Lightweight Sunk filling

What is Sunk slab?

Sunk slabs are slabs which are casted a certain depth (200 or 300 mm or any other depending on design) below normal floor level. This extra depth is used for placing pipes and utility ducts. Sunken slabs are used in the toilets, bathrooms and washing place where we have our washing machines. The purpose of having a sunken slab is to conceal all the pipes below the floor. Since the pipes that carry water are concealed below the floor, care has to be taken to avoid leakage problems.

Why Expanded Clay Aggregate (ECA) is a preferred Green material ?

The innovative light weight Expanded Clay Aggregate (ECA) is the ultimate green construction material used for versatile applications for lightweight fill. Expanded Clay Aggregate (ECA) is a 100% Inert aggregate which is light in weight and comes in sizes of 0-30mm (0-1, 0-2mm, 2-8mm, 8-15mm, 15-30mm).It has a bulk density of 300 to 750 kg/m3 and offers a Dry Thermal Conductivity of  0.09 to 0.10 W/mK which makes it an excellent material for versatile applications. Expanded Clay Aggregate is fire resistant, termite and pest free and has a surface alkalinity of around Neutral Ph. ECA has a high resistance to chemical and weather conditions, hence is a safe aggregate. ECA does not produce any pollutants or toxic substance either during its manufacture or its use in the structure.

Expanded Clay Aggregate is the only light weight aggregate certified for geotechnical uses and is marked compliant with EN 15732 ( Lightweight fill and thermal insulation products for civil engineering applications (CEA) by CE.

Sunken slabs are preferred to be filled with light weight Expanded Clay Aggregate (ECA) against traditional alternatives as

  • CLC Broken Blocks / CLC Rubble
  • Aircon blocks, AAC Blocks
  • Brick bats
  • Light Weight Cinder
  • Broken Red Clay Bricks
  • Broken Fly Ash Bricks
  • Coal lumps
  • Burnt Tar lumps
  • Brick Jelly and others

Hence, Lightweight Expanded Clay Aggregate (ECA) is a preferred green material for filling empty spaces in building. including sunks. ECA is also used for building toilet deck filling, roof garden filling, lobby filling and other light weight back fill applications.


100 % Inert

Light in Weight

Reduction of 40-50% Load

High Compressive Strength

Cylinder Compressive Strength 0.6 to 3.0 N/mm2

Micro Porous Structure

Aids Better Aeration

Non-Toxic & Eco- Friendly

100% Eco-Friendly and Sustainable

Good Water Drainage

Excellent Drainage Property

Surface Alkalinity

Neutral pH

Excellent Thermal Insulation

Thermal Conductivity 0.097 to 0.10 W/mK

Excellent Sound Insulation

Excellent Acoustic Insulation Property


Prevents Dengue and Malaria

Low-Coefficient of Thermal Expansion

Excellent Fire Resistance

1 to 6 hrs - 9 to 19 cm LAC 1100 kg/m³

Earthquake Resistant


High Resistance to Water Absorption

Excellent Filtration Media

Unique structure suited to filter water

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