Alchatek Blog

One Atlanta Plaza experienced significant settling of sidewalks and approach slabs around the perimeter of the building, creating safety hazards for pedestrians and visitors. The multi-story structure includes underground parking levels supported by piles, which remained stable, but the transition areas connecting to surrounding sidewalks were built on compacted fill. Over time, differential settlement occurred between the pile-supported structure and the soil-supported approach slabs, with some areas dropping approximately half an inch. Building management had previously attempted fixes by creating concrete "ramps" at transition points, but these temporary solutions continued to deteriorate as settlement progressed.

Initial Assessment

Engineers inspected the site and identified that the compaction difference between the soil immediately adjacent to the building foundation and the surrounding area was causing uneven settlement. This resulted in cracking of curbs, trip hazards at entrance points, and visibly sagging pavement sections, particularly noticeable at the approach to the parking garage. The most affected areas showed clear separation between the stable pile-supported structures and the settling exterior slabs. Entrance points where the differential settlement created ADA (Americans with Disabilities Act) compliance issues, and potential liability for trip-and-fall incidents were of particular concern. This problem stemmed primarily from inadequate soil compaction during the original construction.

Proposed Solution

Alchatek recommended a two-phase approach to address both the underlying soil conditions and the visible settlement. First, AP Soil 600, a single-component polyurethane product designed for soil stabilization and permeation, would be injected to densify the loose soil beneath the affected slabs. Following soil treatment, two-component polyurethane foam, AP Lift 475, would be used to lift the settled concrete sections back to their proper elevation. This non-invasive approach would eliminate the need for demolition and replacement of concrete, allowing for minimal disruption to building operations while providing a long-lasting solution.

Procedures

1. Technicians established injection points in a grid pattern, spacing them approximately 3-4 feet across the affected areas.
2. Saw cuts were made at key joints to free slabs from binding against adjacent concrete, allowing for controlled lifting without creating additional stress.
3. In the initial phase, AP 600 was injected through small drilled holes to stabilize the underlying soil and prevent future settlement.
4. After the soil stabilization phase, AP 475 was injected in multiple passes, starting from the areas closest to the building and moving outward.
5. Elevation was carefully monitored throughout the lifting process using zip levels and dial indicators to ensure proper alignment and prevent cracking.

Results

The rehabilitation project restored proper elevations at all transition points around the building, eliminating tripping hazards and improving aesthetics and safety. The lightweight polyurethane material added minimal load to the treated areas while effectively compacting and stabilizing the underlying soil.

From a financial perspective, this approach delivered significant cost savings compared to traditional repair methods. Concrete replacement would have required demolition, disposal, and new concrete installation, which is why the two-phased remediation project resulted in a 90% reduced cost compared to traditional replacement methods.

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Initial Assessment

The team at PURLevel was contacted regarding significant floor settlement issues at Outpost Harley-Davidson in Pueblo, Colorado, where a water pipe rupture had resulted in concrete movement and void spaces beneath the floor. The affected areas showed uneven surfaces with depressions ranging from 0.25 to 3 inches, creating hazards for both foot and equipment traffic.

Proposed Solution

AP Lift 430 polyurethane foam was selected for this project due to its excellent void-filling and lifting capabilities. With its 22x expansion capability and 7,200 psf compressive strength, this material is ideal for commercial floors supporting heavy equipment like that found in a motorcycle dealership.

Procedures

1. Site Preparation

   • The affected area was thoroughly inspected to determine the full extent of damage.
   • A 5'x5' grid pattern was marked across the entire interior floor area.

2. Grid Injection

   • Strategically placed injection points were established following the grid pattern.
   • Holes were drilled through the concrete slab at each injection point.
   • Polyurethane foam was systematically injected to fill voids beneath the slab.

3. Lift and Stabilization

   • After initial void filling, additional injections were performed to lift the sunken areas gradually.
   • An incremental lifting approach was used to prevent concrete cracking.
   • Areas requiring significant lift (up to 3 inches) received multiple injection passes.
   • Levels were continuously monitored to ensure even lifting across the floor surface.

