This post is part of the Alchemy-Spetec Contractor Lens series, featuring views, news & case studies written by our customers. This article was written by Brian Dalinghaus of Dalinghaus Construction. 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!

Why Do Concrete Slabs Become Uneven?

Concrete slabs such as sidewalks, driveways, and patios, usually become uneven for one of the following reasons:

• Expansive soil – Expansive soil is clay-rich and for this reason expands as it soaks up moisture, and then shrinks as it loses moisture and dries out. This swelling/shrinking – which can be caused by drought/non-drought periods – causes movement in the soil under the slab, and will often cause a slab to become uneven over time.
• Erosion under the slab – Some types of soil are prone to erosion and if there’s poor drainage under the slab, this could cause voids to form and an uneven slab eventually.
• Soil not tamped down – Soil always needs to be properly compacted before anything gets placed or built on top of it, including concrete slabs. If this isn’t done, the slab could settle into the soil and end up uneven.
• Tree roots – We’ve all seen examples of tree roots pushing up on a slab and causing it to become unlevel.
• Dead leaves decaying leave voids – Leaves and other organic matter should be removed from the soil before a concrete slab is poured. If this isn’t done, voids could form under the slab. If the slab sinks into the voids, it will become uneven.

Uneven Concrete Slab Repairs Using Polyurethane Foam Injection

Fortunately, an uneven concrete slab can be repaired (i.e, leveled) in just a few hours using polyurethane foam injection, a waterproof material that’s injected under the slab in order to level it. Polyurethane foam injection can lift and level sidewalks, driveways, patios, pool decks, and more.

The general polyurethane foam injection procedure to perform concrete slab repairs is as follows:

• Dime-sized holes are drilled into the affected slab.
• A nozzle is inserted through the holes and the polyurethane foam is injected under the slab.
• The foam immediately begins to expand, fill any voids, and raise the slab.
• The holes are patched using a compound that matches the color of the concrete.
• Fifteen minutes after the repair is complete, the slab is ready for use.

Is Polyurethane Foam Better Than Mudjacking?

Yes, we believe polyurethane foam injection is better than mudjacking. Mudjacking is an older method for leveling an uneven concrete slab. Today, most concrete leveling jobs are done using polyurethane foam injection for the following reasons:

• The mudjacking slurry used to raise the slab is heavy because it contains cement, sand, soil, etc. Because of this, it has the potential to make the problem even worse because the slab might have become uneven due to weak soil that is unable to support it. If so, adding more weight to the soil in the form of a cement slurry isn’t going to help.
• The mudjacking slurry is prone to erosion if there’s poor drainage under the slab.
• The holes used to inject the mudjacking slurry under the slab are at least 2 inches wide. Compare this to the dime-sized holes used with polyurethane foam injection.
• Mudjacking is a messy process that takes 2-3 to dry and harden. This means downtime.

Yes, mudjacking is still being done today. However, we view it as a temporary fix, at best.

Are Concrete Slab Repairs Better Than Replacing The Slab?

Unless the concrete slab is severely damaged, yes, lifting the slab via polyurethane foam injection is better than digging up and replacing the slab. Concrete leveling using polyurethane foam is a quick procedure taking usually no more than a few hours and then the slab is ready for use. Pouring a new slab and then waiting for it to dry and harden takes time. Replacing a slab is also more expensive. Therefore, severely damaged slabs are typically the only cases that are not a good fit for leveling with polyurethane.

How Much Do Uneven Concrete Slab Repairs Cost?

The cost to fix an uneven concrete slab using polyurethane foam injection depends on where you live and the size of the affected area (this determines how much lifting foam is needed).

How To Help Prevent Concrete Slabs From Becoming Uneven

You can help prevent a concrete slab – such as a sidewalk or driveway – from becoming uneven, by doing the following:

• Make sure the soil is adequately tamped down before the slab gets poured on top of it.
• Ensure that any organic material (such as leaves) is removed from the soil before the slab gets poured.
• Make sure there’s good drainage under and around the slab.
• Keep trees with invasive root systems away from the slab.

