Drawbacks of Brick Bat Coba Waterproofing

Brick Bat Coba is one of the oldest traditional methods used for terrace waterproofing. It involves laying broken bricks (brickbats) over a concrete roof and grouting them with mortar to form a waterproof barrier. While many builders still use this technique, it has several significant limitations that can make it less effective than modern waterproofing solutions. Asian Paints+2LinkedIn+2

1. Adds Excess Dead Load to the Structure

Brick Bat Coba requires a thick layer (approximately 125–150 mm) of brick and mortar. This adds unnecessary weight to the terrace slab, which can stress structural members over time — especially in buildings that weren’t designed for this extra load. Asian Paints

2. Difficult and Costly to Repair

Once installed, detecting and repairing leaks is very challenging. If water infiltrates below the brick bat layer, it can travel and exit at unpredictable points, making it hard to locate the source of leakage. Simple patch repair often doesn’t work and may require removal of large areas. LinkedIn

3. Acts as a Water Reservoir if Water Gets In

Because the brickbats and mortar are porous, water can accumulate within the layer if the system fails. Instead of preventing water ingress, this layer can actually hold water, slowing evaporation and worsening leakage into the RCC slab below. LinkedIn

4. Rigid and Prone to Cracking

BBC is a rigid system with minimal flexibility. Terraces undergo expansion and contraction due to temperature changes and structural movement. This rigidity leads to cracks in the brick bat layer over time, allowing water to seep in repeatedly. Asian Paints

5. Labour-Intensive & Requires Skilled Workmanship

Although traditional, BBC still needs careful preparation, leveling, grouting, and curing. In many cases, poor workmanship — common in unskilled labour markets — results in an ineffective waterproofing layer that fails prematurely. Civil-Jungles

6. Hard to Remove Without Causing Damage

If BBC needs removal (for repairs or renovation), it can be time-consuming and labour-intensive, and may even damage the terrace slab below due to how tightly the mortar binds the brickbats. LinkedIn

7. Not Truly Waterproof by Modern Standards

While BBC can help reduce water leakage temporarily, it doesn’t form a continuous, flexible barrier like modern waterproofing membranes or liquid coatings. Many experts now consider it a traditional drainage layer, not a true waterproofing system. LinkedIn

Conclusion

Brick Bat Coba remains popular mainly because it’s familiar and historically widespread. However, due to added dead load, repair difficulties, cracking susceptibility, and limited long-term waterproofing performance, it is often not the best choice for reliable terrace waterproofing — especially when compared to modern chemical and membrane systems.