Results

The project successfully stabilized the Outpost Harley-Davidson floor and restored it to its proper level. The comprehensive void-filling addressed the underlying instability caused by the water pipe rupture, providing a solid foundation for the concrete slab. Success was evident in the restored functionality of the dealership floor and the elimination of safety hazards posed by the uneven surface.

Want more information on leveling concrete slabs?

Concave ports, for use with PX-7 Slab Lifting Guns, offer enhanced performance for concrete lifting with their unique dimple top and black sealing sleeve for a secure fit. Their durable design ensures reliability under tough conditions, while the sleeve's ability to seal directly to concrete minimizes leaks and boosts efficiency, reducing the need for frequent port replacement due to leakage. 

Features

• Dimple top.
• Includes black sealing sleeve.

Benefits

• Durable design ensures enhanced reliability.
• Sleeve seals to concrete.

Requires a standard gun clamp.
Available in bags of 100.

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The PX-7 incorporates a valving rod to mechanically purge the mixed material from the mixing module at the end of each shot; eliminates the need for solvent flushing or air purge. It comes standard with a precision machined coupling block made from high strength steel. Manufactured by Polyurethane Machinery Corporation.

Key Features

• Economically Priced
• Mechanically Self Cleaning
• Solvent Free
• Airless Atomization
• Internal Impingement
• Machined Coupling Block
• Precision Ground, Single Piece Valving Rod
• Rebuildable Manual Valves
• Stainless Steel Hardened Gun Block
• CE Certified

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Suburban Basement was contracted to address a multifaceted water intrusion issue on a Rochester Hills, Michigan property. The basement had water ingress from both the furnace ductwork and the foundation. The ductwork, extending through the foundation wall into a garage-adjacent wall cavity, had sections below grade behind a garage curb. The root of the problem was water pooling under the back curb, caused by settled garage slabs from the main vehicle entrance.

Initial Assessment

The project was divided into two phases: first, addressing the leaking foundation and furnace ductwork, and second, void filling and concrete leveling of the garage floor and curb. The complexity arose from the undermined garage slabs and the need to prevent water intrusion while ensuring the safety of the furnace ductwork.

Proposed Solution

For the initial water intrusion, Suburban Basement proposed using Alchatek’s Spetec PUR Highfoamer for curtain grouting, given the limited accessibility and its fast reaction time. For the concrete leveling and void filling, AP Lift 430 was selected due to its expansion rate, soil stabilization capabilities, water displacement properties, and quick curing time for vehicle traffic.

Procedures

1. Applied curtain grout to the positive side of the wall to stop water intrusion and encapsulate the dual wall furnace ductwork
2. Commenced void filling and leveling at the garage curb, progressing toward the main vehicle entrance
3. Filled all voids beneath the garage curb and leveled the concrete across all areas of concern
4. Conducted water tests to ensure all leaks were addressed before proceeding to phase two
5. Performed void filling and concrete leveling, displacing significant amounts of water near the main vehicle entrance

Results

The project was completed successfully in two phases, with the curtain grouting finished within hours and the void filling and concrete leveling taking approximately half a day. All leaks were effectively stopped, and the concrete was successfully leveled. The homeowner expressed high satisfaction, notably as previous repair attempts had failed. Suburban Basement’s solution not only resolved the immediate water intrusion problems but also extended the lifespan of the garage concrete and driveway, providing a comprehensive fix to a complex issue.

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The owner of a gas manufacturing facility contacted a Georgia-based contractor regarding significant floor settlement issues, with a warehouse slab dropping approximately 3-4 inches. The settlement made issues for the forklift traversing in and out of the warehouse and posed a risk to the workers.

Initial Assessment

Upon arrival at the site, the team conducted a thorough investigation. Using a probe, voids were identified beneath the slab, with the probe sinking up to 2 feet in some areas. A Dynamic Cone Penetrometer test revealed large voids 2-4 feet below the slab.  Poor drainage was evident, with improper crowning causing water to flow towards the building instead of away from it. Interestingly, a layer of unusually hard clay was noticed outside the building, suggesting possible prior remediation attempts.

