Alchatek Blog

Sealing Steam Leaks with Polyurethane

One of the most high-tech veneer manufacturing companies in the United States chose Alchemy-Spetec to train their maintenance techs to stop a steam leak in their facility. You heard that right. Not liquid water, but steam leaks! Prior to milling the veneer, they heat the logs in a bank of steam vaults. Rather than tearing down/rebuilding these cracked, leaking vaults they opted to inject the cracks with Spetec PUR F400, a hydrophobic flexible polyurethane grout. Replacing the vault would not only have been a lot more expensive, but it would also have resulted in a costly interruption to their milling process. No one likes downtime.

Polyurethane Leak Seal Training

Saturday is the one day of the week that the vaults are offline, and that is when I conducted the complimentary field training for their employees, who had never done any injection work before. Within a few hours, they understood how to handle the grout, how to use the grout pump, and how to accomplish their injection work. They can now self-perform their crack injection as needed.

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I was a Machinist Mate in the Navy and thus almost all of my training was mechanically focused. One class I had was Electrical Theory for Mechanics. The quick summation by the Senior Chief instructor for it was "Electricity is magic and when the smoke comes out the show is over." Being on a submarine it was deemed a good thing to keep water and electricity separate. My first time ever using polyurethane chemical grouts was on a group of sixteen conduits entering a below-grade mechanical room. While electricians may understand the "magic" of electricity they often fall short as waterproofers. Combined with the fact the numerous electrical cables coming through a conduit can be notoriously hard to waterproof and it is a recipe for leaks and electrical problems. In this post, I'll share step-by-step instructions, along with a couple of photos from a recent job one of our customers completed in a San Francisco condo complex.

Oakum soakem is a kindergarten-skill level procedure that makes waterproofing these types of penetrations easy. I refer to this as fingerpainting with chemical grouts.

1. For PVC and HDPE pipe roughing the surface will increase the mechanical bond and is recommended.
2. Wet the application area.
3. Soak oakum in either Spetec F400, GT500, or GT380 resin until saturated.
4. Pack soaked oakum into pipe joint to be sealed. If necessary, pack multiple layers. Ensure it is under compression.
5. Allow grout to cure.

Often this is all that needs to be done, but it can be followed up with injection to fill the conduit if required.

1. Stab injection needle through the cured grout and oakum plug.
2. Inject grout.

Photo: Contractor on a recent job in San Francisco, addressing multiple conduit leaks with electric injection pump, a pail of Spetec PUR F400, and Oakum.

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Sealing Leaks in Concrete with Polyurethane

Water is RELENTLESS. Leaks appear in all kinds of structures, from underground parking garages to municipal treatment tanks to elevator shafts. Everything from fine hairline crack leaks to gushers can threaten the long-term integrity of the structure and surrounding property. Fortunately, pressure injection of polyurethane grout into the crack or behind the leaking wall (depending on the application) creates a durable and rugged positive side repair. A relentless solution to a relentless problem.

A wide variety of leak seal solutions are available to address almost any type of concrete leak. (Call the Alchemy-Spetec technical support team at 404-618-0436 for assistance in choosing a product for your specific project.)

Polyurethane Leak Seal Solutions - Crack and Joint Injection

Crack and joint injection products are generally used for smaller non-gushing leaks:

Spetc PUR GT380
Activates as Foam or Gel Depending on Amount of Water Added
Ideal for Manhole Rehabilitation

Spetec PUR GT500
Most Dry-Cycle Resistant Hydrophilic Grout
Ideal for Cracks with Intermittent Leaking

Spetec PUR GT350
MDI Based Grout
For Wet Dynamic Cracks & Joints

Spetec PUR F400
Flexible Hydrophobic Grout
Ideal for Dynamic Cracks & Joints

Spetec AG200
Acrylic Injection Resin
Used in Special Situations (Contact Alchemy-Spetec Support for More Info)

Polyurethane Leak Seal Solutions - Curtain Grouting

Curtain grouting products are generally used for gushing leaks or multiple smaller leaks in proximity:

Spetec PUR H100
Semi-Flexible
Ideal for Structures with Some Movement

Spetec PUR H200
2,050 psi Compressive Strength, Fastest Cure Time­­
Ideal for Soil Stabilization

Spetec PUR Highfoamer
50x Expansion
Cost Effective for Large Voids

Spetec Boom! Seal
Two-Component, High Expansion (35x), Hydro Insensitive
Used in Special Situations (Contact Alchemy-Spetec Support for More Info)

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A contractor in Atlanta was recently called in to seal off a rain-induced ceiling leak in a new construction high-rise penthouse suite. Sealing off the water intrusion from the roof above was not an option, due to the rooftop swimming pool directly above the penthouse. So, they had to get into the ceiling from the interior of the suite and repair the leak from the underside.

Powerful Polymers

The crew on this job injected Spetec PUR F400, a water-reactive, hydrophobic, flexible, single component polyurethane resin. This product is ideal for sealing off active leaks in cracks.

