This post is part of the Alchemy-Spetec Contractor Lens series, featuring views, news & case studies written by our customers.  This article, written by J.R. Crowell of Helms Polyfoam, is an overview of void filling with polyurethane foam.  If you're an Alchemy-Spetec customer and you'd like to discuss writing content for our blog, please send an email to marketing@alchemy-spetec.com today!

In the chemical grouting world, a void is defined as an area beneath a house/building, slab, or structure where soil was once present and is now absent. Voids are a sign of soil loss typically brought on by drainage issues and/or poor soil compaction. If voids are not addressed properly, they will continue to get bigger, and the structure’s integrity will be at stake.

Your first thought may be to fill the void with field dirt or topsoil in hopes of fixing the issue. In most cases, this method will only temporarily fix the problem visually, NOT structurally. The soil will not be properly compacted, and the structure will not have the necessary support. Also, the water paths have already been created, and water will continue to drain to this area and pull soil from beneath the structure.

Long-lasting polyurethane repair for this common problem will help you forget the void ever existed. The space will be filled with our expanding polyurethane resins by way of injection. This is a high-density, low-weight structural foam that can support thousands of pounds per square foot. Polyurethane resins enter as a liquid to chase all the water paths and fill the void space that was created. It then expands into a solid to displace all loose, weak soil and gives the structure/slab the support that it needs. This is all done in a day’s work with no headache, no stress, and no more floating slabs that serve as a ticking time bomb. 

If you're located in the Mississippi area, give Helms Polyfoam a call today at (601) 966-7821 or fill out their contact form to learn more about fixing your soil stabilization issues. 

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SOLD OUT!

Alchemy-Spetec HQ in Tucker, GA
Registration Deadline: Tuesday, October 12th

$695 Registration Fee
$615 for each additional participant from
the same company.

Get ready for a thorough education in Slab Lifting, Soil Stabilization, the Alchemy-Spetec Deep Lift® process, equipment, and applications. You’ll get hands-on training from a technical staff with decades of on-the-job experience.

Tuesday, October 26th

• Geotech Product Line Overview
• Geotech Applications & Case Studies
• PolyBadger® Demo & Training
• Estimating & Quoting Jobs

Wednesday, October 27th

• PMC Pump Demo & Training
• Leak Seal Issues on Geotech Jobs
• Ground Penetrating Radar Demo & Training
• Slab Lift Rig Demo & Training
• Competing Geotech Techniques

Thursday, October 28th

• PolyShark® / Soil Stabilization Demo & Training (On-Site)
• Deep Lift® Demo & Training (On-Site)

Your Instructors:

Andy Powell (Southeastern Regional Manager), Erik Prinzing (Midwest Regional Manager), Colt Hullander (Director of Technical Services - Geotech), Patrick Zito (Eastern Regional Manager), Joel Bryant (Western Regional Manager).

For most of my 36 years in the chemical grout industry, I have listened to people refer to chemical grouts as temporary leak repair in the same manner they mention a band-aid in stopping bleeding. Many of these same persons also say that stopping water leaks with chemical grouts is like “smoke and mirrors”, implying some sort of black magic. I must state that they are wrong on both counts.  

The mechanism by which chemical grouts stop leaks is based upon basic textbook polyurethane and acrylic chemistry. It may seem a little mysterious because most of the reaction takes place out of sight within or behind the concrete structure, but the reactions can be duplicated in the laboratory for doubters to see. As for durability and permanence, the oldest of the chemical grout manufacturers have documented case histories that are now 50 years old. I would call these permanent repairs when compared to some leak seal alternatives.

It is true, however, that for every success story I offer, someone will bring up an instance where chemical grouting did not work. Upon careful examination, these failures are almost always due to the products being incorrectly specified or installed. The biggest problem I have encountered that leads to premature failures occurs when the contractor fails to pump grout into a crack or joint until total rejection occurs. That is the point where the crack will accept no more grout. Correct product selection and installation in consultation with the manufacturer are essential to a successful long-lasting leak sealing project.

Want more info on leak seal products and equipment?

Infiltration is Draining Your Budget

In Sealing Water Infiltration in Leaking Joints, Inverts and Manholes, we identified strain and efficiency issues treatment plants undergo when groundwater infiltrates city collection systems. These common issues lead to large expenses that accumulate over time if left unchecked. A plan to minimize the damages must address the specific scale of the problems, the age and condition of your overall infrastructure, and your budget. A trusted, experienced team of consultants will prove invaluable as you navigate these uncharted waters.

