Curtain wall grouting is a method to create a waterproof barrier around the perimeter of a below grade structure. It involves pumping a hydrophobic grout through probe pipes driven down from the surface. Because water in the soil will activate the grout, this procedure should be done when the soil is wet. You will need Prime-Flex 910 or Prime-Flex 920, threaded 3/8", ½" or ¾" pipe, quick connect fittings, soil probes (3/8" or ¾") or expendable drive points (1/2" or ¾"), a single component pump, and equipment to drive pipes into the ground and to pull them out.
As close to the wall as possible, drive a pipe tipped with a soil probe or expendable drive point to the desired depth (typically eight inches below the foundation or footing). Avoid allowing the pipe to wallow in the hole. When the pipe has reached the desired depth, pour water around the probe to consolidate the soil tightly against the pipe.
Attach a "quick connect" fitting to the end of the pipe and attach the hose from the grout pump to the soil probe.
If an expendable drive point was used, pull the probe pipe up approximately 2-3 inches to open the end of the pipe.
Mix Prime Flex 910 or 920 with the proper amount of catalyst (see data sheet for more information). Because of its lower viscosity, Prime-Flex 910 works best in compact soils—the higher viscosity Prime Flex 920 works best in sandy soils.
Begin injecting grout. If it appears that most of the grout is traveling up alongside the pipe immediately when pumping is started, stop pumping, wait approximately three to five minutes and then resume pumping. This will allow the grout that was initially pumped to set up and seal the area around the probe pipe.
After pumping approximately ½ gallon of grout, use a pipe jack or manually pull the pipe upward 12 to 18" and inject again. Continue this process until the end of the pipe is two feet from the surface.
Move the probe to the next injection point (approximately two feet) and repeat the process. Continue around the perimeter of the structure.
