What Is Sunken Slab | Advantages & Disadvantages Sunken Slab

What Is Sunken Slab (Sunk Slab)?

The sunken slab is one of the familiar and adaptable ways to maintain architectural design in especially the washroom, as well as laundry areas where water drainage systems or pipes installed below the floor or tiles.

This system is accepted to provide an easy way to install sanitary products and built eye-catching views in those areas. Furthermore, all pipe systems remain below the floor.

Hence extra care required while constructing a sunken slab; otherwise, dampness or water leakage may happen in the future.

This kind of construction require well trained or experienced workers to tackle all aspects very well by considering future visions related to the maintenance of those areas.

Also, read: M30 Grade of Concrete Mix Design Procedure with OPC 53 Cement

Why Sunken slab (Sunk Slab) Need For Bathroom?

The concrete of the R.C.C. should be mixed with a waterproofing material to get a denser, watertight concrete.

Sunken seating areas aren’t just for the interior of the home but may be great outdoors.

Sunken slabs are used in the bathrooms, toilets, and washing place where we have our washing machines.

Also, read: What Is Spalling Concrete | Causes of Spalling in Concrete | Repairing Concrete Spalding

Applications of Sunken Slab (Sunk Slab)

Following are the main applications of a sunken slab

The main area where this slab is adaptable is the washroom or in some unique architectural design where sanitary arrangement takes place.

In some cases where the inverted beam is there during the main slab at that time, this sunken slab is the only way to keep the top surface usable without any obstacles of beam height. This kind of situation may find during staircase landing.

Also, read: How to Calculate Staircase | Concrete & Bar Bending Schedule (BBS)

How to built sunken slab (Sunk Slab) or points keep in mind while construction:

The areas where the sunken slab adopted in mostly watery places hence, water drainage systems preferable to make it waterproof.

Use of plasticizer during construction to stay away from dampness problems in the future.

Advantages & Disadvantages Sunken Slab (Sunk Slab) :


All plumbing pipes are concealed inside the slab

Need special plumbing fixtures to reduce noise during usage of bathroom


The decrease in the height of the slab

Slab, waterproofing and brick bat takes more time to construct as compared to Sunken Slab

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Rajanikant Solanki:

View Comments (1)

  • This is really informative post. You can also avoid sunken slab. You can adopt 2 methods. Underslung Plumbing and Raised the toilet floor. But these methods have advantages and disadvantages.