Alchatek Blog

A critical downtown Houston pedestrian tunnel had persistent water infiltration affecting the ceiling, walls, and floor throughout the structure. The tunnel serves as vital underground infrastructure in Houston's urban core, where any significant disruption would impact pedestrian traffic and building access. Initial observations revealed widespread moisture intrusion, but the full extent of the problem remained unclear until interior finishes could be removed for proper assessment. The facility required a rapid, effective solution that would minimize downtime and restore the tunnel's watertight integrity.

Initial Assessment

Once sheetrock was removed from affected areas, engineers discovered extensive water infiltration through multiple pathways in the concrete structure. Moisture intrusion was occurring through joints, cracks, and penetrations, creating a complex leak pattern that compromised the tunnel's structural integrity and usability. Traditional repair methods would have required extensive excavation from above or complete tunnel closure for membrane installation - both prohibitively disruptive options in Houston's dense downtown corridor. The assessment revealed that targeted injection could address the root cause of infiltration without major structural modifications.

Proposed Solution

Alchatek recommended using Spetec PUR GT350, a hydrophilic polyurethane grout specifically designed for active leak sealing in underground structures. This single-component material was selected for its ability to react with water to form an expanding, flexible foam that creates a permanent, waterproof barrier. The injection approach would allow precise targeting of leak sources while maintaining tunnel accessibility throughout the repair process. The polyurethane's expansion properties would ensure complete void filling and crack sealing, even in areas with irregular geometries or active water flow.

Procedures

1. Mapped all visible leak points and moisture intrusion areas throughout the tunnel structure.
2. Drilled strategic injection ports at locations determined to intercept water infiltration pathways.
3. Injected polyurethane grout through ports using positive displacement pumps, monitoring for material refusal and leak cessation.
4. Conducted systematic injections across all identified problem areas, adjusting techniques based on local conditions.
5. Verified complete sealing through visual inspection and moisture monitoring following cure completion.

Results

The polyurethane injection process successfully eliminated water infiltration throughout the tunnel structure, restoring its watertight integrity without requiring facility closure or major structural modifications. Post-treatment inspections confirmed the complete cessation of leaks, with the tunnel remaining dry even during subsequent heavy rain events. The minimally invasive approach allowed the tunnel to remain operational throughout the repair process, avoiding costly service interruptions. For a typical tunnel section, this represents over 95% cost savings compared to traditional methods. Additionally, avoiding tunnel closure prevented an estimated $10,000 to $ 25,000 in daily economic losses due to disrupted pedestrian traffic and building access, further amplifying the financial benefits of this innovative approach.

Want more information about polyurethane crack injection?

A tunnel structure in the Mobile, Alabama area had persistent water infiltration at the interface between concrete and metal components. The leak was traced to a tight crack at the joint, allowing water to migrate into the tunnel and cause visible staining, as well as potential long-term deterioration. The client sought a solution that would seal the leak without requiring major demolition or extended tunnel closure.

Initial Assessment

Visual inspection and on-site review identified the leak path at the interface between the concrete and metal. The crack width was measured between 0.2 and 0.3 mm, indicating that traditional cementitious grouts or surface sealants would not be effective. The challenge was to deliver a material that could penetrate deep into the joint and expand to form a watertight seal, even in confined spaces and around embedded metal.

Proposed Solution

Alchatek recommended Spetec PUR F400, a low-viscosity, hydrophobic polyurethane grout. Its ability to penetrate narrow cracks and react with water creates a durable, flexible seal. The product’s flow characteristics made it ideal for tight joints, and its expansive properties ensured comprehensive coverage within the voids and cracks. The injection plan called for drilling at the locations marked on the provided site photos, angling back toward the metal at approximately 18 inches deep to intersect the leak path.

Procedures

1. Identified injection points along the crack, using red-dot markings on the structure as a guide.
2. Drilled holes at 45° angle 12-inches apart, reaching approximately 18 inches deep to intersect the metal interface.
3. Injected Spetec PUR F400 polyurethane grout through the drilled ports, using a pump setup suitable for low-viscosity materials.
4. Monitored for material refusal and evidence of grout migration to ensure the joint was fully saturated and sealed.
5. Continued injection until the crack would not accept additional material, confirming a complete watertight barrier.