Effective Manhole Infiltration Repair

According to the EPA, there are over 20 million manholes in the US. Water is infiltrating this aging infrastructure on a daily basis. If you're a municipal administrator or manager, you may already have sent in crews to eliminate the leaking with common waterproofing techniques such as applying hydraulic cement or epoxy coating. But these methods are not always 100% effective in the long term.

One of the most comprehensive ways to completely eliminate all groundwater infiltration in manholes is to encapsulate the structure using curtain grouting techniques. Specialty subcontractors utilize this technique by drilling through to the outside of the wall and injecting highly expansive polyurethane foam into the voids and soils behind it. The expansive chemical grout permeates the soils thanks to its low viscosity and creates a permanent water barrier that can fully encapsulate the manhole if necessary.

When to use Curtain Grouting

We've discussed sealing joint and penetration leaks in previous blog posts, but what if you have numerous leaks, are concerned about voids in the soil, or are repairing a brick manhole? Curtain grouting is especially useful for brick or block manholes that are made up of hundreds of joints and seams where water has many opportunities to penetrate the structure. Encapsulating the structure will polyurethane not only stops infiltration but also fills soil voids. Curtain grouting is just one technique among a handful of methods specially designed for eliminating groundwater infiltration. We recommend getting in touch with our Leak Seal Director of Technical Services, Charlie Lerman, for a free consultation to determine what leak seal methods are best for your infrastructure. Call him today at 404-618-0438. 

Want more information on curtain grouting?

As of today, the top three most viewed Alchemy-Spetec blog posts are:

1. Slab Void Fill with Polyurethane Foam
2. So You’re Thinking About Starting a Slab Lifting Company: Key Considerations
3. Hydrophobic vs Hydrophilic: Polyurethanes

Given the amount of interest in these subjects, it's worth reviewing them again. In this article, we'll feature some intro text from each of these blog posts, along with a link to the full version.

Slab Void Fill with Polyurethane Foam

Voids beneath concrete slabs can be filled with two-component polymer foam designed to work in wet or dry conditions. AP Lift 430 foam can support up to 7,200 lbs per square foot and will cure to 90% full strength in 15 minutes.  (Of the most resilient concrete slab jacking foams, AP Lift 430 is proven to lift concrete slabs under harsh conditions. This two-component, high-strength, high-density, hydro-insensitive structural polyurethane foam is the top slab jacking solution for concrete slab foundation repair, soil stabilization, and compaction grouting. AP Lift 430 weighs 2.75 – 3.25 pounds per cubic foot.) Polyurethane foam conforms to void shape more accurately than cement grout, and - unlike cement - it doesn't shrink or sink over time. Read more...

So You’re Thinking About Starting a Slab Lifting Company: Key Considerations

If you want to corner the market in this potentially profitable business, begin by scoping out a specialized area, such as residential, commercial, or civic/municipal. Next, make a simple short written list of the assets you absolutely must have to get started. Do you need a full-sized slab lifting rig to get rolling? Or maybe just the portable PolyBadger lifting system? Are there any special licenses or certifications required for operation? Do you have a good relationship with an equipment and materials supplier? Having the right slab lifting equipment, top-of-line materials, vendor support, and deep expertise in this unique industry are the first keys to success for startup companies. Read more...

Hydrophobic vs Hydrophilic: Polyurethanes

The terms hydrophobic and hydrophilic may not mean anything to the average person. But, to a contractor, these terms can mean a world of a difference. Hydro means water while phobic means “to fear” and philic means “to love”.  Alchemy-Spetec offers both hydrophobic and hydrophilic polyurethanes, so it is important to be aware of the differences between the two types.  Read more...

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In the United States, tilt-up construction is very common and the resulting joints are typically caulked. The vast majority of the time that is totally sufficient. But what about the joint you find yourself recaulking every six months to a year? While not the norm, they can be a real hassle and a thorn in your side. Enter Spetec PUR F400 and welcome to this blog post!

Spetec PUR F400 is a flexible hydrophobic polyurethane grout. Oakum is a fibrous jute rope that we soak the F400 in and then use to pack the wetted joint from the bottom up. This is a messy but simple process that leaves you with a full-depth seal/bond as opposed to the typical ¼” bond that is standard when caulking. The excess foam can be cut back and caulked to match the existing joints. Caulking is also required on the exterior as F400 is not UV stable, so the caulk protects the F400 from UV and makes the joint cosmetically match the other joints.

The same grout/oakum procedure described above can also be done for joints that are in constant submersion. Standard urethane caulk is not designed for constant submergence and while polysulfides are, they still can have problems with it. F400 is unaffected by wet, dry, wet/dry, or constant submerged environments.

