# 5 Steps to Polyurethane Foam Injection (From Drill Holes to Cure) > Maybe you're in the Russian Mafia or just a cool guy still kickin it in a bitchin' tracksuit and gold chain like it's the 90's, polyester is sexy. _Brian Dalinghaus ยท 2021-04-26_ --- Maybe you're in the Russian Mafia or just a cool guy still kickin it in a bitchin' tracksuit and gold chain like it's the 90's, polyester is _sexy_. Okay, so my wife and kids don't really agree; but here at Dalinghaus Foundation Repair, we believe _poly_ urethane is just as sexy as _poly_ ester. Polyurethane expands, it supports, it's flame-retardant and water-resistant, what's not to love. Okay, before you accuse me of _Pollyannaism,_ polyurethane really does miracles. Check out our exhaustive [Ultimate Guide To Foundation Repair](/foundation-repair/). In this article, we are going to discuss: - What is [[solution:foundation-repair/polyurethane-foam-injection|Polyurethane Foam]]? - Construction Applications - The 5 Steps of Polyurethane Foam Application ## What Is Polyurethane Foam? [[solution:foundation-repair/polyurethane-foam-injection|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 is a chemical compound that is implemented in liquid form before it expands into a solid, incredibly strong foam. Due to its initial liquid form, polyurethane permeates perfectly into cramped, difficult-to-reach spaces, such as void under sidewalks, patios, or **[foundations](/foundation-repair/)**. Polyurethane is environmentally inert and poses no danger to the environment. Here at Dalinghaus, we use AP LIFT 430, which is certified by Truesdail Labs to NSF/ANSI 61-5 ( _approved for contact with drinking water_). This is where polyurethane shines brightest. Polyurethane is a [[solution:concrete-leveling/mudjacking|considerably lighter alternative to Mudjacking]] (utilizing cement to reinforce, raise a previously settled structure). Also, unlike Mudjacking, Polyurethane _does not_ rely on the pressure of installation to lift up the slab, it relies on the _expanding power_(rather than the application force) to get the job done. This helps make it a cleaner, less invasive process in addition to the smaller installation sites. Mudjacking holes can be **_2 to 2.5 inches_** in diameter as opposed to **_5/8ths_** inch for poly. Polyurethane is so safe it is utilized in pacemakers. In addition, its cure time is considerably faster than Mudjacking, which can take up to **_28 days to cure_**. ## Polyurethane Construction Applications Polyurethane is used for a variety of applications. - ### Repair Cracked Concrete Slabs - ### Repair Settling/Sinking Concrete Slabs - ### Repair Settling/Sinking Foundations - ### Repair Void Fill - ### Permeate and Densify Soil ## Quick Characteristics of Polyurethane - Polyurethane is waterproof, water retardant, and non-water-soluble making it the perfect candidate for underground application in any climate - Polyurethane **_does not_** chemically react with moisture or soil - Polyurethane **_does not_** leak adverse chemicals into the substrate and is inert, environmentally neutral and does not contribute to water contamination - Polyurethane is adaptable across a wide variety of applications. It can easily withstand various temperatures, weather conditions, and soils. - Polyurethane is relatively noninvasive (particularly when compared to **Mudjacking**) While polyurethane has various applications, the installation process is pretty much the same across the board. Our 5-step process is applicable across the different implementations of polyurethane deep injection. ## Steps to Polyurethane Lifting - Drill holes - Application gun - Void Fill - Patch Drill Holes - Clean up and Cure ### Drill Holes Holes are punctured into the slab via a **_5/8th_** drill bit in a grid pattern. These holes are implemented **_18 to 24_** inches apart depending on the size of the void/affected area and soil conditions. The resulting hole is about the size of a **_nickel_**. The void is then probed for depth with a long bit or rebar pole. ### Application Gun It is important to note that polyurethanes are formed when a polyol (a type of alcohol containing multiple hydroxyl groups) reacts with a diisocyanate or polymeric isocyanate. This is just a fancy way of saying: _it takes two to tango._ The two separate chemicals mix at the nozzle of the gun, instigating a chemical reaction as the slurry is ejected via pneumatic fluid control. The chemicals **e x p a n d** very quickly, filling every nook and cranny with ease, providing support. We can regulate the reaction/rise time by controlling the liquid temperature and altering the chemical makeup. For example, deeper applications we can finess to delay expansion by over sixty seconds. Shallow injection sites can be filled in **_5 seconds_**. It all depends on the situation and is a case by case basis. ### Void Fill Polyurethane is for soil what chocolate cake is to the soul, an attempt to fill a void. As the polyurethane expands it compresses and densifies the soils, filling any voids or fissures. We go until there's a little bit of lift on the slab, which indicates there's enough pressure. The foam compacts and stabilizes the surrounding soil, providing support. ### Patch The holes are then patched with mud to match the original concrete. ### Clean up and Cure Then, all that's left is to clean up and wait for the new concrete to cure. And it looks like we were never there. ## Polyshore If you enjoyed this article, read more of our [**blog**](/blog/). You have now witnessed the full strength of street knowledge when it comes to polyurethane. *(Okay, so, the link below is actually for a free evaluation if you live in [Southern California](/service-area/) or [Central Arizona](/service-area/), which is actually just as exciting) ## Schedule a Free Evaluation Foundation movement is easier to judge in person than from a photo. [Schedule a free evaluation](/contact-us/) and a Dalinghaus specialist will walk the property with you and explain what the evidence shows.