Results

The injection process successfully sealed the tunnel leak at the concrete-to-metal interface. The approach allowed for precise targeting of the leak path, with minimal disturbance to the tunnel structure and no need for extended closure or demolition. The client was able to resolve the water infiltration efficiently, reducing the risk of future deterioration and avoiding the significantly higher costs and downtime associated with traditional excavation or membrane replacement. This project demonstrates the effectiveness of modern polyurethane injection in addressing challenging below-grade leak scenarios, particularly where access is limited and the leak path is confined.

Want more information about sealing cracks with polyurethane?

In the realm of leak seal solutions, selecting the right equipment is crucial for the effective application of grouts. The SealMaster gun, developed by Alchatek, is designed specifically for crack injection and curtain grouting tasks. This tool facilitates controlled delivery of materials into cracks and voids, ensuring thorough penetration and sealing in concrete structures. Ideal for professionals in advanced leak seal operations, the SealMaster gun combines functionality with user-friendly features to support an efficient workflow on-site.

Features

• Built-in pressure gauge.
• Extended whip hose.
• Simple design.

Benefits

• Monitor back pressure.
• Low maintenance.
• Easy port connection and disconnection.

The SealMaster adjustable flow gun stands out as a reliable choice for contractors focused on leak seal applications, offering simplicity and precision that minimize downtime and enhance project outcomes.

Want more information on leak seal materials and equipment?

Attention Geotech Professionals!

Alchatek is exhibiting at the DFI 50 conference in Nashville.

Where: Gaylord Opryland Resort & Convention Center

When: October 20-23, 2025

Click Here for Registration Info

Visit us at Booth 227 to explore our advanced polymer solutions, including single and two-component polyurethanes for soil stabilization, groundwater control, and deep foundation support, addressing challenges like unstable slopes, soft ground, and deep excavation shoring for geotechnical projects.

Learn How Alchatek Helps You

At Booth 227, you can meet with our experts to learn how Alchatek empowers your geotechnical projects with cutting-edge technologies.

We support geotech professionals in three key ways:

• Innovative Polymer Solutions: Our advanced polyurethane grouts and foams provide robust solutions for curtain grouting, point grouting, and ground improvement, ensuring stability for slopes, excavations, and deep foundations.
• Expert Technical Support: We offer comprehensive training and ongoing assistance, leveraging our proven track record with industry leaders to optimize your project outcomes.
• Environmentally Safe Materials: Our NSF/ANSI/CAN 61-certified, chemically inert polymers ensure safety and compliance in sensitive environmental areas.

Want more information on Alchatek products?

A multi-level parking facility in downtown Los Angeles was experiencing significant water infiltration through its concrete ceiling. Building management had noticed increasing water staining and active leakage, particularly following rain events. The water migration around electrical conduits and light fixtures was most concerning, creating potential safety hazards with the electrical systems. Previous attempts to seal the ceiling using conventional surface treatments had failed to resolve the issue. With the structure serving high-end retail clients, the property management company required a solution to effectively stop the leaks while minimizing disruption to the facility's daily operations.

Initial Assessment

Inspection revealed that water was infiltrating through microscopic pathways in the concrete, with particularly noticeable intrusion around embedded conduits and penetrations. Engineers determined that concrete shrinkage had created tiny void spaces around these penetrations, some measuring only thousandths of an inch. Water was following these pathways, traveling along the outside of conduits and emerging at light fixtures and junction boxes installed in the ceiling. The ceiling showed distinctive water staining patterns radiating from these fixtures, confirming the migration pathway. Traditional polyurethane grouts would be too viscous to effectively penetrate these extremely small void spaces, requiring a material with exceptional flow characteristics.

Proposed Solution

Alchatek recommended using a specialized acrylic resin, Spetec AG 200. This material was selected specifically because of its extraordinarily low viscosity, significantly thinner than polyurethane alternatives, allowing it to travel through microfractures and voids that water could penetrate. Unlike thicker injection materials, acrylic resin can follow the same migration pathways as water, creating a waterproof barrier precisely where needed. The material's ability to travel long distances from injection points would minimize the number of injection ports required, reducing ceiling penetrations while ensuring complete sealing coverage around electrical conduits and other vulnerable areas.

