Common Basement Excavation Techniques

Common Basement Excavation Techniques

Excavating the earth for a basement foundation is not just using heavy equipment to dig a big hole in the ground and pouring in concrete. There is planning that is needed. You need to use the right basement excavation techniques that will create a foundation that will support your building.

Excavating your basement is a major project that takes know-how to get it right. So whether it’s new construction, an addition to your existing home or you need to excavate due to foundation damage, make sure to call an expert for help. In most cases, they will choose one of the following methods to excavate your basement.

1. Full Open-Cut Method

There are two types associated with this method: sloped and cantilever.

If you implement the sloped method, chances are it will cost you less, as you don’t need extra support to hold the foundation wall because the sides are sloped. On the other hand, the cantilever method requires retaining walls to ensure the sides don’t collapse during excavation. While more expensive, the cantilever method is the preferred method with deeper excavations.

2. Bracing Method

If you’re using this method, you must install straight, horizontal struts in front of the retraining wall. The struts will hold the material pressure off of your retaining wall. Bracing systems require center, end, and corner posts along with struts and wales. The weight from the excavated earth will get transferred to the ruts through the wale. The purpose of the end and corner braces is to reduce the wale span without increasing your strut number. The center posts help prevent strut failure.

3. Anchored Method

If you choose the anchored method, you’ll need to install anchors to counter the earth’s pressure during excavation. It works as follows: the bonded part of the anchor provides a force that works against the pressure of the earth. The unbonded part transfers the pressure to the head of the anchor. Finally, the anchor head transfers the weigh to the retaining wall. The force of the anchor is dependent on the strength of the soil. The higher the soil strength the greater the anchoring force.

4. Island Method

The island method is one of the safest ways to build your basement foundation. If you plan to use the island method, you’ll need to dig the excavation center first. Then you’ll put the excavated material near the retaining walls, which will generate a slope. The significant portion of your excavated structure will be created at the site’s center. Struts will be required between the main structure and the retaining walls.

So, which of these basement excavation techniques is best for you? The best method depends on the conditions, your budget, and how much time you have. It’s crucial to seek the advice of a contractor (or two) to see what method they can recommend for your unique situation.