Alchatek Blog

A municipal wastewater treatment facility in New York had catastrophic water loss in five interconnected tanks, including two Sequencing Batch Reactors (SBR) and a digester. One SBR alone lost 20–22 inches of water daily, threatening its compliance with environmental regulations and risking $25,000/day in regulatory fines. The facility’s partially buried concrete structure was built just five years prior, with cracks linked to defective cold joints and curing errors. Traditional demolition/replacement was estimated at $1.5M, but the client sought a less expensive and minimally invasive solution to avoid shutdowns. All County Spray Foam Solutions was brought in to do the job.

Initial Assessment

Technicians documented dozens of active leaks through crack networks at tank walls and floor transitions. Water migrated horizontally across tanks due to cold-joint defects in the buried structure. Larger cracks (up to ⅛") required stabilization to prevent material blowout during injection. A structural inspection confirmed no risk of wall collapse but highlighted the urgent need for crack sealing.

Proposed Solution

The engineering team selected Spetec AG200, an ultra-low-viscosity (3–4 cP) acrylic resin with NSF 61 certification for use in contact with potable water. Key advantages:

• Microscopic penetration: Fluid enough to fill hairline cracks without high-pressure injection.
• Flexible sealing: Creates elastic barriers tolerant of concrete movement.
• Cold operation: Reacts fully at substrate temperatures of 30–35°F.

The method avoided:

• Tank evacuation/excavation beneath the structure.
• Long-term downtime for concrete replacement.

Procedures

1. Crack Identification: Mapped moisture patterns and active leaks using towels/paper.
2. Port Drilling: Drilled 45° angles to intersect cracks, avoiding direct surface drilling.
3. Crack Stabilization: Used hydraulic cement to plug larger cracks, retaining oakum-soaked material.
4. Material Application:
   1. Injected Spetec AG200 at 1:12 to 3:00-minute gel times with accelerators.
   2. Monitored breakthrough (material appearing at adjacent ports).
   3. Verification: Confirmed leaks reduced to “moist areas” post-injection.

Results

The injection process, which used approximately 20 gallons of resin, sealed all major leaks within under a week. Post-repair inspections confirmed dry conditions. The approach averted months of tank shutdown, $1.5 million in replacement costs, and thousands more in potential fines.

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AT&T Plaza in downtown Dallas had persistent water infiltration issues in its basement and sub-basement levels, resulting in structural concerns and operational disruptions. The building's below-grade concrete walls developed multiple active leaks, allowing groundwater to penetrate the structure and causing dampness at wall-floor transitions, which raised concerns about potential corrosion of the reinforcing steel. Building management required an immediate solution that would effectively seal the leaks while minimizing disruption to commercial operations.

Initial Assessment

Engineering inspections by B|S|A Design Group revealed multiple active leak points throughout the basement and sub-basement concrete walls, with water infiltration occurring through cracks, joints, and penetration points. The moisture intrusion patterns indicated that several leak locations had been active for an extended period. Traditional waterproofing methods would require extensive excavation and reconstruction, making them impractical for a busy downtown commercial building. The assessment concluded that targeted injection would be most effective while allowing the building to remain operational.

Proposed Solution

The engineering team specified Spetec PUR F400, a hydrophobic polyurethane grout designed for water cut-off applications in concrete structures. This single-component material was selected for its ability to react with water to form a flexible, closed-cell polyurethane seal that permanently stops water infiltration. The material's low viscosity allows deep penetration into crack networks while its hydrophobic nature ensures effective sealing in wet conditions. This approach would eliminate disruptive excavation while providing a permanent solution.

Procedures

1. Engineers identified and mapped all visible leak points, prioritizing the most severe infiltration locations.
2. Injection ports were drilled at strategic locations to intersect water migration pathways through the concrete structure.
3. Spetec PUR F400 was mixed with appropriate catalyst ratios and injected using controlled pressure techniques.
4. Technicians monitored for complete crack filling and leak cessation, with post-injection inspections confirming successful sealing.
5. Work was coordinated to minimize disruption to building tenants throughout the process.

Results

The injection process successfully eliminated all water infiltration throughout the treated areas. Post-repair monitoring following significant rainfall events confirmed the complete cessation of leaks, with previously wet areas remaining dry. The project was completed with minimal disruption to building operations. The injection approach achieved 98%+ cost savings compared to traditional excavation and membrane installation methods. Additionally, avoiding a building evacuation prevented an estimated $25,000-$ 50,000 in lost rental income and tenant relocation costs.

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A persistent water infiltration was observed in a below-grade tunnel in Houston, TX. Staining on the sheetrock ceiling indicated the leak originated at the joint between the tunnel shell and the building wall, specifically at the interface with the flashing. The tunnel was situated on the negative pressure side of the structure, resulting in recurring water intrusion issues. The property management team sought technical advice to resolve the leak without extensive demolition or disruption to the building’s operations.

Initial Assessment

Visual inspection confirmed that water was entering through the wall/flashing joint and migrating into the tunnel ceiling. The stains and moisture patterns suggested a continuous leak path exacerbated by negative hydrostatic pressure. The location and nature of the leak made traditional surface repairs ineffective, as water was entering from behind the structure and not from an exposed face.