These repair procedures can be applied to pipe penetrations as well. The "oakum soakum" method, as it's commonly known, is a tried and true methodology. But it is also one of the simplest methods for polyurethane chemical grout installation. I equate it to fingerpainting with chemical grouts.

Every grouting job has its unique challenges. Alchemy-Spetec's industry-leading tech support team is here to help! Call 404-618-0438 for assistance with your leak seal job today!

Want more info on leak seal products and equipment?

SOLD OUT!

Alchemy-Spetec HQ in Tucker, GA
Registration Deadline: Tuesday, October 12th

$695 Registration Fee
$615 for each additional participant from
the same company.

Get ready for a thorough education in Slab Lifting, Soil Stabilization, the Alchemy-Spetec Deep Lift® process, equipment, and applications. You’ll get hands-on training from a technical staff with decades of on-the-job experience.

Tuesday, October 26th

• Geotech Product Line Overview
• Geotech Applications & Case Studies
• PolyBadger® Demo & Training
• Estimating & Quoting Jobs

Wednesday, October 27th

• PMC Pump Demo & Training
• Leak Seal Issues on Geotech Jobs
• Ground Penetrating Radar Demo & Training
• Slab Lift Rig Demo & Training
• Competing Geotech Techniques

Thursday, October 28th

• PolyShark® / Soil Stabilization Demo & Training (On-Site)
• Deep Lift® Demo & Training (On-Site)

Your Instructors:

Andy Powell (Southeastern Regional Manager), Erik Prinzing (Midwest Regional Manager), Colt Hullander (Director of Technical Services - Geotech), Patrick Zito (Eastern Regional Manager), Joel Bryant (Western Regional Manager).

Treatment plants undergo massive strain and efficiency issues when groundwater infiltrates city collection systems. These common problems lead to large expenses that can accumulate if left unchecked. Identifying the root causes and creating a plan to minimize the damages will be dependent on the scale of the problems, the age and condition of your overall infrastructure, and your budget. Having a trusted, experienced team of consultants will prove to be invaluable as you navigate these uncharted waters.

What is Groundwater Infiltration?

Groundwater Infiltration is an industry term referring to groundwater improperly entering a sanitary sewer wastewater system. This water, which normally drains deep into the ground or is routed to storm drains, ends up being treated. This costly treatment will eat away at your already limited budget while also taking up precious capacity within your collection system. Some common ways groundwater can enter sewer pipes (interceptors, collectors, manholes, or side sewers) are through cracks, leaky pipe joints, connection failures, and poorly maintained manholes.

You may have groundwater infiltration issues if you notice any of the following signs:

1. Your pipes are backed up during rainy seasons. This is often a good indicator of an unforeseen infiltration issue. During the next heavy rain, determine if your manholes are spilling wastewater onto local roadways or fields. This may be a good indicator that you have a surplus of groundwater infiltrating your wastewater systems.
2. Your lift station pumps running continuously or cycling frequently. There may be an issue at hand if your lift station pumps run continuously for a long time after a typical rain event, or if your pumps start and stop frequently. Either event is likely happening because groundwater has entered your sanitary sewer system and is overloading your treatment centers.
3. You can measure significant spikes in flow rates. As you measure and evaluate the effectiveness of your wastewater treatment plant during rainy or high groundwater conditions, readings that return abnormal spikes in inflow likely indicate an I&I issue. While small amounts of infiltration are to be expected, large spikes rarely happen unless there is a significant infiltration issue at hand.

6 Methods to Quantify Infiltration Issues

The warning signs noted above are helpful but indicate basic symptoms only. Once you’ve suspected that groundwater is infiltrating your system, there are 6 proven methods for capturing important data to determine the next course of action. These methods must be performed by a reputable engineering firm or a survey team.

1. Sanitary sewer flow monitoring
2. Manhole inspections and 3D technology
3. Smoke testing
4. Dye testing
5. Pipe inspection/closed circuit television inspection (CCTV)
6. Private property inspections

Cost-Effective and Proven Solutions to Stop Infiltration Immediately

These groundwater infiltration points can be permanently sealed off with crack/joint injection & curtain wall procedures using water-activated polyurethane foam. Pressure injection of these liquid polyurethane resins forces the material into leaking cracks, joints, or voids behind leaking structures. After the polyurethane injection is complete, the polyurethane resin rapidly reacts with water to form a watertight seal.

These leaks can be repaired with a small crew of about three people. A repair crew this size typically averages about two manholes per day (depending on manhole size and proximity). On average, curtain wall grouting a 4-foot diameter x 8-foot tall manhole requires 5 gallons of Spetec PUR HighFoamer. On average, treating joints and pipe penetrations on a 4-foot diameter x 8-foot tall manhole requires 2.5 gallons of Spetec PUR GT380.