Procedures

1. Technicians identified and mapped all water intrusion points in the ceiling, identifying migration patterns to determine optimal injection locations.
2. Strategic drilling and port installation were performed at intervals designed to intercept the water pathways, with particular focus on areas around electrical conduits.
3. Ports were installed in a pattern that would allow the low-viscosity material to flow along the same paths as the water infiltration.
4. Acrylic resin was injected through the ports, with continuous monitoring for material appearance at distant locations.
5. Injection continued at each port until the material was observed emerging from adjacent ports or known leak points, confirming pathway filling.
6. Engineers carefully monitored electrical systems throughout the process to ensure no disruption to the building's operations.

Results

The injection program successfully sealed the water infiltration pathways throughout the parking structure ceiling. Post-treatment monitoring through several significant rain events confirmed that all previously active leaks had been eliminated, with no further water migration observed around electrical fixtures. Most importantly, the acrylic resin's exceptional flow characteristics allowed for complete sealing with minimal disruption to the facility's operation. The property management company avoided spending an estimated $80,000-$100,000 that more invasive remediation methods would have required, while eliminating potential liability from water contact with electrical systems. The parking facility remained operational throughout the repair process, avoiding revenue loss that would have resulted from traditional ceiling replacement or excavation of the deck above.

Want more information about leak seal products?

The property manager for a multi-level parking garage contacted Pavecon regarding persistent water infiltration in an elevator pit. The facility engaged Allana Buick & Bers, Inc. to develop a remediation strategy. Water leakage in elevator pits poses risks to equipment, safety, and can lead to service disruptions.

Initial Assessment

Inspection revealed multiple water entry points in the concrete walls of the elevator pit. The recurring water infiltration threatened the elevator system's integrity and created potential safety issues. Traditional repair methods would require extensive excavation and significantly disrupt parking facility operations, making them impractical and costly. The assessment determined that an effective solution was needed to address active leaks and provide long-term waterproofing without frequent maintenance.

Proposed Solution

The team selected a specialized polyurethane injection system (Spetec PUR F400) for the elevator pit leakage. This product effectively seals active water leaks in concrete structures by creating a waterproof barrier without extensive excavation. The method required only brief elevator shutdown periods rather than extended facility closures and could be applied even with active water infiltration.

Procedures

1. Thoroughly cleaned repair areas to remove dirt, debris, and loose concrete that could compromise adhesion.
2. Drilled through the concrete wall at strategic locations to access water infiltration pathways.
3. Installed injection ports (zerk fittings) into each drilled hole to facilitate polymer application.
4. Injected water when necessary to properly activate the polyurethane foam reaction.
5. Polyurethane injection material was applied through installed ports, allowing it to expand and fill voids.
6. Performed sequential injection following a pattern to ensure complete coverage of affected areas.
7. Removed injection ports and patched drill holes with hydraulic cement after the injection process.
8. Performed final inspection to verify cessation of all leaks.

Results

The polyurethane injection process successfully sealed all water infiltration points in the elevator pit, creating a waterproof barrier. The repair was completed within the scheduled timeframe, minimizing elevator system downtime. The project addressed approximately 17 linear feet of repair work.

After several substantial rain events, the elevator pit remained completely dry, confirming the solution's effectiveness. The property manager expressed satisfaction with the results, subsequently requesting additional services at other facilities and providing positive recommendations.

This solution demonstrated significant cost advantages over traditional methods, saving an estimated 60-70% compared to conventional waterproofing approaches while preventing potential damage to electrical and mechanical components.

Want more information on leak seal material and equipment?

US Highway 98 is the main coastal route along Florida’s panhandle, connecting Panama City Beach, Destin, and Fort Walton Beach. Over time, the Florida Department of Transportation (FDOT) faced persistent issues with groundwater infiltrating the stormwater system. This infiltration carried exceptionally fine “sugar sand” into pipes and manholes, gradually reducing capacity and causing flooding on roadways during heavy rains. The situation escalated when a vehicle was damaged after falling into a void created by soil loss beneath the roadway, highlighting the urgent need for a lasting solution.

