Skip to main content
Jacqueline Wade
Environmental engineer
Asked a question 2 years ago

Which type of foundation is best for black cotton soil?

Which type of foundation is best for black cotton soil?

Where am I?

In TheConstructor you can ask and answer questions and share your experience with others!

Depending on the structural needs one can choose shallow, deep as well as mat foundation. The thing that matters is which type of structure is going to be built.

Thank you!

Timmothy Ferguson
Assistant Project Manager

Foundation for Black Cotton Soil:

Actually the under-reamed pile foundation is one of the best foundation for black cotton soil.

Under-reamed pile has bulbs at its lower end.

Strip foundation & Pier foundation also used for black cotton soil.

Thank You.

Wilma Caldwell
Architectural technologist

Generally, for black cotton soil is also famous as expansive soil whose bearing capacity is less for suitability of spread footings and wall footings. So for black cotton soil mat foundation is most suitable. Mat foundation is recommended and also economical when the area of footings becomes greater than 50% area of building.

Raul Jimenez
Senior Project Manager

Under reamed pile is the best type of foundation for black cotton soil as it’s

The reamed pipe is placed with the moistured surface, and the ball present in it will allow the equal distribution of the load of the structure


Under reamed piles are best suited for black cotton soil.

Black cotton soil is a very dangerous soil for the building on account of its volumetric changes with the change in atmospheric conditions. It swells and shrinks according to temperature change.

When we decide on a construction in it, we have to take many precautions. Engineers prefer Pad foundation, Pier foundation, and Under-reamed pile foundation.

The under-reamed pile foundation is the best for black cotton soil. It has bulbs at its lower end.

If this bulb is given below the critical depth of moisture movement in black cotton soil, the foundation will be secured to the ground, and it would not move with movement (shrinkage and swelling) of soil.

Black cotton soil swells during the rainy season and crack during the summer season due to shrinkage. If the depth of black cotton soil is more, then the following foundations may be provided.

Strip foundation Pier foundation Under reamed pile foundation

1. Strip foundation:

These foundations are usually constructed during the dry season. A suitable plinth protection should be made around the external wall, so that moisture does not penetrate the foundation during the rainy season.

2. Pier foundation

Pier is a vertical column of a large cross-sectional area. These are taken up to good bearing strata then the piers are connected with concrete or masonry arch.

3. Under reamed pile foundation

These piles are bored and then concreted at the site. They are provided with reams and reinforcement. The top of the pile is provided with a capping beam over which walls are constructed.

The under reamed pile foundation is most commonly used in black cotton soil.

First of all if possible that we need to remove black cotton soil and make raft foundation with piles

Black cotton soil has very bad property of swelling and shrinkage due to that phenomena, different use settlement of foundation occur and lead to failure of the structure.

We can use soil treatment for foundations black cotton soil

  1. CNS material treatment
  2. Chemical treatment like lime
  3. Under reams piles
  4. Pile foundation
  5. Raft foundation with tie beam

In black cotton soil mostly used CNS material treatment and under ream foundation.

Which type of foundation is best for black cotton soil?

most suitable type foundation for black cotton soil is Under reamed pile