Introduction
In today’s construction landscape, the foundation of any durable and long-lasting building lies in its floor design. A well-constructed floor is essential not just for aesthetics but also for structural integrity and protection against moisture. This is especially crucial in regions like Bali, where environmental factors can significantly impact building materials. This guide will delve into the structural design of concrete floors, the importance of subfloors, and effective waterproofing techniques to ensure your building stands the test of time.
The Critical Role of Structural Design
A robust structural design is paramount in preventing issues like sinking, subsiding, or rising floors. When concrete floors are not properly designed and constructed, they can become unstable. It’s not uncommon to see beautiful floors in expensive villas suffering from cracks, subsidence, or damage from moisture. These problems usually stem from what’s happening beneath the visible floor – the subfloor. The tiles you see are just the finishing, the actual floor is the subfloor. The subfloor needs to be stable.
The Subfloor: What’s Underneath Matters
The subfloor is the foundation beneath your visible floor, often consisting of soil, old concrete, or stones. A standard method of laying tiles involves smoothing out whatever is underneath, then putting down a 50mm layer of cement before setting the tiles. This might look great initially, but issues arise when soft patches, moisture, or expansion and contraction cycles come into play.
Common Subfloor Construction Methods
- Simple Fill Method:
- Often, the areas between foundation beams are filled with materials like rock, sand, soil, or clay. While rock or sand can work well, soil or clay will expand and contract, causing the floor to rise and sink. If any vegetable matter is added to the fill, the floor can sink as it rots. Laying tiles on top of this compacted fill often leads to problems.
- Reinforced Concrete Panels:
- A better method involves filling the gaps between beams with rock or sand, then adding a concrete layer with steel mesh reinforcement, level with the top of the beams. However, vertical joints between the subfloor and the beam can still allow movement, moisture, and even provide a passage for termites. Using a weak concrete mix for the subfloor can also be a problem, it should be full strength and 100mm thick.
- This method can be improved by connecting subfloor panels to the beams using reinforcing bar during construction and by using modern materials to seal the joint between the subfloor and beam.
- Full Single Slab Floor:
- The best approach is to cast the entire floor as a single, reinforced concrete slab that sits across the foundation beams. This design is far more resistant to dampness, termite penetration, sagging and bulging. It’s crucial that the formwork is good, the concrete is well-placed, and the beams have strong reinforcement. If properly done, this method will avoid most of the issues with other types of subfloors.
The Importance of Waterproofing
Waterproofing is an often overlooked but vital step in concrete floor construction. In many parts of the world, the use of waterproof membranes beneath subfloors is common practice. These membranes prevent moisture penetration, but suitable plastic sheets can sometimes be difficult to source. Many builders are now using these membranes.
Types of Waterproofing Membranes
- Partial Membrane: While some may use a membrane only over the subfloor panels, this method still leaves a gap between the subfloor and the beams, which is a potential path for water.
- Full Continuous Membrane: The best way to waterproof is to install a continuous membrane beneath both the floor and the beams. This barrier prevents moisture penetration from below. Membranes need to be well-sealed to avoid any chance of water passing through holes, joints, or punctures.
Conclusion
Understanding the intricacies of subfloor construction and waterproofing is essential for ensuring the durability and longevity of any building, especially in environments like Bali. By prioritizing the correct methods, builders and homeowners can avoid costly repairs and enjoy stable, dry, and long-lasting floors. Taking the time to ensure a high-quality subfloor and proper waterproofing from the start will help prevent many issues down the road.
