Advice regarding core cutting in RC wall

[nitin_ji]

Hello everyone,
I am a home owner having a flat on 14th floor of a building which has total 16 floors. Building walls are made of RCC.
I am doing some renovation in my home.

I need advise on whether it is ok to cut a hole of size 5 inches in the RCC wall for chimney pipe ? if yes what precautions should be taken to avoid any damage to the overall wall structure ?

Any advice regarding this will be helpful.

thanks,
Nitin

 

[GURDEEP NARESH]

1. Check if the wall is structural or non-structural​

• Structural walls (shear walls, load-bearing walls, core walls): Never cut or drill large holes without structural engineer approval. Even a small 5-inch hole can damage reinforcement bars or weaken the wall.
• Partition walls (non-load-bearing infill or block walls): Usually safer to cut, but still requires caution.

First, confirm with the building’s structural drawings (or consult the builder/society/structural engineer) whether your wall is structural.

---

2. Risks of cutting RCC walls​

• You may cut through steel reinforcement bars, reducing strength.
• Could cause cracks that spread over time.
• May reduce the fire resistance of the wall.
• In extreme cases, it could compromise structural stability, especially in earthquake zones.

---

3. Safer alternatives​

• Look for existing ducts, shafts, or openings provided by the builder for services (chimney, exhaust, AC pipes).
• Use window-based chimney/exhaust outlet instead of cutting the RCC wall.
• If possible, route the chimney pipe through non-structural walls.

---

4. If cutting is unavoidable​

• Get approval from your housing society / builder / structural engineer.
• Use core-cutting (diamond core drill), not hammering, to avoid vibrations and cracks.
• Position the hole carefully to avoid reinforcement bars (you can scan the wall with a rebar detector or use building drawings).
• Keep the hole as small as possible (5 inches is already quite large).
• Seal around the pipe with proper fire-resistant material after installation.