Proposed Solution

AP Lift 430 was chosen for this project, providing an excellent injectable polyurethane grout solution. With its impressive 22x expansion capability and 7,200 psf compressive strength, it’s ideal for warehouse slabs that support heavy equipment. The grout’s hydrophobic properties ensure long-term stability by blocking water infiltration that could otherwise lead to void formation.

Procedures

1. Deep Injection (Void Fill)

• 32 injection points were established in a grid pattern (16 on each side) at 4 ft apart.
• At each point, the team injected 15-20 pounds of material at about 5 feet depth.
• A slight lift (approximately 1/16 inch) during this phase indicated successful void filling.

2. Slab Lifting

• Additional holes were drilled next to the wall, 3 feet from the wall, and 9 feet from the wall (6 feet from the first row).
• Injection began from the holes nearest to the wall and moved outward.
• Multiple passes were made, with some areas requiring 3-4 injections.
• Gradual lifting was employed to prevent slab cracking.
• Dial indicators were used to ensure even lifting across the warehouse floor.

Results

The project successfully stabilized the warehouse floor and restored it to its proper level. Effective void-filling addressed the underlying instability, providing a solid foundation for the slab. Success was evident in the restored functionality of the warehouse space and the elimination of safety hazards posed by the uneven floor. The property manager was pleased with the work and requested additional slab lifting services for their other facilities.

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Essential Details

Dates/Pricing (Discount Deadline Extended!)

Geotechnical Masterclass: March 25th - 27th, 2025

$695.00
This is special pricing for all who register before the end of the day, March 2nd. $745 March 3rd and later. ($50 discount for each additional participant.)

Location

Atlanta, GA

Discount

$50 discount for each additional participant.

Geotechnical Masterclass

Elevate your geotechnical expertise with our comprehensive masterclass covering cutting-edge techniques and solutions. Master:

• Polyurethane Concrete Leveling for sunken slabs
• Polyurethane Soil Stabilization for various soil types
• Geotechnical Testing with precision
• Deep Lock® soil stabilization procedures

Why Attend?

• Gain Hands-On Experience with state-of-the-art equipment
• Learn From Industry-Leading Experts with decades of experience
• Network with Peers and potential collaborators
• Boost Your Company’s Market Reach and capabilities

Consider the low cost of training vs. the high cost of job screw-ups and missed opportunities.

Transitioning from routine geotechnical work to more complex and high-stakes infrastructure and large-scale construction projects represents a significant growth opportunity for your career and business. Get the advanced skills and critical insights needed to tackle challenging projects and succeed in competitive markets confidently.

Join us for this transformative Geotechnical Masterclass. We’ll equip you with the knowledge and techniques to excel across all geotechnical project types.

Essential Details

Dates/Pricing

Geotechnical Masterclass: March 25th - 27th, 2025

$695.00
This is special pricing for all who register before the end of the day, February 25th. $745 February 26th and later. ($50 discount for each additional participant.)

Location

Atlanta, GA

Discount

$50 discount for each additional participant.

Geotechnical Masterclass

Elevate your geotechnical expertise with our comprehensive masterclass covering cutting-edge techniques and solutions. Master:

• Polyurethane Concrete Leveling for sunken slabs
• Polyurethane Soil Stabilization for various soil types
• Geotechnical Testing with precision
• Deep Lock® soil stabilization procedures

Why Attend?

• Gain Hands-On Experience with state-of-the-art equipment
• Learn From Industry-Leading Experts with decades of experience
• Network with Peers and potential collaborators
• Boost Your Company’s Market Reach and capabilities

Consider the low cost of training vs. the high cost of job screw-ups and missed opportunities.

Transitioning from routine geotechnical work to more complex and high-stakes infrastructure and large-scale construction projects represents a significant growth opportunity for your career and business. Get the advanced skills and critical insights needed to tackle challenging projects and succeed in competitive markets confidently.

