This post is part of the Alchemy-Spetec Contractor Lens series, featuring views, news & case studies written by our customers. This article, written by Brian Dalinghaus of Dalinghaus Construction, examines the following applications of polyurethane: void fill, slab leveling, and slab lifting. 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!

So, your sidewalk sunk into the muddy mire that used to be your backyard before Fifi dug it up. Or perhaps your cement patio has a new severe slant to it so that you shimmy folded-up pieces of paper underneath your picnic table to make it artificially level. Or maybe you have weak, non-loadbearing soil and your pool is starting to crack due to the strain. The question is: how do you lift and re-level large sections of concrete?

Polyurethane is a panacea, a cure-all, for a long list of soil-related issues. Polyurethane can lift, level, and densify weak soil. Dalinghaus Construction Inc. has been in the foundation repair industry for decades. We are here to educate you on everything to do with polyurethane, whether you choose to employ our services or go with another contractor.

In this article, you will learn the properties of polyurethane foam, how it is utilized for soil densification, slab lift & leveling, and void fill.

What is Polyurethane Foam?

Polyurethane foam is an injectable polyol and isocyanate resin sealant, insulation, grout which expands upon application providing void fill, structural support, and re-leveling properties. Polyurethane foam is waterproof, flame-retardant, noninvasive, and nonpolluting, weighing 3.5 to 5 pounds per cubic foot and reaching 90% compression strength after 15 minutes. Polyurethane can hold up to 7,200 pounds per square foot.

Polyurethane is injected as a liquid before it solidifies into its foam state. Due to the initial liquid form, polyurethane permeates into tight spaces, allowing it to penetrate weak soil and difficult to reach voids. This foam is environmentally inert, posing no danger to the environment or the evolutionarily finely tuned habitat that is your yard.

In other words, your children and your furry pets are safe. In fact, polyurethane itself is so safe it is used in pacemakers and other devices that can be safely implanted into the body.

At Dalinghaus Construction Inc., we utilize AP Lift 430, which is certified by Truesdail Labs to NSF / ANSI 61-5 (meaning it’s approved for contact with drinking water).

Fun Fact with Brian – Polyurethane has quickly usurped mudjacking due to its lighter weight and less invasive application system. Mudjacking slurry weighs up to 140 pounds per cubic foot (which just adds more weight to an already sinking slab). To find out why Polyurethane is a better option than mudjacking, read our article Polyurethane Injection vs Mudjacking (Weight, Application, & Cure Time).

Polyurethane Soil Densification

Polyurethane foam densifies weak, non-loadbearing, expansive soils, such as clays and lay stratum. The polyurethane is pumped deep into the soil (often at varying levels/intervals) and expands as a foam. The polyurethane foam fills gaps and underground pockets that compromise the structural integrity of the soil. This foam solidifies, strengthening the soil by adding light, water retardant support. Polyurethane soil densification can be used to mitigate landslides, for hillside stabilization, and deep injection.

Polyurethane Slab Lift & Leveling

Sidewalks, concrete patios, and backyard basketball courts can sink and become uneven. While it’s tempting to blame the slanted slab for your bad dribbling skills during a pick-up game, it’s always more fun and safer to walk across flat, level surfaces.

A flat working space is especially important in a warehouse environment. Polyurethane foam works beautifully at leveling warehouse slabs to ensure all the warehouse workers are safe. To learn more about warehouse safety, read our other Contractor Lens article on the Alchemy-Spetec blog, Warehouse Floor Repair.

Polyurethane is the perfect candidate to lift and re-level concrete surfaces, due to the expansive properties of the foam. As the foam expands, it pushes upwards, exerting a tremendous amount of force on the slab above, returning it to level.

Polyurethane Void Fill

Polyurethane foam is often utilized as a void fill after a slab lift during an underpinning project. When the affected section of the home is lifted, it leaves a void where the home had settled. Polyurethane is injected, the foam expands, and the void is filled with strong, durable, and supportive material.

*Note – The lifted section of the home always requires void fill (the last pier on each side is referred to as the void fill lifting point). The entire area beneath the slab doesn’t require void fill, only the affected area.

Polyurethane Projects

In this article, you learned about various applications of polyurethane foam in the construction world: soil densification, slab lift & leveling, and void fill.

If you want to learn how invasive polyurethane injection is, read our article 5 Steps to Polyurethane Foam Injection (From Drillholes to Cure).

We have over 100 years of combined experience in the foundation repair game. We are here to educate and assist, whether you ultimately choose us for your polyurethane services or not.

If you live in Southern California or Arizona and would like to book a free foundation inspection, click the link below...