If you have an uneven concrete slab that needs to be lifted and leveled (and you’re in the Dalinghaus Southern California and Arizona service area) click here to contact Dalinghaus today and schedule an evaluation.

Want more information on leveling concrete slabs?

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, provides an overview of polyurethane concrete repair material. 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!

Perhaps a foundation repair contractor has suggested polyurethane foam for deep injection, void fill, or slab lifting/leveling, but you’re not so sure about pumping “plastic” into the earth or underneath your home. You’re probably wondering: is polyurethane environmentally friendly? Is it effective?

If you’re concerned about the use of polyurethane for foundation repair and soil densification or just want to know more general information about PU, this article is for you.

Dalinghaus Construction Inc. has been in the foundation repair game since 2015. We have over 100 years of combined foundation repair experience and have serviced thousands of foundations in Southern California and Arizona via polyurethane-related repairs. We know everything there is to know about polyurethane and we’re here to share.

In this article, you will learn the definition of polyurethane, its history, many general uses, and how polyurethane foam is utilized in foundation repair.

What is Polyurethane?

Before you pump gallons of polyurethane foam underneath your home or into the soil around your property, you probably want to know what exactly it is.

Polyurethane Definition

Polyurethane is a synthetic resin compound comprised of carbamate/urethane groups linked to polymer units, often abbreviated as PU or PUR. In other words, polyurethane is a combination of chemicals/compounds that react to create a plastic-like substance. As a solid, polyurethane has an open-cellular structure – which is a foam.

Polyurethane foam, utilized for many purposes including insulation, sound-proofing, and foundation repair, is created by the chemical reaction of Diisocyanates and polyols (both of which are derived from organic crude oil). Because polyurethane is comprised of organic material, it is environmentally friendly and does not contribute to an increased eco-footprint.

Polyurethane is not a plastic. Technically, the elongated flexible polymer molecules that make up thermoset polyurethanes categorize this material as an elastomer (a natural or synthetic polymer having elastic properties, e.g., rubber).

Polyurethane foam is a safe, eco-friendly option to densify weak, non-load-bearing soil, void fill beneath your foundation following a lift/stabilization and relevel slabs.

History of Polyurethane

Polyurethane was invented in 1937 by the renowned German Professor Dr. Otto Bayer. Dr. Otto Bayer was an industrial chemist and worked for IG Farben – spearheading the research team that discovered polyaddition (the key to synthesis for polyurethanes by combining polyol and polyisocyanate).

Polyurethane first enjoyed widespread use in World War II as a rubber substitute. Polyurethane was utilized as airplane finishes, various coatings, and to create flame-retardant clothing. By the 1950s, Polyurethane was utilized for many different applications: couch cushion foam, rigid foams, elastomers, and adhesives.

Today, polyurethane is utilized for a wide variety of applications: mattresses, shoe soles, car seats, insulation, and even pacemakers. Polyurethane is a “behind the scenes” product, often hidden behind a layer of fabric, plastic, or other encasing material.

Due to its prevalence, in everything from car seats to pacemakers, it’s truly difficult to grasp the full scope and impact of polyurethane in everyday life – however, its importance in the foundation repair game is easy to explain.

Polyurethane and Foundation Repair

The foundation repair industry uses polyurethane foam primarily for soil densification, void fill, and lifting/leveling slabs back into place. 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.

The polyurethane foam is installed via an application gun: the polyols (a type of alcohol, containing multiple hydroxyl groups) and diisocyanate/polymeric isocyanate are pumped separately, but simultaneously. The chemicals combine and react after exiting the application gun.

The foam then expands, filling the void, densifying the soil, or lifting the slab back into place. In short, polyurethane has incredible expansive properties, allowing it to fill voids evenly and with ease – providing strength and support to the affected structure.

Here at Dalinghaus Construction Inc., we use Alchemy-Spetec's AP Lift 430 (which has been certified by Truesdail Labs to NSF/ANSI 61-5 – meaning it’s approved for contact with drinking water).