Initial Assessment

Inspections found that groundwater was entering through pipe joints, manhole connections, and cracks in concrete structures, transporting fine sand and creating sizable voids beneath the infrastructure. The affected system included concrete pipes ranging in diameter from 36 to 84 inches, with numerous manholes spread along a three-mile stretch of highway. Traditional repair would have required full excavation and replacement—a disruptive and prohibitively expensive process for such a critical transportation corridor. Based on the extent of sand loss and the depth of infrastructure, voids were estimated to range from several inches to several feet around key structures.

Proposed Solution

Alchatek recommended Spetec PUR H100, a semi-rigid polyurethane grout, for comprehensive rehabilitation. This material was chosen for its ability to expand and fill voids, while remaining flexible enough to accommodate minor ground movement and maintain a watertight seal. The approach involved direct injection into leaking joints and cracks, followed by creating a curtain wall around critical structures to prevent further sand migration and stabilize the surrounding soils. FDOT required a five-year warranty on the repair, underscoring both the severity of the problem and their confidence in the solution.

Procedures

1. Technicians drilled directly into each pipe joint, installing injection ports for precise placement of H100 grout.
2. Additional holes were drilled about one foot from each joint in a clock-pattern to encapsulate the joints and stabilize the surrounding soil.
3. Injection began at the lowest point of each structure and progressed upward to ensure complete filling and displacement of water.
4. Manholes received perimeter injections to form a waterproof curtain wall, with special attention to all pipe penetrations.

Results

Over the course of 18 months, approximately 2,000 pipe joints and numerous manholes were treated along a three-mile stretch of US 98. Since the project's completion in 2017, there have been no warranty claims or reported issues, even during multiple heavy storm seasons. The highway has remained free of flooding and sand accumulation, and no further undermining of the roadbed has occurred. By choosing polyurethane injection over full excavation, the FDOT avoided estimated replacement costs of $7 million to $16.5 million, while keeping the highway open and safe throughout the process.

Want more information on leak seal products and equipment?

Attention Geotech Professionals!

Alchatek is exhibiting at the DFI S3: Slopes, Support and Stabilization Conference.

Where: Madison Marriott West in Madison, Wisconsin

When: August 5–7, 2025

Click Here for Registration Info

Visit us at Booth 302 to explore our advanced polymer solutions, including single and two-component polyurethanes for soil stabilization, groundwater control, and deep foundation support, addressing challenges like unstable slopes, soft ground, and deep excavation shoring for geotechnical projects.

Learn How Alchatek Helps You

At Booth 302, you can meet with our experts to learn how Alchatek empowers your geotechnical projects with cutting-edge technologies.

We support geotech professionals in three key ways:

• Innovative Polymer Solutions: Our advanced polyurethane grouts and foams provide robust solutions for curtain grouting, point grouting, and ground improvement, ensuring stability for slopes, excavations, and deep foundations.
• Expert Technical Support: We offer comprehensive training and ongoing assistance, leveraging our proven track record with industry leaders to optimize your project outcomes.
• Environmentally Safe Materials: Our NSF/ANSI/CAN 61-certified, chemically inert polymers ensure safety and compliance in sensitive environmental areas.

Want more information on Alchatek products?

Buchanan Dam, located on the Colorado River in Texas, is a critical infrastructure built in 1937 to form Lake Buchanan. The dam is one of the longest multiple-arch dams in the world and serves as a vital resource for hydropower generation and flood control. Over time, the dam developed high-pressure water leaks in its concrete arches, particularly in Arch 47. These leaks were exacerbated by seasonal temperature fluctuations, which caused thermal expansion and contraction, leading to recurring cracks and water infiltration. Restek, Inc., a contractor specializing in structural repairs, collaborated with Alchatek to implement a polyurethane grouting solution to address these issues.

Initial Assessment

An inspection of the dam revealed severe water infiltration concentrated in Arches 45-47. Arch 47 presented the most aggressive leaks, with water flowing under high pressure. Previous injection efforts had only provided temporary relief due to insufficient grout penetration and equipment limitations. The concrete structure’s thickness and seasonal movement posed additional challenges for effective leak sealing.

Proposed Solution

Alchatek recommended using a combination of advanced polyurethane products tailored to the dam’s specific conditions. Spetec PUR HighFoamer was selected for high-pressure leaks due to its rapid reaction time and expansive properties. Spetec PUR H100 and Spetec PUR F1000 were chosen for lower-flow areas requiring flexibility to accommodate joint movement. Higher-capacity airless pumps, such as the Titan 640 and Titan 8900, were utilized to ensure effective grout delivery.

