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What is Top-Down Construction- Procedure, Advantages and Disadvantages

What is Top-Down Construction?
In top-down construction, permanent structures are built from the ground up, beginning with a deep basement excavation. This method is the inverse of the more common bottom-up approach. This method involves constructing the basement levels in layers as the excavation continues. The concrete floors in basements act as lateral bracing for the surrounding walls. Slabs for the ground floor and basement are poured into the excavation holes. Since all subsequent below-grade levels have been completed, the floors can now act as lateral bracing for the perimeter walls.

Diaphragm walls, or “D” walls as they are more commonly known, are a type of perimeter wall that provides a foolproof answer to any problem that may arise during underground building. D walls are ideal for controlling groundwater movement and maintaining stable earth retention.

Because of its capacity to support the building’s superstructure can be used even before the substructure is finished, speeding up construction. The top-down approach is useful for large-scale, deep-digging projects like building a metro system, a tunnel, or an underground parking garage. It could be the solution in cases when it is desirable to limit soil movement, but no tieback installation is available.

Top-Down Construction Courtesy
Fig: Top-Down Construction

Importance of Top-Down Construction:

The Procedure of Top-Down Construction:

Advantages of Top-Down Construction:

Disadvantages of Top-Down Construction:

In top-down construction, the permanent structure is built reverse, from the surface up, beginning with the basement and proceeding downward through extensive underground excavations. The basement floors are built while the excavation is still in progress. Top-Down construction has sped up project delivery to the client, lowered capital costs dramatically, and improved the quality of the build’s finish. It has also made better use of resources, lowered costs, and cut pollution.

1. Britto, Thomas. “Top Down Construction.” Online Civil Forum, 21 Oct. 2016,
2. Phan, Thanh Nguyen. “(PDF) Top Down Construction Sequence | Thanh Nguyen Phan –” (PDF) Top Down Construction Sequence | Thanh Nguyen Phan –, Accessed 14 Oct. 2022.
3. “Top Down Construction Advantages | Top Down Construction Method.” Top Down Construction Advantages | Top down Construction Method, Accessed 14 Oct. 2022.
4. Tomiša, Adriana. “Top-down Construction Method – Descriptions and Construction Sequence.” Geotech, 23 Jan. 2020,
6. Suckling, Quentin, and View more posts. “WHAT IS TOP DOWN CONSTRUCTION AND WHAT ARE ITS BENEFITS – Sheer Force Engineering.” Sheer Force Engineering, 26 Sept. 2021,

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Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

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