Sunken slabs are cement-based slabs used for waterproofing. It is a kind of slab casted to prevent water leakages in the underground pipes. The use of having a sunken slab is to conceal all the pipes below the floor. The pipes that carry water are concealed below the floor, care has to be taken to avoid leakage problems. It is cast below normal floor level. Its depth is around 200 mm to 300 mm depending on the design. This extra depth is used for placing pipes and utility ducts and then space is filled with sand or other lightweight materials.
The purpose of providing a sunk slab is to prevent water from spilling over from the sunk slab area towards the surrounding slabs. For the construction of sunk slabs, special care should be taken as the places where they are installed are prone to dampness and water leakages. Therefore concrete must be mixed with waterproofing material to get dense watertight concrete. This system is accepted to provide an easy way to install sanitary products and build eye-catching views in those areas.
The construction method and material used for sunken slab
Below the normal floor level, the sunken slab is cast at a certain depth as 200mm or 300mm or any other depending on the design and for placing pipes and utility ducts this extra depth is used. Then until the normal floor level, the space is filled with sand or other lightweight materials. The construction method is pivotal and must be carefully undertaken for complete waterproofing. The method is as follows.
Different types of materials are used for sunken slabs that include Lightweight broken CLC blocks, Lightweight cinder, Broken bricks, Brick jelly, Coal lumps, Burnt tar lumps and AAC blocks.
Advantages of sunken slabs
- All plumbing pipes are concealed inside the slab in this type of waterproofing slab.
- There is no need for special plumbing fixtures in the sunken slab.
- These slabs provide good plumbing systems and are also used where security systems are to be installed.
- These slabs provide a good plumbing system
- The sealing design creates special ventilation
- It reduces noise.
- Provide a better drainage system.
- Easy to repair.
- Can provide desired decoration in the space.
Applications of sunken slabs
There are areas where sunken slabs are used for waterproofing, these areas are prone to water ingress, so they must be applied correctly.
- Bathroom / Toilet / Wash Area Floor – The floor trap and the drainage lines can be taken within the sunk portion
- Porch Slab – The beams are inverted so that the beams do not protrude downside and a plain surface is available
- Middle landing on the ladder – The end beam is designed as an inverted beam so that there is adequate headroom available below the landing