Concrete Pressed Pilings

When choosing the best system for your foundation repair it's important to way the benefits of cost and effectiveness. A concrete pressed piling can be very effective in certain areas while also being one of the more economical.

A concrete pressed piling is essentially a stack of cylinder blocks. Each block, or piling, is 6 inches in diameter and 12 inches tall. At the top of the stack you would have what's called a top cap, or a much larger square block. This block gives us a bigger lifting surface to make it easier to lift, then shim the pier. Once shimmed with more cylinders, at the very top in between the cylinders and the bottom of the foundation, we place steel shims. These allow us to get a nice and snug fit.

How are they installed?

First a hole must be excavated near a beam of the foundation. For most projects these holes are dug around the perimeter of the foundation from outside of the house, however sometimes they need to be installed inside the house. This hole is approximately 30 inches wide by 30 inches long and the depth is about 24 inches below the bottom of the foundation, which could end up making the hole 48 to 54 inches deep. We also need to excavate 6 to 10 inches under the house to allow us access directly below the bottom of the slab. We then can start pushing cylinders.

You use a hydraulic press to push these cylinders into the ground one by one. These pilings are pushed until we reach the point of refusal. For a concrete pier this is the depth in the ground that allows the concrete pilings to have enough surface area, or friction, along the sides to support the weight of the house above it.

Once this point of refusal is met for all the piers we are installing, we place the top cap on top of the last cylinder and place a 20 to 30 ton bottle jack to the right or left side of the top of the cap. The heavy duty bottle jack can then lift the house back into place. We then replace the bottle jacks with various assorted concrete blocks to shim up to the bottom of the slab with the last shim being a steel shim to help secure the pier to the house.

The Pros

The main reason why someone would want to install this pier would be the cost. Concrete has a low material cost and therefore helps control the overall project cost, making this system the most cose effective system on the market.

The Cons

With any cost effective system, there will of course be some downsides that need to be discussed. The main downside being related to the type of clay we mostly have in this area. It's a very dense hard clay and concrete has a high coefficient of friction along with more surface area compared to it's steel counter parts. Therefore when pushing into the ground, it's point of refusal is much closer to the surface than other options. Therefore this pier is a lot less forgiving of poor maintenance habits and extreme seasonal shifts. Potentially meaning that you will need to have more warranty adjustments on this pier over the lifespan of the house compared to other systems. While the material and labor would be covered under our warranty there are annoyance costs that should be considered, which might make this pier more expensive over the lifespan of the house than other systems, even though it has a lower upfront cost.
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