Procedures

1. Preparation:

• To reach the midpoints of the concrete structure, deeper injection points were drilled using 24-inch and 36-inch masonry drill bits.
• Oakum rope saturated with grout was packed into joints to slow water flow during the injection.

2. Injection Process:

• Spetec PUR HighFoamer mixed with Alchatek Gen Cat was injected into high-flow leak areas using upgraded pumps capable of handling high pressure.
• Flexible grout mixtures (Spetec PUR H100/PUR F1000) were injected around rigid plugs to reinforce sealed areas and accommodate seasonal joint movement.

3. Post-Sealing Monitoring:

• The team monitored material expansion within cracks and adjusted injection pressure as necessary to ensure complete sealing.

Results

The grouting crew successfully sealed leaks throughout Arches 45-47. High-flow leaks in Arch 47 were effectively stopped using Spetec PUR HighFoamer, while lower-flow leaks were addressed with flexible polyurethane grout mixtures. Equipment upgrades allowed deeper injections, overcoming previous limitations and ensuring long-term durability against thermal stresses. Subsequent inspections confirmed substantial reductions in water infiltration, with no major leak recurrence reported.

Conclusion

The Buchanan Dam leak-sealing project demonstrated the importance of combining advanced materials with appropriate equipment upgrades to address complex infrastructure challenges. Restek, Inc.'s collaboration with Alchatek resulted in a sustainable repair strategy that restored the dam’s structural integrity while accommodating environmental factors such as temperature fluctuations. This case underscores polyurethane grouting’s effectiveness as a solution for high-pressure leak repair in large-scale concrete structures.

Want more information on polyurethane leak seal materials?

Gerace Construction undertook a gate replacement project at the Tom Miller Dam in Austin, Texas. While working on Large Gate #6, and after installing a needle beam cofferdam system to lower the water level, a continuous wet spot was discovered under the metal gate sill. This indicated a crack in the concrete extending under the sill plate. Sealing the leak was necessary to prepare and coat the steel sill plate, which was crucial for the overall gate replacement.

Initial Assessment

The primary challenge was water seeping through a crack, less than one linear foot in length, located in the concrete beneath the steel gate sill. The cofferdam system had created approximately 18 feet of head pressure upstream, with the water level pumped down about two feet below the sill. As per the project specifications, a dry surface was required to apply coatings to the steel sill plate.

Proposed Solution

Alchatek recommended Spetec PUR H100 to seal the crack. This hydrophobic polyurethane resin was chosen for its ability to rapidly seal cracks with reasonable water flow and minimal anticipated movement. The solution involved injecting the resin into the crack to create a watertight seal, allowing the steel surface to dry for coating application. Alchatek also provided an on-site representative during the injection process, as required by the project specifications.

Procedures

1. Preparation:

• The contractor established the cofferdam system and lowered the water level to expose the leaking area.
• Injection ports were installed along the crack at 12-inch centers on alternating sides.

2. Injection Process:

• Spetec PUR H100 mixed with Alchatek Gen Cat was injected into the crack using positive displacement equipment capable of maintaining a minimum pressure of 250 psi.
• Injection began at the lowest port and continued sequentially upward until grout filled the crack and seepage ceased.
• Inline pressure was monitored throughout to ensure it did not drop below 190 psi during injection.

3. Post-Injection:

• The injected resin was allowed to cure fully, forming a watertight seal.
• Excess surface seal material was removed, and the repaired area was inspected to confirm no further water intrusion.
• The injection ports were removed, and holes were patched flush with hydraulic cement as per project guidelines.

Results

The application of Spetec PUR H100 successfully sealed the leak under the steel gate sill, allowing Gerace Construction to proceed with surface preparation and coating application. The fast-reacting properties of Spetec PUR H100 minimized delays while ensuring long-term durability against water infiltration. The Lower Colorado River Authority (LCRA) engineering staff approved of the product, and the Alchatek representative provided the required on-site supervision ensured compliance with all quality assurance measures, resulting in a successful repair that restored functionality and structural integrity to Gate #6 at Tom Miller Dam.

Want more information on polyurethane leak seal materials?