AP Lift 430 is:

• Waterproof (Hydrophobic)
• Noninvasive (Install Process is More Efficient and Replacing Concrete)
• Nonpolluting (NSF Approved for Contact with Potable Water)

In addition, AP Lift 430 weighs approximately 3 pounds per cubic foot and reaches 90% compression strength in only 15 minutes. And, finally, polyurethane can hold 7,200 pounds per square foot. In short, polyurethane is a fantastic solution for foundation repair and hillside stabilization needs.

Polyurethane Foam is Safe, Effective, and Environmentally Friendly

In this article, you learned the definition of polyurethane, how it was invited by Dr. Otto Bayer, the wide spectrum of uses, and how polyurethane foam is utilized in foundation repair and construction. You also learned that polyurethane is a safe and effective product. Dalinghaus Construction has helped hundreds of homeowners and offers an array of services, including carbon fiber crack repair, steel pier underpinning, and more. 

Click here if you live in Southern California or Arizona and would like to book a free foundation inspection.

Want more information on polyurethane repair products?

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?

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, contrasts polyurethane slab lifting vs mudjacking (lifting slabs with a mortar-based mixture of "mud" or "slurry"). 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!

Do you have a sinking slab that needs a lift? There are two primary lifting services in the construction industry capable of lifting, stabilizing, and leveling your foundation/flatwork: polyurethane injection and mudjacking.

If you read our blog, keep up with our Instagram, or watch our Youtube channel, then you’ve undoubtedly heard a lot about polyurethane…but not much about mudjacking. 

This is because we tend not to write extensively on services we do not provide – however, in this article, we are going to analyze the 3-key benefits of polyurethane slab lifting over mudjacking:

1. Lighter Weight
2. Smaller Hole Size for Application
3. Faster Cure Time 

What is Mudjacking?

Mudjacking is the lifting or leveling of a structure, driveway, or slab of concrete by pumping a mixture of slurry (with incredibly high pressure) underneath a sunken slab.

Polyurethane Weighs Less

Polyurethane weighs 2-4 pounds per cubic foot. Mud can weigh as much as 100 pounds per cubic foot. Weight is important because it can act as an anchor, sinking an already settling ship.

Polyurethane can help stabilize soil by adding rigidity – mudjacking simply packs on more weight. Yes, mudjacking is extremely effective at lifting settled flatwork and is attractive because of its relatively cheap cost, but it is not a long-term solution.

The mud will eventually settle into the expansive soil.

Polyurethane floats on expansive clays and only settles when the soil beneath it gives way. Polyurethane is lightweight, dense, and incredibly strong.

Polyurethane relies on the expansive pressure for the lift. Mudjacking relies on installation pressure.

Fun Facts with Brian – Polyurethane expands kind of like shaving cream after leaving a can, allowing it to fit perfectly into crooks and crannies as it balloons outward.   

Polyurethane Utilizes Smaller Application Holes

Polyurethane and Mudjacking follow the same three-step system: Drill, Pump, Patch.

The biggest difference in the system itself is the size of the application hole.  

Poly & Mudjacking’s Three Steps –

• Drill – Drill into the concrete (often in a grid pattern)
• Pump – Void fill the hole with a slurry application gun
• Patch – Patch holes and color code the concrete to match

The polyurethane injection site hole is only 3/8" to 5/8” (depending on the type of injection), whereas mudjacking injection holes are 2 to 3 inches.   

Unless you want your driveway looking like a Dalmatian, we suggest utilizing polyurethane. The patched injection sites are far less noticeable.

In addition, mudjacking can prove a bit of a mess, with excess slurry slurping out of cracks and crevices. The polyurethane foam, once dry, is easy to square off with a boxcutter.

Polyurethane Cures Faster Than Mud

Polyurethane cures quickly, solidifying up to 90% full strength in 15 minutes. In contrast, mudjacking slurry shot underneath the slab is never exposed to sunlight (thus taking a much longer time to cure).    

The truth is: slurry can take several days to a week to dry. And, fun fact about concrete, it never really fully cures.

Why Choose Polyurethane Injection? 

Polyurethane is lightweight, easy to install with little chance of a mess, and cures incredibly fast. Mudjacking, on the other hand, is not a permanent fix and can sink your flat-work.  