Want more information on slab lifting with polyurethane?

Andy Powell Promoted to Division Manager - Geotech

Alchemy-Spetec is pleased to announce the promotion of Andy Powell to the position of Division Manager - Geotech. Andy Powell has been with Alchemy-Spetec since the inception of the company in 2013. His experience includes manufacturing, application, equipment, estimating, field service, and training for the entire product line. While he specialized in geotech products and applications, his experience also includes crack injection and curtain grouting. In his new position, Andy will be responsible for overseeing the entire Geotech Division at the national level. In this capacity, he will still be able to assist customers in the Southeast who know him well.

Steve Taylor is Now Southeast Regional Manager

Alchemy-Spetec is pleased to announce the hiring of Steve Taylor as Southeast Regional Manager. Steve Taylor’s experience includes material installation, equipment operation, estimating, and field service training. Applications include slab lifting, soil stabilization, crack injection, curtain grouting, and seawall repair. Before joining Alchemy-Spetec, Steve was General Manager at the geotech contracting firm Ground Consolidation Services. At GCS he supervised crew members and managed customer relations for all of metro Atlanta. He has worked in the construction industry for many years. Before GCS, Steve was a supervisor for a major home remodeling contractor. Steve is known for his responsive and considerate approach when working with customers. Early in his career, Steve spent time as an audio engineer in the film industry. He’s also a talented drummer. He lives in Marietta, GA with his wife, son, and daughter.

Want more information on Alchemy-Spetec products?

Alchemy-Spetec HQ in Tucker, GA
Registration Deadline: Tuesday, March 1st

$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, March 29th

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

Wednesday, March 30th

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

Thursday, March 31st

• 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).

As one of the most impenetrable permeation grouting products on the market, AP Soil 600 is a single component, moisture activated, hydrophobic, low viscosity, polyurethane soil grout. This permeation grout is ideal for stabilizing loose sand and soil around all types of concrete structures, as well as for sinkhole remediation. This post will focus on the specific reasons why AP Soil 600 is your best option for stabilizing sandy soils.

Sandy soils erode easily with any kind of rain event. Once the erosion and soil migration starts, you may start to notice settlement occurring alongside the structure in a variety of ways. Poor compaction and erosion of sandy soils affect all types of commercial buildings, residential homes, driveways, roadways, and more. Typically you may find some kind of cracking or settling in structures as sandy soils begin to erode.

AP Soil 600 is a powerful chemical grout that permeates sandy soils to lock everything in place. Once the grout cures, the sandy soils turn into a solid mass. This grout is so strong that it is often used to solidify soil supporting buildings with large excavation pits right next to them. Grouts such as AP Soil 600 are the only option in some situations in which helical piers, push pile piers, or driven sheet piles cannot be used. AP Soil 600 is also installed in confined space situations where a non-invasive procedure is needed.

Installation is fairly straightforward. Typically injection tubing rods will be driven down to the depth required by the situation, with the rods spaced apart about every 18 inches. A small amount of catalyst is added to AP Soil 600 as it is slowly pumped into the sandy soils underneath. (The ideal pump system for this procedure is Alchemy-Spetec's PolyShark.) A gallon of product is slowly injected into the sandy soils for every foot of depth. Typically a small crew of two or three is all that is needed.

Once injected, the chemical grout will cure within 24 hours, solidifying the sandy soils and fortifying support for the structure's foundation. 

Want more information on stabilizing soil with polyurethane?

When an old brick retaining wall in downtown Greenville collapsed and crushed three cars, Wurster Engineering and Construction was called in to stabilize the embankment and install a new wall system. Based out of Greenville, SC, Wurster is a geotechnical engineering and construction firm that specializes in soil and embankment stabilization. The project would require removal of the remaining brick wall, soil nailing the embankment, installing a shotcrete wall, and then tying in a new brick wall to the stabilized embankment.

However, one problem remained. There was one area where there was a portion of the brick wall that needed removal, but the temporary concrete retaining wall to protect the property had been poured on a bed of gravel that was being held in place by the remaining brick. The gravel under the temporary wall footing was contained by the remaining brick, which when removed would cause all of the gravel to run out. This section was about 30-35’ long, 2’ high, and 4-5’ deep from the face of the wall to the back.

Powerful Polymer

In order to solve this issue, Wurster Engineering and Construction selected AP Fill 720 to permeate the gravel and hold it in place while the brick was removed. This polyurethane resin was the ideal choice because of its ability to thoroughly permeate the gravel, lock it all together, and then cure to a high compressive strength. With the gravel locked in place, Wurster Engineering and Construction was able to install supplemental support jacks under the temporary retaining wall. After the jacks were in place, they were able to install the soil nails followed by the shotcrete.