• Failing Sewer Pipe Joints: Groundwater rising and falling puts hydrostatic pressure on pipe and manhole joints, causing them to fail. Point grouting consists of driving injection pipes to the points of failure and injecting a resin such as Spetec PUR HighFoamer. The resin expands and cures quickly to seal off the leaks and fill voids in the soil. Filling the voids with a grout like Spetec PUR HighFoamer also reduces the hydrostatic pressure on the joints. The grout also permeates the soil and increases the load-bearing capacity which can prevent future misalignment of the pipes.
• Pipe and Manholes Inverts: For many years, inverts have been repaired with hydraulic cement. But hydraulic cement fails if there is structural movement over the long-term, and thus leaking cracks/joint return. While hydraulic cement is cheap, repeating the repair process over and over is very expensive and means more confined space entries. Injecting the joints and inverts with a flexible polyurethane grout will provide a long-term repair, often longer than the expected service life of the manhole. Spetec PUR GT380 is the gold standard for these types of repairs, but at times a hydrophobic grout might be needed and thus Spetec PUR F400 would be the grout of choice. With the F400 different reaction times are possible by adjusting the percentage of GEN ACC Accelerator.
• Precast Manhole Joints: A factory-trained specialty contractor can seal precast manhole joints using Spetec PUR GT380. It is a hydrophilic polyurethane material that cures to form a gel or a foam. Because it's a single-component material, you can install it easily without the need for mixing. It can easily penetrate joints before it eventually cures into place, thanks to its low viscosity. Spetec PUR GT380 is a durable, long-term sealing solution that holds up against the harsh sewer environment.

Want more information on leak seal products and equipment?

It's not an exaggeration to say that that the PolyShark® soil stabilization and seawall repair pump system is unmatched in the marketplace. What makes it so unique?

A Geotech Pump System Like No Other

The PolyShark® system includes injection hoses, suction lines, flow meters, a custom solid steel frame, a skid-mounted setup, and top-of-the-line components. It is a complete turnkey unit, ready to go upon arrival. Let's take a closer look...

• Two 350 feet injection hose reels are included, allowing an exceptional amount of additional reach for limited access and/or remote location jobs.
• Suction lines make it easy to pump material from totes, drums, or even pails if needed. This type of flexibility is not common to all geotech pumps.
• Flow meters make it easy to accurately track the amount of material pumped.
• The custom solid steel frame, polyurea coated for excellent chemical resistance, is built to last and weather all types of environments.
• The skid-mounted setup keeps all system components together, allowing for easy transfer from truck to trailer to the ground on a job site if necessary.
• The Honda gas motor, Titan hydraulic pump, and Titan hydraulic fluid ram are top-of-the-line, tried, and true components. This means less maintenance and downtime when compared to competing systems.

Want more information on the PolyShark®?

I&I is a major issue that plagues all collection systems. What can be done about it? There are a number of large-scale and costly ways to address it but often these are overwhelming projects to start. So, let’s take a step back and start small with the manholes. A quick review of rain event data will help pinpoint problem areas. There may be numerous issues in a line, but remember we are going for easy manhole infiltration. Start popping manhole covers. We don’t need to look for every minor leak and the large leaks are easy to identify. Obliviously, flowing water is easy to spot but even if a large leak is not active there are normally clear signs of its existence. These signs include staining, native soils being washed in, or joints with bulging ramnecks. 

So now, with X number of leaking manholes identified, it is time to set a plan. Inverts and precast joints are often the biggest culprits. Often, they have been previously repaired with hydraulic cement. But hydraulic cement can’t deal with movement, and thus leaking cracks return. While hydraulic cement is cheap, repeating the repair process over and over is very expensive and means more confined space entries. Injecting the joints and inverts with a flexible polyurethane grout will provide a long-term repair, often longer than the expected service life of the manhole. Spetec PUR GT380 is the gold standard for these types of repairs, but at times a hydrophobic grout might be needed and thus Spetec PUR F400 would be the grout of choice. 

But what about older brick manholes? Often they are ripped out and replaced. Replacement is not always necessary, can be disruptive, and is very costly. Spetec PUR Highfoamer is an excellent choice for curtain grouting (the ideal application for sealing gushing leaks in old brick manholes). Its set time can easily be field adjusted and its 50x expansion makes it very cost-effective. 

So to review...

1. Perform a quick review of rain event data to identify potential leaks
2. Pop manholes to identify large leaks
3. Grout the defects for a long-term fix

The bonus round is to watch treatment costs drop due to less infiltration! 

Pro Tip: It is best to waterproof when the leaks are active.

Want more information on leak seal products and equipment?