Introduction
In Bali, the integration of traditional practices with modern building techniques often leads to unique architectural features. One such feature is the use of concrete roof gutters and aprons. While these structures can be effective for water management, they also present specific challenges. Understanding the design, construction, and potential issues of these elements is essential for any homeowner or builder in Bali.
The Prevalence of Concrete Gutters
Many older houses in Bali feature concrete gutters built along the top of house walls. This is particularly common where properties are built right up to the property line. In these cases, concrete gutters serve to collect and carry water away. This is because local custom frowns upon allowing rainwater to run off a roof onto a neighbor’s land. These gutters are typically about 30 cm wide and 30 cm deep and made of concrete.
The Evolution to Concrete Aprons
In more modern constructions, the simple gutter has evolved into a broader concrete apron, built around the top of the outer walls under the edges of sloping roofs. These aprons, which can be as much as a meter wide, also serve as concrete gutters, collecting and channeling water away from the building. Both gutters and aprons can suffer problems due to poor design or construction.
Design and Structural Challenges
Concrete is exceptionally heavy. Older concrete gutters were weighty, but modern, meter-wide reinforced concrete aprons require specialized structural engineering. They need reinforced columns and beams to support their weight. This weight is also transferred to the ground, meaning that foundations must be designed to withstand these substantial loads.
- Weight: The sheer mass of concrete, especially when wet, places significant stress on the building’s structure.
- Structural Support: Adequate support, through reinforced columns and beams, is crucial to prevent structural failure.
- Foundation Design: Foundations must be designed to bear the heavy loads imposed by these concrete elements.
Common Problems with Concrete Gutters and Aprons
The most significant threat to concrete gutters and aprons is ground movement. All buildings have a tendency to move, particularly when first built. This movement can lead to cracks in walls which then leads to cracks in the concrete gutters. These cracks allow water to seep through and damage the walls.
- Settlement: New buildings typically experience settlement, which can cause cracks in the structure, including the gutters.
- Water Damage: Cracks in gutters and aprons allow water to penetrate the building, leading to dampness and wall damage.
- Poor Construction: Improperly constructed gutters and aprons can also fail, leading to water damage and structural problems.
Avoiding Settlement Issues
When building, it’s crucial to understand how settlement affects structures. Here are some ways to minimize this:
- Compaction: Avoid building directly on newly filled land. Ensure that the ground is fully compacted.
- Waiting Period: Allow filled land to settle for a sufficient period before building. Waiting at least two years is better than only 6 months.
- Foundation Piers: Build foundation piers into the original land and then fill to the desired height to avoid time delays and issues with ground movement.
Alternative Solutions
The best way to avoid problems with concrete gutters is to avoid using them altogether. Historically, Dutch houses let water run directly off the edge of the roof onto the ground. If building close to a boundary wall, consider using a gabled roof, which has a slope perpendicular to the wall.
Conclusion
Concrete roof gutters and aprons are a common feature in Bali, but they require careful consideration. Their weight, combined with the potential for ground movement, means that they can lead to problems if not properly designed and constructed. By understanding these issues and implementing best practices, homeowners and builders can avoid costly repairs and ensure the long-term integrity of their buildings.
