What Is “Hacking” in Construction?
In the world of construction, the term “hacking” doesn’t refer to cybercrime—it’s a practical technique used to roughen the surface of concrete or masonry. The purpose? To ensure strong bonding between old and new construction elements, such as plaster, concrete layers, or tiles.
Whether you’re renovating an old building or preparing a surface for plastering, hacking is a critical step for structural integrity and finish quality.
What Is Hacking in Construction?
Hacking in construction refers to the process of chipping, grooving, or roughening the surface of concrete, brick, or blockwork. This technique increases the mechanical key for the new layer to adhere to the existing substrate.
It is especially important when:
- Applying plaster over RCC (Reinforced Cement Concrete)
- Adding a new concrete layer over an old one
- Fixing tiles or cladding
- Enhancing bond strength in structural joints
Why Is Hacking Important?
| Purpose | Result |
|---|---|
| Increase surface roughness | Improves bonding of plaster or concrete |
| Remove laitance (cement film) | Allows plaster to anchor to the actual structure |
| Create a key surface | Prevents de-bonding, cracks, or plaster fall-off |
| Strengthen interfaces | Improves joint integrity in composite structural systems |
Types of Hacking Methods
1. Manual Hacking
- Performed using chisels or pointed hammers
- Labor-intensive and time-consuming
- Best for small areas or minor repairs
2. Mechanical Hacking
- Uses a chipping machine or wall groover
- Faster and more uniform surface treatment
- Recommended for large surface areas like slabs, walls, and beams
3. Chemical Bonding Agents (Complementary)
- While not hacking, bonding agents like polymer latex or epoxy are often used alongside hacking to improve adhesion further.
Recommended Roughness Standards
- Grooves or indentations should be 3–5 mm deep
- Spacing: 25–75 mm depending on application
- Hacking density: ≥250 indentations/m² for plastering over RCC (per CPWD standards)
Always follow IS codes and project-specific specs for roughness requirements.
Where Is Hacking Used in Construction?
| Application | Why It’s Needed |
|---|---|
| Plastering RCC Surfaces | RCC is too smooth for bonding; needs roughening |
| Concrete Jacketing | For structural strengthening, improves bond of new concrete |
| Tile Work on Concrete Walls | Prevents tiles from falling off due to poor adhesion |
| Retrofitting Structures | Helps merge old and new elements seamlessly |
| Beams, Columns & Slabs | During re-plastering or repair works |
Tools Used in Hacking
- Pointed Chisel & Hammer (manual)
- Needle Scaler
- Electric Wall Chipper
- Pneumatic Hacking Machine
- Angle Grinder (for controlled grooving)
Safety Measures During Hacking
Wear safety goggles, helmet, ear protection, and gloves
Ensure scaffolding is secure for elevated work
Protect adjacent surfaces and fixtures
Use dust masks or respirators to avoid cement dust inhalation
Follow electrical safety protocols when using power tools
Common Mistakes to Avoid
Skipping hacking on smooth RCC before plastering
Over-chipping and weakening the structural surface
Not cleaning hacked surfaces before applying plaster
Using inconsistent patterns or shallow indentations
Ignoring structural engineer’s recommendations for bonding techniques
FAQs on Hacking in Construction
Q: Can I plaster on RCC without hacking?
A: Not recommended. RCC surfaces are too smooth and will not hold plaster well, leading to cracks or de-bonding.
Q: Is mechanical hacking better than manual?
A: Yes. Mechanical hacking is faster, more consistent, and ideal for larger areas.
Q: Is hacking needed if I use bonding agents?
A: For critical work, both are advised. Bonding agents are a supplement—not a substitute—for physical surface roughening.