Proposed Solution

Alchatek recommended injecting the joint between the tunnel shell and the building wall with Spetec PUR F400, a hydrophobic polyurethane grout. This product was chosen for its ability to react with water and expand, effectively sealing active leaks even under negative pressure. The material’s low viscosity allows it to penetrate tight joints and bond with both concrete and steel, creating a durable, watertight seal. The recommended installation method involved using a Titan 440 electric injection pump, ensuring the grout was injected until the joint could no longer accept any more material.

Procedures

1. The team identified the leaking joint at the wall/flashing interface as the primary injection target.
2. Injection ports were installed along the joint to provide access for the polyurethane grout.
3. Spetec PUR F400 was injected using an electric injection pump, with technicians monitoring for material refusal and observing for any signs of milky fluid or foam, which indicated grout migration.
4. Injection continued until the joint was fully saturated and would not accept additional material, ensuring complete sealing of the leak path.
5. The process required no pre-pumping or removal of water from the joint, as the hydrophobic grout was designed to react in wet conditions.

Results

The polyurethane injection successfully sealed the leak at the tunnel shell/building wall joint. Post-repair observations showed no further water staining or active intrusion in the tunnel ceiling, and the tunnel remained dry even during subsequent rain events. The method enabled targeted remediation with minimal disruption to building occupants and eliminated the need for costly demolition or exterior excavation. The use of Spetec PUR F400 provided a cost benefit of 96% compared to traditional invasive repair methods. The property management team was satisfied with the outcome and the efficiency of the repair process.

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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.

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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.

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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.

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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.

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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.

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Concrete leak repair is crucial for homeowners with leaks in basements or other below-grade spaces. Concrete can deteriorate over time due to imperfect construction, weather, wear, and unstable soil. However, effective solutions are available. This article explains how polyurethane leak seal grouts offer a cost-effective, durable fix for waterproofing your home.

The Problem with Standard Concrete Leak Repair Methods

Many homeowners initially try using sump pumps or hydraulic cement to remedy leaks. While these may provide a band-aid, they don't get to the root of the problem. Sump pumps only remove leaking water after it has already infiltrated. Hydraulic cement may temporarily stop the leak, but it is a rigid negative side bandied and thus prone to cracking as a structure shifts and settles.

The Benefits of Polyurethane Concrete Leak Repair

In contrast, experienced leak seal specialists rely on polyurethane grouts to stop leaks at their source. They inject this material into leaking cracks and joints. The grouts then react with water to form a flexible, watertight seal. Even as a structure naturally moves, the seal stays intact. Furthermore, polyurethane grouts provide industrial-grade strength while remaining safe for residential use.

The Importance of Professional Application

While injecting polyurethane grouts may sound simple, skilled professionals should handle it. Contractors undergo training to properly drill injection holes, prepare the components, and apply the product for maximum effectiveness. An expert will ensure the grout fully penetrates the leaks and forms a reliable, long-term seal.

Environmentally-Friendly Leak Repair

When selecting a contractor, look for one that uses NSF/ANSI/CAN 61 certified products. For example, most of Alchatek's leak seal grouts are NSF-certified to meet strict environmental standards. NSF certification involves both initial and ongoing testing, so you can trust these products always to be eco-friendly.

Key Takeaways

Concrete leak repair doesn't have to be a daunting task. Armed with the right products and expertise, a skilled contractor can provide an effective, long-lasting solution. When you choose a professional specializing in polyurethane leak seal grouts, you'll gain an ally in protecting your home against water intrusion.

Fill out this form or call 404-618-0438 for a contractor referral today!

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Construction and building maintenance rely on effective waterproofing to ensure longevity and structural integrity. In fact, waterproofing protects against water damage and moisture-related structural issues in residential homes, commercial buildings, and infrastructure projects. Positive side waterproofing and negative side waterproofing are two different methods that are used based on factors like construction design, budget, and water exposure.

Positive Side Waterproofing

Positive side waterproofing applies the material to the exterior or positive side of the building structure—the side exposed to the elements and potential water ingress. As a result, this method creates an outer surface barrier that prevents water penetration. Positive side waterproofing offers several advantages. Firstly, it provides effective protection by preventing water intrusion from entering the structure, as the externally applied material acts as a barrier. Secondly, water pressure actually assists in the process by pushing the cured material against the building, which helps to maintain a watertight seal. Finally, since the waterproofing layer is applied externally, it allows for various aesthetic finishes to be applied on the interior surface without compromising the functionality of the waterproofing system.

Negative Side Waterproofing

On the other hand, negative side waterproofing treats the interior surfaces of the building. Consequently, this method prevents water infiltration from the inside surface. While negative side waterproofing can be more cost-effective in the short term, it comes with several disadvantages. One major drawback is the limited protection it provides, as it does not protect against external water pressure. Additionally, negative side waterproofing fails to prevent the corrosion of reinforcing steel, as water can still reach it. Interior waterproofing may also impact the design and finishing of interior spaces. Furthermore, water pressure constantly pushes waterproofing material away from the surface, significantly reducing its service life compared to positive side waterproofing.

Choosing the Right Method

Various factors, including building design, site conditions, budget, and water exposure influence the choice between the positive side and negative side waterproofing. Additionally, it's important to understand that chemical grouting allows for positive side waterproofing application from the negative side without excavation. The decision should be based on a thorough assessment of the building's needs in consultation with an experienced contractor. 

Fill out this form or call 404-618-0438 for a contractor referral today!

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