Poured Foundation v/s Block Foundation

Poured foundations and concrete block foundations are the two major types of foundations employed for residential buildings commonly in the United States. The choice between poured and block foundation is made based on the load conditions and budget that is available.

We will discuss poured and concrete block foundations in detail in the article.

Concrete Block Foundation

A concrete block foundation is one of the oldest or most conventional types of foundation used for building construction. Cinder Masonry Units (CMU) are commonly used for block foundations.

Concrete Block Foundation With Steel Reinforcement

The cinder blocks are layered evenly on the top and held together using mortar ( a mixture of sand, water, and fillers). The steps are repeated until the complete foundation wall is constructed. 

Concrete block foundations are provided with steel reinforcing bars in order to improve the strength of the foundation walls. Steel reinforcement is installed when the foundation is designed to take heavy structures. 

Advantages of Concrete Block Foundations

1. A straightforward procedure - laying blocks systematically
2. No special equipment or machinery required
3. The cinder blocks are easily transported from one place to another
4. Provide desirable compressive strength. Steel reinforcement improves the strength even more to take vertical loads.
5. The blocks are not reliant on concrete, even though concrete is used to fill the cinder blocks to hold the reinforcement.

Disadvantages of Concrete Block Foundations

1. The concrete block joints are vulnerable to water as the binding mortar can deteriorate with time. This can cause future leaks.
2. A concrete block wall without sufficient reinforcement has low lateral strength. 

Poured Foundations for Building Construction

Poured foundations are concrete foundations constructed by pouring concrete mix into a formwork or mold of the required foundation dimension. The prepared formwork mold is arranged with steel reinforcement as per the design. They are various types of concrete foundations based on the depth and purpose used.

Poured Foundation Formwork and Rebar Preparation

Read On: Different Types of Foundations in Building Construction

The fresh concrete is poured into the constructed formwork, compacted, and hardened. The unit is then allowed to cure before continuing the next construction process. The fresh concrete used can be either mixed at the site or ready-mix concrete based on the size of the foundation and project.

Pouring Foundation

Advantages of Poured Foundations

1. Poured foundations give a strong, dense concrete unit that is free of leaks.
2. It provides higher lateral strength compared to concrete block foundations.
3. The pouring process is really fast compared to concrete block laying.

Disadvantages of Poured Foundations

1. The formwork preparation for poured foundation requires special skill and preparation.
2. It demands much equipment, which increases with the size of the projects.
3. Large formworks are difficult to transport that require cranes for movement along with the increase in building and labor costs.

Conclusion

Poured concrete foundations are more compact concrete units that are more water-tight and strong compared to concrete block foundations. Hence, the primary reasons that are checked to choose between both are the moisture conditions of the site, the budget, and the timeline.

The poured foundation works well in moisture conditions and high water table levels.

Poured foundations are expensive compared to concrete block foundations. The time required for the poured foundation is less compared to a concrete block for a similar project.

Also Read On: What is Foundation in Construction? Features and Purpose