Repairing of ultra fine cracks
. Repairing these types of cracks can be a challenge and are the most difficult to repair and require time and patience. In basement foundations some of these cracks can be found usually off the corners of basement windows or any 90° hole or angle in the concrete, these types of cracks me leak from time to time but are too small to inject polyurethane into. Polyurethane may start to expand before it has had time to completely penetrate through the wall one method would be to install Packers and use polyurethane under high pressure, this can be somewhat destructive to the concrete as injection holes would need to be drilled and the end results still may not be that effective. A very effective method has been to use ultra low viscosity epoxies that either are gravity fed or injected under pressure, this requires the use of a very slow curing epoxy to accomplish this method.
Some example methods listed below:
is typically done by sealing up both sides of the concrete wall and allowing for one spot near the top for low-pressure injection port to be installed in epoxy injected over a 2-4 hour period to allow the epoxy via gravity to drain into the smallest areas of the cracks.
low-pressure injection ports are installed along the crack typically 4 to 6 inches apart and a slow setting ultra low viscosity epoxy is injected using and pneumatic injection tool or a spring-loaded Jake tool starting at the bottom port. This process may take from minutes to a half hour per port to inject under low constant pressure of the epoxy to push it through the wall to the next port the typical pressure would be 30 to 40 pounds PSI.
Auto Injector system
Auto injectors are small elastic loaded syringes that maintained the pressure between 30 to 40 PSI the difference is that each auto injector is filled up with epoxy and installed on the ports one at a time or in groups and loaded with pressure. Auto injectors have the advantage that they can be left unattended while you do other work and simply return regularly to refill the auto injectors if necessary. This system is by far the simplest for applicators that have not had experience injecting low viscosity products into walls as over pressuring him injection can cause surface paste to blow off and created new leak. Auto injectors cannot be used with fast setting epoxies as the thermal characteristics of the epoxy may generate too much heat and actually melt the auto injector, auto injectors can be used with our ULV epoxy and all of our polyurethanes.
It must be noted that in all of these methods care must be taken to seal off any leaks that might develop as you do want to keep the epoxy in the wall before it cures, some epoxies can take up to four days to cure but even some of our slowest epoxies gel in at least 12 hours. Sealing leaks that develop can be done using some epoxy paste but for better results use a 5 min. epoxy or 455 fast setting epoxy.