Join us for this transformative Geotechnical Masterclass. We’ll equip you with the knowledge and techniques to excel across all geotechnical project types.

A concrete staircase in a prominent mixed-use complex in Atlanta needed urgent repairs due to a set of 75-foot-long sunken steps. This issue posed a significant trip hazard, potentially compromising visitor safety. The problem stemmed from a combination of factors working together over time. Water infiltration through expansion cracks had created voids beneath the stairs, weakening their foundation. Compounding this issue was the natural tendency of separate concrete pieces to expand and contract, moving independently. This movement was particularly problematic as it caused the steps to separate from the adjacent sidewalk. Over time, the repeated cycles of expansion and contraction, coupled with the underlying voids, led to the steps sinking and rolling, creating a hazardous situation. 

Local experts from Engineered Restorations were called in to tackle this tricky situation. The team faced the challenge of addressing safety concerns while preserving the structural integrity of the staircase.

Powerful Polymers

AP Lift 430 was selected as the repair material for this restoration project. This polyurethane foam has expansive properties that are suitable for lifting sunken structures. Once cured, AP Lift 430 provides support for long-term stability, aligning with the project's requirements.

Painless Procedures

The repair process began with an assessment of the trip hazard. This allowed the team to determine the extent of the problem and plan their approach. Next, backer rods between the steps and sidewalk were removed to prepare the area for treatment. Alchatek Surface Guard 125 was applied around the injection area to prevent any excess polyurethane from bonding to the concrete. Protective sheets were placed to shield nearby glass surfaces.

The team drilled holes through the 8-inch concrete steps to reach the underlying soil. Soil probes revealed firm underlying conditions. The team then implemented their injection strategy. They created an initial foam layer slowly, injecting it just once every ten seconds. This gradual approach prevented existing hairline cracks from expanding during the lifting process. The team continued to inject AP Fill 430 until the steps were level. Finally, they redrilled and applied a second injection layer beneath the first to fill any voids created in the process. New backer rods were then installed.

To enhance the longevity of the repair, the team took an additional crucial step. They sealed the expansion joints with silicone, creating an optimal water barrier. This silicone sealant is flexible, accommodating future expansion and contraction. This extra measure was designed to protect the structure from water infiltration and movement, addressing the root causes of the original problem. 

Rapid Results

In just four hours, the steps were restored to a level position, aligning with the adjacent walkway. This efficient repair method addressed the immediate safety issue while extending the structure's lifespan. By lifting the existing steps rather than replacing them, the property owner avoided substantial expenses associated with demolition, new materials, and extended labor time for a complete replacement. This approach ultimately provided significant cost savings.

Want more information on concrete leveling with polyurethane?

Essential Details

Dates/Pricing

Geotechnical Masterclass: March 25th - 27th, 2025

$695.00
This is special pricing for all who register before the end of day, February 25th. $745 February 26th and later. ($50 discount for each additional participant.)

Location

To Be Determined
(in Georgia)

Discount

$50 discount for each additional participant.

Geotechnical Masterclass

Elevate your geotechnical expertise with our comprehensive masterclass covering cutting-edge techniques and solutions. Master:

• Polyurethane Concrete Leveling for sunken slabs
• Polyurethane Soil Stabilization for various soil types
• Geotechnical Testing with precision
• Deep Lock® soil stabilization procedures

Why Attend?

• Gain Hands-On Experience with state-of-the-art equipment
• Learn From Industry-Leading Experts with decades of experience
• Network with Peers and potential collaborators
• Boost Your Company’s Market Reach and capabilities

Consider the low cost of training vs. the high cost of job screw-ups and missed opportunities.

Transitioning from routine geotechnical work to more complex and high-stakes infrastructure and large-scale construction projects represents a significant growth opportunity for your career and business. Get the advanced skills and critical insights needed to tackle challenging projects and succeed in competitive markets confidently.

Join us for this transformative Geotechnical Masterclass. We’ll equip you with the knowledge and techniques to excel across all geotechnical project types.