The Difference Between Poured and Block Foundations Explained

Recently a customer wanted to know which is the better type of foundation for a new home, a block wall or a poured wall? Are there any significant differences to consider between poured and block foundations? And what are the advantages and disadvantages of each type of wall?

How is a poured wall foundation constructed?

Our experience would indicate that a poured wall presents fewer headaches than a block wall. Which translates into fewer repairs and reduced costs for the homeowner. After the grading and installation of a subbase of sand or gravel, constructed forms are placed in the area prepared for pouring. Poured walls are 6-10 inches thick with steel re-bar or some other type of reinforcement placed inside for additional strength. A poured wall contains more mass and is joint free. Footings designed to provide drainage also relieve lateral pressure. Poured foundations take less time to construct than block wall foundations. And if a leak is discovered in a poured foundation, repairs are possible with a simple epoxy injection whereas a block wall will require expensive and time-consuming excavation.

How is a block wall foundation constructed?

Just like a poured wall foundation, grading and sub base preparation are preliminary. Block walls need a level foundation pad below the freeze line. In Minnesota, that can be as deep as 3-feet, which may increase the price of grading and soil removal. Block dimensions vary in width from 4″, 6″, 8″, 10″, 12″, and sometimes as much as 14″, and 16″. Blocks are relatively light and easy to install by a professional masonry. Using an interlocking pattern, block installation is similar to brick installation. Blocks are hollow and joined together by a mortar mix. Re-bar connect the blocks to the footing. Unless the blocks are filled with mortar and properly reinforced, the wall is relatively weak. To ensure stability and strength of a block wall, all blocks need to be filled. However, no wooden forms are necessary to construct and install. Block walls are easy on your checkbook in some ways but look out if a leak develops. Block walls require excavation and that will not be easy on your checkbook.

Is price a worthwhile consideration?

According to the Concrete Network, “estimating concrete prices is not an easy exercise, as many factors are involved in pricing concrete.” Both foundation types have a certain number of commonalities. Such things as grading, sub base preparation, and price of the concrete. A poured wall will require time and material for forms, finishing, and reinforcement. The price of concrete for a poured wall will exceed that of a block wall because of the volume of concrete used. Let’s break down some national average numbers.

Disclaimer: The following are not price quotes but simply ballpark numbers to assist consumers in their decision-making process in choosing either a poured wall foundation or a block wall foundation.

As we have noted, block walls and poured walls are very similar in strength and durability. Since the entire structure is dependent on the quality of the foundation wall, it is imperative to select a reputable contractor to perform the work. Time and the price of foundation materials pose the greatest difference between the two types of walls. Both types of foundation walls require grading and a subbase of sand or gravel to provide drainage and a firm level platform on which to build the wall. Grading varies between $50 and $70 per hour depending on the amount of dirt removed and the hourly rate for a tractor and operator. The subbase of sand or gravel is between $12 and $18 per cubic yard. Concrete forms and finishing will run around $1.50 to $2.00 per square foot. Once again, please note that forms and finishing are not needed for a block wall foundation. Reinforcement, such as re-bar. wire or plastic mesh, or some type of fiber in the mortar will average around 15 cents to 30 cents per square foot. The price of concrete is approximately $93 to $100 per cubic yard. The cost of concrete takes up the majority of the cost.

Serving the greater Minneapolis-St. Paul area, Minnesota Concrete offers free, no obligation estimates and is the firm to contact for all your concrete needs. You can call us today at 612-886-8777 or use this convenient link: Minnesota Concrete. We look forward to working with you.

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