Frequently Asked Questions

What is the complete procedure for injecting MC-Injekt 2700 HV into an active water-leaking crack in a basement concrete wall using MC-Packer injection equipment, and how many packers are needed?

Pressure injection of MC-Injekt 2700 HV for active water leak sealing is a specialist technique that requires proper packer installation, a suitable single-component PU injection pump, and understanding of the injection procedure. The complete procedure is as follows. Step 1 — Identify and map the crack. Mark the full length and extent of the leaking crack on the wall surface. Note the width at various points (typically with a crack microscope or magnifying glass — MC-Injekt 2700 HV can be injected into cracks from 0.1 mm width). Check for multiple parallel cracks or a crack network — each separate crack requires its own injection sequence. Step 2 — Install injection packers. Drill packer holes along the crack at a 45-degree angle, angled to intersect the crack plane approximately 50 mm behind the concrete face. For a standard 200 mm thick basement wall, drill holes at 45 degrees from the inside face to hit the crack plane at approximately 100 mm depth (mid-wall). Packer spacing: typically equal to the wall thickness for standard cracks (200 mm packer spacing for a 200 mm wall) — reduce to 100 to 150 mm spacing for narrow cracks or high-flow conditions. Standard packer size for 10 mm diameter holes — install mechanical or rubber-expansion MC-Packers into each hole and torque to seal. Step 3 — Flush with water. Using the injection pump, flush clean water through each packer in sequence to clean the crack channel and confirm connectivity between adjacent packers (water flowing from the adjacent packer confirms the crack is open between the two). Note which packers are connected. Step 4 — Prepare MC-Injekt 2700 HV. If using foam retarder to reduce expansion ratio (recommended for injection into narrow cracks less than 0.5 mm width to prevent excessive pressure build-up from rapid expansion), add MC-Injekt Retarder to the resin in the drum at the specified ratio (typically 2 to 5 percent by weight) and stir. Do not heat the resin — this accelerates reaction and reduces working time. Step 5 — Inject resin. Starting from the lowest packer (for vertical cracks, start from the bottom to prevent gravity-fed water from diluting the resin above the injection point), connect the injection pump hose to the first packer. Pump MC-Injekt 2700 HV slowly at low pressure (typically 3 to 5 bar for thin cracks, up to 10 to 15 bar for tight, high-pressure situations). Continue pumping until resin flows from the adjacent packer — then move to that packer and inject, leaving the previous packer open. Continue in this sequence along the crack. For active leaks with flowing water, inject rapidly until foam formation and pressure rise indicates the crack is filled, then hold pressure for 1 to 2 minutes before releasing. Step 6 — Post-injection. Allow the injected resin to cure for a minimum of 24 hours before assessing leak stoppage. If any residual seepage remains after 24 hours, re-inject the affected section with a second injection of MC-Injekt 2700 HV. Remove packers after 24 hours by breaking off at the wall face and filling the packer holes with cement mortar or Dr. Fixit Speed Watergrip. For long-term waterproofing, apply a cementitious waterproofing coating (such as MC-Bauchemie Nafuflex or MC-Bauchemie Nafucryl) over the entire basement wall inner face after leak injection to provide a backup waterproofing membrane over the injection-treated crack network.