If you live in Southern California or Central Arizona and would like a FREE void fill inspection, click the link below -

Want more information on polyurethane slab lifting?

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, is an overview of warehouse floor repair 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!

You hide it well, but we know the truth – you’re obsessed with warehouse floors.

You eat, sleep, and breathe warehouse life: the melodic beeping of the forklift, the acrid welding haze that tastes like metal, and the unmitigated triple-digit heat because air-conditioning is for wussies. And don’t forget about your well-adjusted mechanic who swears so fluently it sounds like poetry while they blast AC/DC out of a busted ‘98 JVC stereo.

Welcome to #warehouselife.

Ok, so really, most people don’t give warehouse floors much thought. On occasion, you may have to sweep or mop, but that’s about the average extension of warehouse floor TLC. However, your forklift operators and warehouse crew may begrudge your lack of warehouse floor maintenance. Warehouse floors that are uneven, cracked, or sinking can create tripping hazards and other OSHA concerns.

Busted warehouse floors directly translate into a less efficient workspace, creating bumpy forklift track that can result in trouble moving loads around the sunken concrete. The truth is: if you take care of your warehouse floor, it will take care of you.

Causes Of Warehouse Floor Problems

There are several causes that may make repairs to the concrete warehouse floor necessary.

• Incorrect Curing
• Soil Erosion
• Insufficient Soil Preparation
• Shrinking and Expanding Soil

Voids can occur underneath the warehouse floor slab. Heavy equipment, like forklifts or electric pallet jacks, can cause the slabs to tilt and shift into uneven positions. This precarious situation can cause a forklift operator to lose a heavy load or get their equipment stuck.

Uneven floors jeopardize the safety of your warehouse crew and the safety of your product. In short, it can lead to serious injury and/or damage to equipment and materials.

Solutions For Uneven Warehouse Floors

Luckily, there is a solution to uneven warehouse floors. It’s imperative to protect your employees, equipment, and inventory by making sure the warehouse floors are even and stable.

Here at Dalinghaus Construction, Inc., we utilize Alchemy-Spectec or slab leveling to ensure that concrete slabs are level, secure, and strong.

During the Alchemy-Spectec process, polyurethane foam is injected through small holes underneath the slabs. The foam expands, filling the void under the slab and simultaneously lifting the slab back into place.

The polyurethane installation process allows us to move the slab within a tenth of an inch of the desired height. That is truly remarkable precision. The polyurethane foam is waterproof, environmentally inert, and won’t wash away.

• Repair Cracked Concrete Slabs
• Repair Settling/Sinking Concrete Slabs
• Repair Settling/Sinking Foundations
• Repair Void Fill
• Permeate and Densify Soil

Polyurethane cures quickly, solidifying up to 90% full strength in only 15 minutes. The polyurethane foam seals at the bottom of the warehouse floor slab, closing off any crack that may exist in the concrete.

If needed, a joint fill material is utilized to help prevent any serious gaps between slabs.

Once the warehouse floor has been leveled, this allows heavy equipment to run smoothly over the joints, considerably lessening the damage to wheels or edges of the concrete. These gaps allow the slabs to expand and contract without cracking or moving out of place.

The great news is the Alchemy-Spectec process does not need a lot of heavy, specialized equipment – meaning you won’t have to make a lot of room for us to work. Also, as mentioned above, polyurethane foam only takes 15 minutes to cure to 90%.

This directly translates into getting back to work ASAP. The Alchemy-Spectec process is less expensive and time-consuming than tearing up and replacing a concrete slab and will take care of any underlying problems that were causing the concrete to sink.

Make Your Warehouse Safer with Dalinghaus

The safety and efficiency of your employees (along with keeping your equipment and product in good shape) are invaluable. Dalinghaus Construction Inc. is here to help you by making sure your warehouse floors are strong, stable, and straight.

Our concrete lifting process provides long-lasting results, ensuring your warehouse floor is level and safe. With over 100 years of combined experience and 4.9 stars out of 299 reviews – we are here to ensure that you never settle.

If you live in SoCal or Arizona and would like a FREE foundation inspection, click the link below –

Want more information on warehouse floor repair?