clear in the numbers: more holes means a lighter brick but lower strength. That is why we recommend 8 hole bricks for partition and infill walls, and 3 hole or solid bricks where the wall carries load. See our range at bricksstreet.in.
Where 8 hole bricks work well
- Infill walls in RCC-frame buildings, where lower weight reduces load on beams
- West- and south-facing outer walls, where a little less heat gain helps
- Partition walls on upper floors
For load-bearing walls, use only the strength class your structural engineer specifies, and ask the plant for a test certificate.
Things to watch on site
- Follow the maker's hole direction. Bricks with top-to-bottom holes are laid holes-up so mortar keys in. Wire-cut bricks with holes through the width, like ours, are laid with holes horizontal.
- Do not over-wet. Dip or sprinkle the bricks before laying, but they should not be dripping.
- Plan conduits early. Cut chases with a wall chaser (grooving machine), not a hammer and chisel. Hammering cracks the thin inner webs.
- Fixings. A plain plug can spin in a hole. For heavy items like geysers, kitchen cabinets and TV mounts, use longer plugs that reach solid material, or chemical anchors.
How many 8 hole bricks you need
The count depends only on the outer size, the same as for any brick. 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
Add 5% for breakage. Use the brick calculator for your wall size.
Before you accept a load
Do the same checks as for any clay brick: a clear ringing sound when two are struck, no mark from a fingernail scratch, no break when dropped flat from about 1 m, and water absorption under 20% after 24 hours of soaking (the IS 1077 limit for common bricks). See 3 hole bricks for the full checklist.
