How We Shored Up Our Porch Foundation for Peace of Mind

porch foundation with arrows showing original concrete and new concrete

Over the past few years, we have been working on our porch. One phase of this project was installing simulated stone. Before we could do this, however, we had to shore up the porch foundation.

As you can see, we had erosion under our porch floor. We have never had an issue with the porch floor cracking, but we wanted to shore it up just as a precaution.

Preparing the Site

First, Neal dug out the loose dirt under the concrete floor slab. Daisy is supervising his work!

Using an electric grinder, we ground off the rough edges of the existing concrete floor slab to create a flat surface. We needed a flat surface to attach the plywood frame to keep the concrete from seeping out.

Neal dug out the loose dirt to create a clean surface for the new concrete.

Cutting the Holes

We determined where to cut the holes in the concrete floor slab based on where the erosion started (orange spots in the picture below). This was about one to two feet from the edge of the concrete floor slab.

We rented a core drill from Home Depot and cut four holes toward the edge of the concrete floor slab. We will use these holes to pour concrete to fill in the gap and shore up the foundation (porch floor).

Here are two of the four holes we cut.

Building a Wooden Frame

We built a wooden frame to contain the new concrete. To do this, we measured and cut multiple pieces of plywood that would serve as our frame (i.e. keep the cement from seeping out). We cut windows in the plywood to install plexiglass windows. These windows will help us see the concrete filling the gap. Neal started the “window holes” with an electric drill and bit.

I then used a jigsaw to cut from one hole to the other to create the windows.

Here is one of the windows.

We cut the plexiglass and screwed over each hole to create plexiglass windows. This will help us to see the concrete filling in the gap under the patio floor.

Installing the Frame

Neal installed the plywood frame (with the plexiglass windows) on the front edge of the porch floor. This plywood will keep the concrete from seeping out.

He installed a 2×4 stake to hold the plywood frame in place.

Here is the wood frame in place to keep the concrete from seeping out from under the porch floor. The first piece of plywood contains the plexiglass windows which will enable us to see the concrete filling the gap.


In a bucket with a drill and paddle, we mixed concrete with aggregate (rock) and added a shovel full of cement. We then poured the mixture in each of the four holes. The plexiglass windows enabled us to see the concrete filling the gap.

After a few days (allowing the new concrete to harden, we removed the plywood to reveal the new concrete. In the picture below, you can see where the new concrete filled the gap. It also created a surface for us to stick our stone.

Once this cured, we were ready to install the simulated stone on the face of the front patio porch.

The picture below shows where we added the stone to the front of our patio porch. Click HERE to learn how we installed this simulated stone.  

Click HERE to learn how we built our porch fireplace. 

Porch Fireplace

To see how we TOTALLY transformed our porch, click HERE.

Porch transformation

Thanks for taking the time to read our blog post!

Please let us know what you think or if you have questions about how we shored up our porch patio by commenting below.


  1. How to Install Simulated Stone on 09/20/2019 at 9:52 PM

    […] of our patio porch, we needed to shore up the concrete slab which serves as our porch floor. Click HERE to see how we shored up our porch […]

  2. R. Craig Ham on 10/13/2021 at 4:14 PM

    How do you prevent “soil creep” from eventually undermining your latest effort to shore up the porch slab? It looks like you have a pretty steep slope right off the porch. We have a problem now with my daughter’s porch which is similarly situated – the edge of the slab has dropped 2” over a 48” run in the last five years and the columns are pulling away from the roof. Any advice?

    • Suzanne on 10/13/2021 at 7:09 PM

      That is a great question. We have not had any soil creep since we shored up our porch foundation because we are proactive to prevent this. We have drain pipes connected to each gutter drain to route the water away from our porch. We also have ground cover to prevent erosion; we use landscape fabric with plantings and heavy pine straw. This helps in our case. My Neal is a BIG believer in routing water away from our house and any structure as a preventative measure.
      I hope this helps.

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