Written By Bridget Stieb, Director of Marketing at LUX Foundation Solutions •
Reviewed by LUX’s foundation repair specialists serving Northern Virginia & Florida
The Challenge: A Sinking Front Porch Pulling Away from the Brick Border
For a few years, Dawn had been stepping over the same problem every time she walked out her front door. The porch concrete had sunken and was slowly separating from the brick border, dropping lower until there was nearly a 2-inch gap running along the entire outer edge. The column bases were visibly lifted off the slab surface. It had reached the point where it was not just unsightly; it was a trip hazard, and every winter made it worse.
She reached out to LUX Foundation Solutions, not wanting to replace the entire porch if there was a better option.
Our Assessment: Soil Erosion Beneath the Porch Slab
When the LUX team arrived, the first thing they did was put a level and a tape measure on the slab. The numbers confirmed what the gaps were already showing.
What the inspection found:
- Concrete slab settled approximately 2 inches along the outer perimeter where it meets the brick border
- Column bases visibly lifted off the slab surface as the concrete dropped beneath them
- Gap running along the full perimeter between the concrete and brick border
- Crack visible through the center of the porch slab
In our experience, front porches are one of the most common concrete leveling calls we get across Northern Virginia. The slab sits on compacted fill placed during original construction, and Virginia’s freeze-thaw cycles work on that soil year after year until it can no longer hold the weight above it. The concrete does not fail; the ground beneath it does.
LUX recommended polyurethane foam lifting as the appropriate solution. Injecting high-density foam beneath the slab to fill the void, lift the concrete back to level, and stabilize the surface without any demolition.
Our Solution: Polyurethane Foam Lifting and Joint Sealing
Rather than replacing the porch entirely, LUX used polyurethane foam lifting, a minimally invasive method that lifts and stabilizes the existing slab without demolition.
On a porch like Dawn’s with a defined brick border, column bases, and an existing crack running through the slab, precision matters. We lift in controlled increments, monitoring the level at each point, because over-lifting is just as much of a problem as under-lifting.
Here is how it was done.
Step 1 — Settlement Documentation and
Before any foam was injected, the team used a 48-inch level and a tape measure to document the exact amount of settlement at each location across the porch. In our experience, this step is non-negotiable; the concrete cannot be lifted accurately without knowing precisely how much it has dropped and where the low points are.
The measurement confirmed an approximately 2-inch drop along the outer perimeter, with less settlement toward the center of the slab.
Step 2 — Drilling and Polyurethane Foam Injection and Lifting
Small injection holes were then drilled through the concrete at strategic locations, and a high-density polyurethane foam was injected through the drilled holes beneath the slab. As the foam expanded, it filled the void beneath the concrete, and the expansion pressure began lifting the slab.
The team continuously monitored the level during injection, lifting in controlled increments at each port to bring the slab back to level across the full surface.
Step 3 — Joint Sealing and Surface Restoration
With the slab leveled, the injection ports were patched, and the joint between the concrete and brick border was caulked with flexible polyurethane sealant. An open joint is a direct water entry point sealing it after the lift is what keeps the repair from being undone by the next rainy season. The porch was ready to use the same day.
The Result: Level Porch, Closed Gap, No Replacement Needed
When LUX finished at the Brunner home in Fredericksburg, the front porch was level, the gap between the concrete and brick border was closed, and the column bases were sitting flush against the slab again. No concrete was removed. No replacement was needed. The entire project was completed in a single visit.
The results:
✅ Front porch concrete slab lifted approximately 2 inches back to level
✅ Gap between concrete and brick border closed along the full perimeter
✅ Column bases restored to flush contact with slab surface
✅ Polyurethane foam fill stabilizing the slab from below, no ongoing settlement expected
✅ Joint between concrete and brick sealed with flexible polyurethane sealant
✅ Project completed in a single day, porch usable the same day as the repair
✅ No demolition, no concrete replacement, no disruption to the brick border
Learn more about our concrete leveling services and how we restore sunken slabs across Northern Virginia.
What the Client Had to Say
Does Your Porch Have the Same Gap?
If your porch concrete has started pulling away from the surrounding structure, what you just saw at the Brunner home is exactly what that repair looks like. The longer the gap sits open, the more water gets in and the larger the void beneath the slab becomes.
Polyurethane foam lifting is a fast, minimally invasive solution that works for most sunken concrete areas, including porches, sidewalks, driveways, garage floors, and more. LUX Foundation Solutions serves Fredericksburg, VA, and the surrounding areas of Northern Virginia, offering same-day service for most concrete leveling jobs.
Contact us at 540-508-8587 to request a free concrete leveling assessment today.
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About the Author
Bridget Stieb
Bridget is the Director of Marketing at Lux Foundation Solutions, bringing firsthand knowledge of the foundation repair, basement waterproofing, crawl space repair, concrete repair, and seawall needs of homeowners across Northern Virginia, the Shenandoah Valley, North Central Virginia, West Virginia, and Florida. She works closely with structural repair specialists to translate real-world inspection and repair data into homeowner guidance on foundation, basement, crawl space, and concrete issues. With a deep understanding of local homeowner concerns in both regions, she is committed to delivering clear, trustworthy content that helps families protect their homes. When she is not working on a marketing strategy, Bridget enjoys spending time with her family, friends and being outdoors.