Painless Procedures

Leaking concrete structures can be permanently repaired with concrete crack injection & curtain wall procedures using water-activated polyurethane foam. Pressure injection of these liquid polyurethane resins forces the material into leaking cracks or behind leaking walls depending on the application. After the polyurethane injection is complete, the polyurethane resin rapidly reacts with water to form a watertight seal.

Rapid Results

In this case, the leak was shut down in less than two minutes. This all went down literally right before the new tenant was scheduled to begin moving in. (No pressure there!)

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What Causes Leaks in Concrete?

Imperfect Construction
Concrete construction is by no means a perfect science. New construction often requires Leak Seal treatment follow-up work. If the initial construction isn’t properly sealed at the time of construction, leaks are bound to appear sooner rather than later.

Weather and Wear
Concrete naturally decays over time. Exposure to extremely hot temperatures and extremely cold temperatures can take their toll over time. Even structures located in mild climates will begin to decay purely due to the aging process.

Unstable Soil
Unstable soil can undermine the integrity of concrete structures and cause cracks to appear. Loose soil has four main causes: soil erosion, poor compaction, freeze/thaw cycles, and biological decay. If soil is the main culprit, additional stabilization and slab lifting treatments may be required in order to prevent further cracks from appearing.

What is Curtain Grouting?

Curtain grouting is the process of injecting water-reactive resin behind the leaking wall in a grid pattern (from the negative side). The water on the other side mixes with the grout and cures to a solid mass covering the surface of the wall on the other side (positive side). In addition, you don’t have water pressure dislodging external “patches” over time, as can be the case with other methods.

Curtain grouting is often required when there are gushing leaks, multiple leaks in proximity, cracks cannot be identified, the walls are made of material that does not respond well to crack injection (such as masonry, stone, and CMU), or previous leak seal methods have failed.

The most well-known Alchemy-Spetec product for this application is Spetec PUR H100, a one-component, closed-cell, hydrophobic, water-reactive, solvent, and phthalate-free, low viscosity resin. If there are large voids involved, Spetec PUR HighFoamer (a similar product with a higher expansion rate) may be a more cost-effective option.

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Crack Injection Explained

Crack injection has many advantages over other methods.  For example, if you’re sealing a leak in a water tank, you can inject from the outside of the tank. So the tank can remain in service while you repair it. Having to dry a crack, like you do with epoxy resin, is not needed as this material reacts with water. The material also remains flexible at all times.

Crack injections can be applied in both vertical cracks and in horizontal cracks. With vertical cracks, it is imperative to start at the bottom of the crack and work your way up the crack until it is filled. This forces the material up and through the crack and will simultaneously push the water up and out as well. With horizontal cracks, injection can be started at either the left or right end.

Read more from Charlie Lerman's article Crack Injection Explained.

Curtain Wall Grouting Explained

Curtain wall injection is the process of drilling holes through a structure in a diamond pattern, then injecting the grout into soil on the other side. This procedure creates a curtain wall made of a resin/soil mixture that prevents water from getting back into the structure. It is often required if there are multiple cracks or leaks in a wall. Filling each individual crack may cause you to waste time following the water from crack to crack. Curtain wall grouting allows you to stop multiple leaks at one time and protects the structure on a long term basis.

This procedure was first performed in 1960 on a sewer manhole with a multiple leak problem. As described above, chemical grout was injected through to the outside of the manhole. This created a “positive side seal” (on the side the water was coming from), blocking water from penetrating the joints of the structure.

Read more from Charlie Lerman's article Curtain Wall Grouting Explained.

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Planners at Washington D.C.’s water utility, D.C. Water, decided to take proactive measures against potential flooding of their facility. Located right next to the Potomac, their facility could’ve been at risk in the event of an out-of-the-ordinary natural disaster. Determining that the main risk to the water supply in such a case would be permeation through sub-surface soil, they began installing a metal sheet pile wall deep into the substrate between the riverbank and the facility. However, in some spots they were not able to drive a sheet pile panel into the ground because of underground utility lines or rocky substrate. The planners called in LJS Waterproofing to create sub-surface grout walls in those spots to fill in the gaps.

Powerful Polymer

The LJS crew “constructed” these sections of the underground wall by injecting AP Fill 700. This is a single component, water-activated, hydrophobic, low viscosity, closed-cell polyurethane injection resin. This grout was used because it permeates the soil, fills small voids in the soil, and cuts off water flow.

Painless Procedure

LJS professionals used a Geoprobe to drive injection pipes into the ground (up to 33 feet in some locations). They then injected one gallon per foot using upward staging. The next injection point was 18 inches away from the first one. This process was repeated until a grout wall formed, filling the gap between the two adjacent underground sheet piles. For a large-scale job like this, LJS used the PolyShark single component grout pump.

Rapid Results

With solid, impermeable grout walls filling in the gaps, a sub-surface barrier between the riverbank and the drinking water facility was now in place. The planners at D.C. Water were very satisfied with this solution. LJS Waterproofing came through exactly in the way they had promised.