Painless Procedure

Approximately 50 gallons of AP Fill 720 were used to build this solidified wall of gravel behind the remaining brick wall. Injection probes were spaced 18” apart to ensure proper permeation and coverage needed to create one solid mass. The crew came in at a steep 20 to 30-degree angle behind the brick and put in about 2 gallons of polyurethane per probe, with 5% catalyst mixed in. The crew then installed more probes at a shallow 60-degree angle in the areas that needed further permeation and coverage. These extra placements of approximately 2 gallons per probe were essential to keeping the gravel in place from side to side and front to back. This entire process took one day to complete with a small crew of three people.

Rapid Result

The day after grouting, the site work demolition subcontractor chiseled off the remaining brick from the solidified AP Fill 720 gravel wall - and the project was determined to be a complete success. The entire job was finished quickly with minimal mobilization costs. We appreciate our friends at Wurster Engineering and Construction for trusting Alchemy-Spetec’s material and consultation for geotechnical projects such as this one.

Want more information about soil stabilization?

One of the most common questions I get about leak seal grout is along the lines of "Can I do this or that? Will it work?". I get this type of question regularly because every job is very unique and there is no one precise grouting procedure that fits everything. Let me introduce you to a term I love to use: exploratory grouting. This is the phase in which you are trying various methods until you find one that works for your particular application. While this just sounds like guesswork, it is very far from that.

So, I have come up with a short three-item list of the things you should not do while chemical grouting with urethanes:

1. Do not eat the grout!
2. Do not get the grout in your eyes!
3. Do not add water to the grout before pumping it. (Actually, there are rare times you do this.)

If you do not break those three rules, your work falls under exploratory grouting. We have a standardized leak seal crack injection procedure that will maximize your result (in a laboratory setting). But concrete restoration does not happen in a laboratory. Start with the procedure, but understand that the procedure is written for the spirit of what we are trying to accomplish. It is not written in stone (as long as you're following the three rules I have listed above).

Pro tip: Number one, do not eat the grout, seems like a no-brainer but it exists because we had a call from someone saying, "My worker ate your grout". 

In summation, remedial waterproofing is often an explorative process and can require on-the-fly adjustments. Setting expectations, maintaining open communication with all involved parties, and attention to detail are essential to making the waterproofing process efficient and successful. Here at Alchemy-Spetec, we have a wealth of experience navigating all types of waterproofing projects. We look forward to assisting you with your specific needs.

Want more information on leak seal products and equipment?

New year's message from Alchemy-Spetec Co-Owner and President Stephen C. Barton. (Stephen has been at the forefront of the concrete repair industry for over 30 years. Running leak seal crews in his teens, developing breakthrough polyurethane technology in his twenties, and helping grow the market ever since; Mr. Barton has been a leader in the field for most of his life.)

At the end of every year, I tell my team the same thing. “We have to reinvent ourselves. What got us to this point won’t get us where we want to go.” Every year we do just that. However, 2021 was special. We had to reinvent ourselves just about every month.

I won’t waste your time by repeating the phrase “supply chain issues”. I will say this: our team worked exhaustively to scour the earth for raw materials, reformulate our products, and finally manufacture and test the new formulations. In the end, we did everything in our power to live up to our entire reason for being – to serve our customers.

We learned more in the last year than we have since the inception of the business. We have more raw material options, formulations, and test data than ever before. These lessons learned will help us serve our customers more effectively than ever in 2022.

A lot of people are looking forward to putting 2021 in the rear-view mirror. Personally, I’m going to miss the challenges from last year that forced us to learn and grow. However, I’m sure 2022 will present some of the same issues and some unexpected new ones. I say, “Bring it on!” What doesn’t kill you makes you stronger.

Finally, I would like to say “Thank you” to all our customers who patiently waited for material to show up and endured the sticker shock of rapid inflation. Our team will be there for you again this year. Happy New Year! Now, let’s get to work…

Want more information on Alchemy-Spetec products?

It has become an Alchemy-Spetec holiday tradition to re-post this safety blog I wrote a few years ago.  Merry Christmas and Happy New Year!  (Andy Powell - Alchemy-Spetec Southeast Regional Manager.)

This time of year, most people will spend a little extra time with their loved ones.  It is also a time to reflect on the loved ones we miss that are no longer with us.  Like most of us, I know people who have either been lost or have suffered through a loss.  In those cases, there was nothing that could have been done to stop it.  However, there are things that we can do to guard against job-related safety hazards.

