Frequently Asked Questions

During the monsoon season in Ghaziabad, a developer reports that the basement retaining wall of a newly completed 8-floor residential tower has multiple active water jets and seeping cracks — what is the correct injection repair procedure for stopping the leaks using MC-Injekt 2K two-component PU resin, and how does the approach differ for fast-flowing water jets versus slow seepage zones?

Active basement water leaks in a newly constructed residential tower during the Delhi NCR monsoon — especially in Ghaziabad where the water table rises significantly during July and August and hydrostatic pressure can develop rapidly behind basement retaining walls that have inadequate external waterproofing or drainage — are an emergency situation requiring rapid and systematic intervention. The correct approach with MC-Injekt 2K two-component polyurethane injection resin is as follows, with differentiated treatment for fast-flowing jets versus slow seepage zones. Initial assessment and mapping: before starting any injection, map all leak locations on a sketch of the basement wall elevation — mark each leak point with numbered markers (chalk or marker pen) and classify each as fast jet (visible water stream with velocity), slow seep (wet surface with drip or trickle), or damp zone (moist but no visible flow). This classification drives the injection sequence and technique. Preparation for fast-flowing water jets: fast jets occur where a concentrated water path through the concrete — a crack, cold joint, or voided zone — carries significant hydrostatic pressure from the saturated soil outside the wall. For these locations, the first intervention is to install a temporary water stop using rapid-setting plug mortar (MC-Baudur 1 or a proprietary hydraulic cement) to reduce the flow to a seep before injection. Form a conical chase around the jet with a cold chisel and hammer, apply a ball of hydraulic cement mixed to a stiff paste, and hold it in place for 60 to 90 seconds until initial set stops the jet. If the jet cannot be stopped with hydraulic cement (flow too high, pressure too great), install a temporary drain tube (a 12 mm diameter rubber hose inserted through the hydraulic cement plug and sealed around with the cement, leaving the hose open to vent the water flow) to relieve pressure and allow the surrounding cement to set. Drill injection port holes: using a rotary-hammer drill, drill 12 to 14 mm diameter holes along the crack or seam at 45 degrees to the wall face (angling toward the crack within the wall cross-section) at 150 mm to 200 mm spacing for fast-flow zones, or at 200 to 300 mm spacing for slow seep zones. Drill to a depth of approximately two-thirds of the wall thickness (typically 100 to 150 mm for a 150 to 200 mm basement wall) to place the injection resin at the mid-section of the wall where the crack path is likely to be most concentrated. Hammer in steel or plastic injection packers (12 to 14 mm external diameter, matching the drill hole) and tighten the packer nut to create a seal between the packer and the drill hole wall. Injection procedure for slow seeps: connect the dual-component injection pump (loaded with Part A and Part B of MC-Injekt 2K in separate cylinders) with a static mixer nozzle to the packer using a flexible high-pressure hose. Begin injection at the lowest packer on the wall and inject slowly at 10 to 20 bar pressure, maintaining injection pressure while the resin travels through the crack network, reacts with the moisture in the crack, and expands to fill the void. Watch for resin emergence from adjacent packers — when resin (or reacted foam) appears at the next packer, that packer has been reached and injection at the current packer is complete. Close the current packer valve, move to the adjacent packer (the one where resin just emerged), and continue. Work from the bottom of the crack upward, or from the highest-pressure (wettest) point outward. For slow seep zones, this systematic packer-by-packer injection sequence reliably seals the seep path. Injection procedure for fast-flowing water jets (after temporary hydraulic cement plug is in place): inject MC-Injekt 2K at higher pressure (40 to 80 bar, using a high-pressure pneumatic or electric injection pump) through the packers adjacent to the plugged jet zone. The resin rapidly contacts the water remaining in the crack path, expands to 10 to 20 times its liquid volume, and forms a compressible foam barrier against the hydraulic cement plug. After curing (5 to 10 minutes), the hydraulic cement plug can be carefully removed (by drilling) and reinjected with MC-Injekt 2K directly — since the surrounding foam barrier has now reduced the flow, the direct injection into the former jet zone can be completed without the jet washing the resin away. After all injection is complete and the resin has fully cured (minimum 24 hours), remove the packers, grind the wall surface flat at packer locations, and apply a two-component cementitious waterproofing coating (MC-Protect KH 2 or equivalent) over the entire basement wall face as a secondary negative-side waterproofing layer to protect against any minor re-emergence of moisture at untreated points. Space Arc Engineering supplies MC-Injekt 2K, hydraulic cement, and the complete MC-Bauchemie injection and waterproofing system for basement and structural injection repair projects across Ghaziabad, Delhi NCR, Noida, and Uttar Pradesh, and provides on-site technical assistance for specialist injection programmes.