What Is Sunken Slab?
Sunken slab is a type of slab cast at a certain depth (200 mm or 300 mm or any other depending on design) below normal floor level. This extra depth is used for placing pipes and utility ducts and then space is filled with sand or other light weight materials until the normal floor level. It is also known as sunk slab.
Sunken Slab Construction Method:
1. The concrete of the R.C.C. (floor and sunken slab) should be mixed with a waterproofing material to get a denser, watertight concrete.
2. Then cement and waterproofing material should be diluted in water and splashed onto the RCC sunken slab. Over that, a layer of plaster should be provided using a mortar plasticizer with the cement mortar.
3. Brick laying of walls and plastering (prior to tiling) of the walls and floor should be done with cement mortar mixed with a mortar plasticizer.
4. Tile fixing for the floor and walls tiles should be done with non-shrink, waterproof tile adhesives to make the tiled area waterproof.
5. Sanitary pipe joints should be sealed with sealants specially manufactured for sealing sanitary joints firmly so that no water can leak through.
Application:
Sunk slabs can be used in the following locations :
1. Bath room/toilet/latrine /wash area floor: The floor trap and the drainage lines can be taken within the sunk portion
2. Porch slab: Here the beams are inverted so that the beams do not protrude down side and a plain surface is available.
3. Mid Landing on a staircase: The end beam is designed as an inverted beam so that there is adequate head room available below the landing.
FAQ
What is the sunk slab?
A sunk sab, also known as a sunken slab, is a part of construction in underflows where the secondary foundation for pipes, wires, etc., is placed. Sunk slabs are primarily used in the construction of bathrooms, washrooms, and laundry areas where drainage and water supply are needed the most
What is a sinking slab?
A sinking concrete slab happens when a concrete surface starts to gradually descend unevenly, resulting in visible depressions or fractures. This issue not only diminishes the visual appeal of your property but also presents significant safety concerns due to the potential for tripping hazards
Which is better, sunken slab or normal slab?
Use a sunken slab for better plumbing and drainage in wet areas. Use a normal slab for simplicity and cost-effectiveness in dry areas
What materials are used in sunken slabs?
Concrete grout is the most commonly used material to fill a sunken slab. Other materials that can be used are sand, gravel, and self-leveling cement. In sunken slab we filled any low weight material Like flyash, soil+ brick ballast
What is a float slab?
A floating slab is a single chunk of concrete that sits directly on flat soil, while a monolithic slab is a single piece of concrete that includes built-in footings that reach several feet below where the majority of the slab sits
How do you stop slabs from sinking?
First and foremost, before a slab gets poured, make sure the soil underneath the slab has been adequately compacted. Loose soil can cause the slab to shift and sink over time. Consider installing a drainage system to prevent water from pooling underneath the slab