I've been fortunate enough to spend time in an OSHA safety training class.  It was required in order to be present supervising a project at a chemical facility.  Signing in at 6 AM, I’ll admit I was not looking forward to spending all day there.  By the end of the day, I was glad that I went.

In an intro video, the narrator said that every morning when you kiss your loved one goodbye before you go to work, keep in mind that someone, somewhere will not come home from work that day.  Workplace accidents are almost entirely preventable.  Investigations typically find the cause quite easily. 

The class I attended contained a dozen or so modules, each one with a video case study followed by the teaching.  Every case study module covered a different accident where people didn’t come home from work that day.  All of them could have been prevented.  I learned about fire, electrical and chemical safety; as well as confined space, ladders, scaffolds, and working in trenches.  I have worked in the construction industry since my teenage years, so it was sobering to look back and think about some of the close calls I had.

If you're a contractor or industry-related business owner looking for a good investment, send your employees to one of these classes.  It’s an excellent opportunity for them to learn safety principles that can protect you, your other employees, and your business from being lost.  It’s a gift that will keep on giving.  You don’t need Christmas as a reason to do this, but in the spirit of the season, you may want to make it the reason.  

Click here to find an OSHA safety class near you.

Merry Christmas and Happy New Year!

Do you know that leak that returns every year no matter how much hydraulic cement you put on it? Why not make this next time the last time you have to mess with it? Polyurethane grouts have some unique properties that allow them to do things concrete cannot. One of the most glaring is its flexibility.

I like to ask the question, "What is the difference between a joint and a crack?" A joint was engineered by humans while mother nature adds her cracks where the engineer did not see the need for one. They allow the concrete the ability to flex a bit as needed. These cracks can be caused by temperature changes, loading, and unloading, or even a difference in the coefficient of expansion of dissimilar materials, like a metal pipe in a concrete wall.

So, as you pick up that bucket of hydraulic cement, ask yourself, "Is this a dynamic leak? Is movement the issue at hand?" More often than not, movement is the issue and the solution is a flexible polyurethane grout. Spetec PUR GT500 and Spetec PUR F400 are two of the main Alchemy-Spetec grouts used in parking garages, elevator pits, and such. Spetec PUR GT380 is the main grout when it comes to sewers, wet wells, and the like. All of these grouts are highly flexible, NSF 61 certified for contact with drinking water, and allow the concrete to move without allowing it to leak.

Another misconception is that a repair material needs to be dry to effectively waterproof a structure. With polyurethanes that is completely wrong. We want and require water present when injecting the urethane grouts.

So, in summary, the best practice is to quit using hydraulic cement in situations where it will fail because of movement. Instead, waterproof once and effectively with a flexible polyurethane grout and be done with it.

Want more information on leak seal products and equipment?

Polyurethane foam was first discovered in 1937 by Dr. Otto Bayer who lived in Leverkusen, Germany. Bayer was a German chemist and was the head of the research group that discovered this new material. His fundamental idea of combining small volumes of chemical substances together to react into a dry foam material was viewed to be an impossibility. But after many trials and difficulties, Bayer eventually succeeded in synthesizing the first polyurethane foam.

Polyurethane was initially used as a cheap replacement for rubber. Widespread use began in World War II when many other materials became scarce. Polyurethane use quickly spread as a key component in many products, from specialized paper to protective military garments to gloss finishes and protective coatings.

In the 1950s, many companies such as DuPont, BASF, Dow, and Union Carbide started producing polyurethane for an even wider variety of applications including adhesives, insulation, and foam upholstery cushions. By the 1960s, polyurethane began being used for grouting purposes as we know it today. Here’s a brief snapshot of the history of polyurethane grouting:

• The 3M Company in the United States and Takanaka in Japan both introduced polyurethane grouts in the 1960s.
• 3M’s product was called Elastomeric Sewer Grouting Compound. As the name indicates, it was intended for use in underground utilities.
• Takanaka’s product was called Takanaka Aqua-Reactive Chemical Soil Stabilizer (TACSS). As the name indicates, it was intended for use in soil stabilization projects.
• In the early 1980s, DeNeef obtained the rights to TACSS and began distributing polyurethane grout worldwide. By the mid-1980s, there were almost a dozen manufacturers of polyurethane grouts.

Alchemy-Spetec CEO Stephen C. Barton started his career pumping 3M 5600 to seal cracks in the Atlanta subway system back in 1985. He was amazed at what it could do back then, and we're all still amazed at what our products do today. Despite still being specified in outdated documents, 3M exited the business many years ago and no longer manufactures the grout. In the last few decades, polyurethane grouting has become a widely accepted method for sealing leaks, stabilizing soil, and lifting slabs.

Want more information on leak seal products and equipment?