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The administrators of a church in Kingston, New York discovered water leaking through a wall into a hallway. The leak was located right next to the elevator. As water seeped into the elevator pit, it became flooded. Elevator pits often contain oil from hydraulic leaks in the equipment. Disposing of that oily water over and over can cost a property owner tens of thousands of dollars over time. The administrators reached out to LJS Waterproofing for assistance before the problem drove their budget through the roof.

Powerful Polymer

The LJS crew injected Spetec PUR F400 polyurethane grout to stop the water infiltration. This material reacts with the water inside the concrete cracks, curing to form an impenetrable seal. Chemical grouts are the most reliable way to shut down leaks in concrete.

Painless Procedure

1. Concrete crack injection with polyurethane resin is a five-step process:
2. Drill the injection holes.
3. Flush debris out of the holes with water.
4. Install the injection port.
5. Flush the crack with water.
6. Inject the resin.

For a complete overview of the crack injection process LJS professionals used on this job, see the Alchemy-Spetec blog post series 5 Steps of Concrete Crack Injection.

Rapid Result

The crew finished the repairs in a timely manner, saving the church a great deal of money in the process. The hallway is now completely dry and the elevator pit is no longer flooding. An ounce of prevention, in this case, was definitely worth a pound of cure!

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Aging infrastructure is a common problem in municipalities across North America. Wastewater treatment tanks with leaking cracks are a particularly serious problem because the result is often environmental contamination. Administrators at a wastewater treatment plant in New York City contracted LJS Waterproofing to repair 39 leaking concrete tanks. An experienced LJS crew arrived on the scene shortly thereafter, ready to take on this critical threat to the environment.

Powerful Polymer

The LJS crew injected Spetec PUR F400 to seal the leaking cracks. This material is a solvent and phthalate-free, water-reactive, hydrophobic, closed-cell, low viscosity, shrink-free, flexible, one-component polyurethane injection resin designed to shut off water leaks.

Painless Procedure

Concrete crack injection with polyurethane resin is a five-step process:

1. Drill the injection hole.
2. Flush debris out of the hole with water.
3. Install the injection port.
4. Flush the crack with water.
5. Inject the resin.

For a complete overview of the crack injection process LJS professionals used on this job, see the Alchemy-Spetec blog post series 5 Steps of Concrete Crack Injection.

Rapid Result

LJS Waterproofing sealed every leaking crack in all 39 concrete tanks, preventing any future wastewater from leaking into the surrounding environment. The administrators at the New York City wastewater treatment plant were extremely happy with the results.

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This article is an excerpt from Episode 13 of Alchemy-Spetec's podcast The Injection Connection, featuring Erin Rothman - Founder and CEO of StormSensor. (If you'd rather view or listen, an audio/visual version of this excerpt is posted at the bottom of the article.)

Charlie Lerman: Do you ever get involved with EPA Consent Decrees where they've said to a municipality, "Your system's all hosed up. You need to get this fixed and you're going to do it in this time frame." Did they ever call you in for that type of monitoring or anything like that?

Erin Rothman: The consent decree programs we've been a part of have been on the combined sewer side. And a lot of that is looking at obviously when overflow is happening, how significant the overflow is. We can quantify it given in tidal locations, so being able to separate different tidal sources or flow sources. But then, really, in doing that, helping them really understanding the total volume that needs to be addressed instead of the modeled volume and incorporating that into long-term control plans.

Charlie: Gotcha. Because a lot of municipalities, especially when they're slapped with a consent decree, just think, "We just need to increase the system capacity. We need to make it bigger. We need a bigger plan." Or something like that.

Erin: Yes, increase the budget to pay the fines.

Charlie: Right. And mitigation oftentimes is a great solution that helps or even gets them to where they need to be.

Erin: Exactly. And there are all different ways you can do it. It does not just mean increasing the size of the pipe and putting them over there.

Charlie: No. That's obviously where chemical grouting comes in. That's a small portion of how to control some things. And also with chemical grouting, you find saving opportunities just right there at the manhole. A lot of these people think, “We don't have a budget to start this” or “We don't even know where to start”. But there are some really simple things. When you look at a 10 gallon a minute leak in a manhole - that is roughly, depending what part of the country you're in, between about 12 to $25 000 a year in treatment costs. 

Erin: That's one leak.

Charlie: Right, one leak. And something like that is usually super easy to repair. We're talking a couple of thousand dollars, one day, one crew out there and they can immediately repair it. You see, that $3000 you paid to fix that manhole saves $25000 that year. It's very simple stuff and I really feel that we need some champions out there to get people to understand this. Maybe some type of push with our legislators. This is kind of a passion that I’ve found and it goes great with trying to be more environmentally friendly and saving money at the same time. Who's against this kind of thing? And I don't understand why we're not doing more of it.

Erin: Exactly and providing jobs for the people to do the maintenance and creating those repairs.