Polyurethane Repair FAQ
HOW DOES THE PROCESS WORK?
1. Penny size holes are strategically drilled in the affected area based on the location, area and scope of the repair.
2. A two part polyurethane mixture is mechanically injected through the hole utilizing carefully calibrated injection equipment. Underneath the concrete a chemical reaction occurs where the two components mix to create an expanding foam. The foam fills all voids and stabilizes loose and non-compacted soil while expanding to create the lift. Enough material is injected into the troubled areas until the desired height is achieved and the concrete has returned to its origin.
3. The holes are then filled with a high density cementious grout and finished to match the existing concrete. You won’t even know we were there!
WHAT ARE THE BENEFITS OF POLYURETHANE?
- Smaller and fewer holes are needed to complete job
- Hole repair almost unnoticeable
- Completely cured and ready for service within 15 minutes
- Strong, light weight and dense
- The foam will find a path to fill in all gaps and voided areas under concrete
- The foam is not weakened by moisture or chemicals found in soil
- The foam will retain its structure and strength reducing the possibility of new gaps or settlement
- The foam seeks out weak soils and voids during expansion, creating a strong and denser base
- Polyurethane foam is environmentally friendly. It is an inert material that is self contained and does not leach.
HOW DO I CHOOSE A REPAIR COMPANY?
There are several factors to consider when choosing a repair company. There are, however, a few factors that are more important than others. One, is the company you’re using properly licensed and insured in the jurisdiction where the work will be performed? Two, are the systems that they are using designed specifically for concrete raising and stabilization applications? Unfortunately, there are a few companies performing this type of work that are not using proper systems. Third, have you done your homework? There are several online contractor advocacy websites that provide free, unbiased reviews from customers that have used these companies. In some cases the repair process is not an inexpensive proposition and you want to make sure that you choose the best service company based on the information that’s available to you.
IS THIS LIKE THE STUFF THAT COMES OUT OF THE CAN?
This is probably our most commonly asked question and arguably the most important. The only similarity between the foams we use and what comes out of the can is that they are expanding foams. Other than that they have nothing in common. There are nearly a 1000 different types of expanding foams and every one serves a different function. The systems that we use are manufactured by North Carolina Foam, Inc, the first and only company to develop a chemically stable polymer specifically formulated for geotechnical applications. Liftech is one of only a few companies in the state of Colorado that is certified and authorized to use these systems. There are other companies across the front range that are using closed cell polyurethanes that are not designed for geotechnical applications and are therefore susceptible to failure. NOT ALL FOAMS ARE CREATED EQUAL!! Do your homework! Make sure to ask the company that you’ve considered hiring who manufactures their foam and if it is not an NCFI product you may want to reconsider! For more information on the polymers we use click here.
HOW MUCH DOES IT COST?
The cost depends largely on the amount of material that needs to be used to achieve the desired result. Generally speaking polyurethane concrete lifting costs half or less than replacement. We provide free onsite estimates and you can take advantage of a 10% discount off your project when you submit your project details online. To find out more about our digital quote promotion click here.
HOW LONG DOES THE CONCRETE REPAIR PROCESS TAKE?
With residential work the vast majority of projects can be completed in less than a day, usually in a few hours or less. With commercial or municipal projects, the duration depends on the scope.
IS IT SAFE FOR THE ENVIRONMENT?
The components used are manufactured using non-toxic and environmentally safe materials. Once the components are mixed, the polyurethane develops an outer skin, like a balloon, to contain the reactions process, which makes it completely inert. There are absolutely no environmental restrictions on our material.
IS THE PROCESS NOISY?
The equipment we use is permanently mounted on our trucks and trailers and the noise they generate is contained, for the most part, on the units. The injection gun that is used to inject the material under the concrete makes little to no noise.
WILL MY LANDSCAPING BE DISTURBED?
Our trucks are parked in the street or right of way and light weight, flexible hose is pulled across the hardscape and directly to the affected areas. At no time will any landscape be accessed or disturbed.
HOW LONG DOES IT LAST?
Because polyurethane cures as a solid structure it doesn’t have the same potential for fracture and failure as does a sandy slurry. Polyurethane is a completely inert, solid material that is impervious to water, chemicals, insects, rodents or erosion and as long as the substrate continues to perform the polyurethane will last indefinitely.
IS IT POSSIBLE FOR MY CONCRETE TO MOVE FOLLOWING THE REPAIR?
Absolutely! It can and more than likely it will, especially in exterior environments. Along the front Range we are dealing with highly volatile soil conditions. Most areas along the front range have soil with high concentrations of bentonite (clay). Bentonite is highly absorbent and will shrink and swell depending on it’s moisture content. Depending on the time of year soil can expand or contract depending on the level of moisture present. The concrete that is sitting on top of the soil is subject to that same movement. It’s important to know that the polymers that we inject do not fail. It is not uncommon for concrete to show signs of settlement up to as much as an inch in the summertime for repairs that were performed in spring. This is no cause for concern. There’s a very good chance that the concrete will return to its origin once moisture returns to the soil in the fall and winter. If it looks as though you’ve experienced some settlement a few months after the repair, especially in the summertime, do not be alarmed. Be patient and let’s wait to see what happens come fall winter.
HOW LONG BEFORE I CAN USE MY CONCRETE?
Polyurethane sets up in minutes. The material is fully cured and ready to return to service in 15 minutes. You can use your concrete again by the time we drive away!
IS IT POSSIBLE TO OVERLIFT?
With any concrete raising process there is always the possibility of over lifting, however it is far less likely with polyurethane. The process is very controlled and methodical. A few inches of lift can take several minutes. The process is monitored very carefully. Each injection takes only 10-15 seconds to fully expand. Injections are administered in 25-30 second intervals allowing time for maximum expansion. Once the desired amount of material is injected and the desired lift is achieved no more material is administered.
HOW DOES THE PROCESS WORK?
The polyurethane systems that are injected under the concrete and into the soil form solid structures that bond the soil to the concrete and are not susceptible to fracture or failure. There are, however, instances that can cause reoccuring failure even after the repairs have been performed. If the cracks and joint on the surface of the concrete are not properly sealed it can allow additional moisture to move through those open cracks and joints under the concrete and undermine the repair. It is very important to correct and maintain the grade or slope of the soils surrounding the repaired areas to allow moisture to move away from the area and not allow water to stand where it can ultimately settle in and affect soil at depth which could cause continued settlement. It is also very important to point out that at no time should any sprinkler or drip line systems be used in areas surrounding walkways. All added water sources should stay at least 5 feet away. Taking these necessary steps following the repair will ensure that the performance of the concrete will last a lifetime.