Fixing Off-Center Footings during Building Construction: A Step-by-Step Guide

Off-center footings refer to a foundation support that is not properly located at the center of the intended position. This means that the footing is not in the correct position to evenly distribute the weight of the structure above it, leading to structural instability.

Off-center footings can occur due to incorrect measurements, mistakes during excavation, or errors in construction planning. It is crucial to identify and repair off-center footings promptly to avoid any long-term structural issues.

Fixing Off-Center Footings during Building Construction

Contractors sometimes face difficulties when it comes to positioning footings in a trench. As a result, walls may end up being constructed off-center from the footing, as depicted in Figure 1. However, it is crucial for the foundation wall to be accurately placed to provide the necessary support for the house. Despite the challenges encountered during the construction process, ensuring the correct location of the foundation wall remains paramount.

The footing placement shown in Figure 1 can cause the foundation wall to be off-center. However, this is not a significant concern if the soil is strong enough to support the loads of a simple wood frame house. In such cases, the full width of the footing may not be required to support the loads, and the wall can be built on the edge of the footing, providing enough support.

However, if the wall extends beyond the edge of the footing, it can generate rotational forces that the footing is not designed to handle. In such cases, it is recommended to consult an engineer. Moreover, if the soil is weak, the risk of problems increases further. Therefore, it is essential to fix the incorrectly placed footing in weak soil to avoid potential structural issues.

When constructing a wall, the type of soil it will be built on is an important factor to consider. In soils that are strong, it is possible to correct a mistake in footing layout by placing gravel to support the wall. This solution may not be suitable for weaker soils, where casting an augmented footing alongside the existing one is recommended.

To create an augmented footing, dowels are epoxied into the side of the existing footing and connected to the new one. It is important to fill any notches in the footing and cut off any existing steel dowels that will miss the wall. In soils with high bearing capacity, greater than 4,000 pounds per square foot (psf), it may be enough to excavate next to the footing, place compacted large gravel into the space and use it to support the wall. However, in weaker soils, the footing itself must be augmented with steel and concrete.

To achieve this, excavation must be done as before, but instead of filling it with gravel, drilling into the side of the footing and epoxying steel dowels into it is necessary. Then, concrete is placed to extend the footing out to the proper width. It is crucial to ensure that the footing is properly supported and designed to withstand the weight of the wall in any soil conditions.

Fixing Off-Center Footings during Building Construction: A Step-by-Step Guide

Off-center footings during building construction can lead to structural instability, making it crucial to address the issue promptly. Here’s a step-by-step guide to repairing off-center footings during building construction:

1. Identify the extent of the problem: First, you need to determine how off-center the footings are. This can be done by measuring the distance between the center of the footing and the center of the intended location. If the offset is minimal, it may be possible to correct it by adjusting the layout of the building. However, if the offset is significant, you will need to take corrective action.
2. Excavate the affected area: Excavate the soil around the footing until you reach the bottom of the foundation. The depth of the excavation should be at least equal to the depth of the footing.
3. Install temporary supports: Install temporary supports to hold the structure in place while the footing is being repaired. Use hydraulic jacks or screw jacks to support the building’s weight. Make sure that the jacks are placed on solid ground to prevent them from sinking.
4. Cut the footing: Use a concrete saw or a jackhammer to cut the footing where it is off-center. Make sure that you cut through the entire width of the footing.
5. Remove the concrete: Remove the concrete from the cut section of the footing, taking care not to damage the adjacent sections.
6. Reposition the footing: Reposition the footing so that it is centered in its intended location. You may need to use shims or grout to level the footing.
7. Pour new concrete: Pour new concrete into the excavation and around the repaired footing. Make sure that the new concrete is of the same strength and mix as the existing footing.
8. Allow the concrete to cure: Allow the concrete to cure for at least seven days before removing the temporary supports.
9. Inspect the repair: Once the temporary supports have been removed, inspect the repair to ensure that the footing is properly aligned and that there are no visible cracks or signs of stress.

By following these steps, you can repair off-center footings during building construction and ensure the structural stability of the building. It is recommended that you hire a licensed contractor to perform this repair work to ensure that it is done correctly and safely.

FAQs About Fixing Off-Center Footings

1. What is offset footing?

An offset footing refers to a type of footing where the bottom of the footing is not aligned with the top of the footing. This means that the bottom of the footing is set back or offset from the top of the footing. The offset is typically used to create a step or a ledge in the foundation, which can be useful in situations where the building needs to be elevated or where the soil conditions require a deeper foundation.

The width of the footing is typically determined by calculating the safe bearing pressure for the soil, which is then used to determine the required surface area of the footing to support the load of the structure above it.

2. Does wall need to be centered on footing?

It is generally recommended that the wall should be centered on the footing so that the projection of the footing on each side equals half the wall or footing thickness. This helps to ensure that the weight of the wall is evenly distributed across the footing and provides structural stability to the building. If a wider footing is required, it must be reinforced with additional rebar to ensure its strength and stability.

The specific requirements for the footing dimensions and reinforcement will depend on the size and weight of the wall, as well as the soil and environmental conditions of the construction site. It is important to follow building codes and obtain necessary permits and inspections to ensure that the construction is safe and compliant with regulations. Typically, 1/2-in. or 5/8-in. rebar will be required on 1-ft.

3. How do you reinforce a footing?

To reinforce a footing, the following steps can be taken:

1. Determine the necessary reinforcement: The amount and type of reinforcement required for a footing depend on the load it will bear and the soil conditions. A structural engineer or a licensed contractor can help determine the necessary reinforcement.
2. Excavate around the footing: The soil around the footing is excavated to expose the foundation.
3. Clean and roughen the concrete surface: The exposed concrete surface is cleaned and roughened to provide a good bonding surface for the reinforcement material.
4. Install dowels: Steel dowels are installed at regular intervals in both directions, perpendicular to the footing. These dowels are usually installed using an appropriate epoxy material to ensure a strong bond between the concrete and steel.
5. Fasten new steel bars: New steel bars are then fastened to the dowels using steel wires. The new bars should be placed in such a way that they are properly aligned with the existing bars.
6. Pour new concrete: The new steel reinforcement is then covered with fresh concrete. The concrete is poured up to the desired height and levelled.
7. Finish the surface: The surface is then finished with a trowel or a float to create a smooth finish.
8. Allow the concrete to cure: The concrete is left to cure for at least seven days before it is subjected to any loads.

Reinforcing a footing is a complex process that requires technical expertise and experience. It is recommended that a licensed contractor or a structural engineer be consulted for any reinforcement work to ensure that it is done safely and effectively.

4. What are the 4 types of footings?

The four types of footings that are commonly used in construction are:

1. Individual footings: Also known as isolated footings, they are used to support single columns or piers. Individual footings are usually square, rectangular, or circular in shape, and they are designed to support the weight of the column or pier.
2. Combined footings: They are used when multiple columns are located close to each other, and their individual footings would overlap. Combined footings are designed to support the weight of multiple columns and distribute the load evenly.
3. Strip footings: They are continuous footings that support a load-bearing wall or a row of columns. Strip footings are long and narrow and are used when the load is spread over a considerable length.
4. Raft or mat foundation: They are used when the soil is weak and cannot support the weight of the building or structure. Raft foundations are large concrete slabs that cover the entire area of the building, distributing the weight of the structure evenly across the soil.