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PU Injection Grouting Contractor in Mumbai
PU injection waterproofing for leaking cracks, construction joints and honeycombed concrete.
PU injection waterproofing for leaking concrete
Mabani Infra is a PU injection grouting contractor in Mumbai. We seal active leaks through cracks, construction joints, honeycombed concrete and pipe penetrations in basements, lift pits, underground tanks, STP tanks and podium slabs.
Polyurethane (PU) resin is injected under pressure through packers drilled into the concrete. On contact with water the resin reacts and expands, filling the crack or void and blocking the path the water was taking. Because the treatment works from the accessible face of the structure, PU injection is often the practical answer for an existing building where the waterproofing on the outside cannot be reached.
Where we use PU injection grouting
- Leaking cracks in basement walls, raft slabs and retaining walls.
- Construction joints and cold joints that let water through.
- Honeycombed or poorly compacted concrete.
- Leaking lift pits and underground water tanks.
- Seepage around pipe sleeves and tie-rod holes.
- Leaks through podium slab soffits into basements below.
Method, not a membrane. PU injection grouting stops water at defined cracks and joints. Where water passes through a large area of the structure, injection is combined with a membrane or coating system, as described on our basement waterproofing page.
PU injection grouting procedure
- Survey the structure and mark every leaking crack, joint and damp patch.
- Select the resin system (water-reactive foam, or a flexible resin) to suit the water flow and the specification.
- Drill holes at an angle to intersect the crack and fix injection packers at the spacing given in the method statement.
- Flush the crack where specified.
- Inject resin from the lowest packer upward, moving along the crack as resin appears at the next packer.
- Repeat injection where seepage continues.
- Remove or cut packers, make good the drill holes and surface, and re-inspect for leakage.
Hydrophobic and hydrophilic PU resins
Hydrophobic PU resins react with water to form a rigid or semi-rigid closed-cell foam and are commonly used to cut off running water. Hydrophilic PU resins absorb water to form a flexible gel or foam and can suit joints with some movement. The resin is chosen against the manufacturer's current technical data sheet and the approved specification.
Representative images of each work stage.
PU injection grouting: frequently asked questions
What is PU injection grouting?
PU injection grouting is a leak-sealing method. Polyurethane resin is pumped through injection packers into a crack, joint or void in concrete, where it reacts and fills the water path. It is a repair method, not a surface membrane.
Can PU injection be done while water is actively leaking?
Yes. Water-reactive polyurethane resins are designed for wet and actively leaking cracks, which is why PU injection waterproofing is widely used in basements, lift pits and underground tanks. The resin type is selected for the water flow and the manufacturer's data sheet.
What is the difference between PU injection and epoxy injection?
PU injection is used to stop water. Epoxy injection is used to bond the two faces of a dry, non-moving crack where structural continuity matters. Where a crack may be structural, it is assessed first and treated as part of a structural repair.
Do tiles or finishes need to be removed?
Packers are drilled into the concrete along the crack, so the crack has to be accessible. Where tiles, plaster or other finishes cover the leaking area, they are usually opened locally first. We confirm this during the site inspection.
How long does PU injection last?
It depends on whether the crack is still moving, the resin used and the quality of drilling and injection. We do not quote a fixed life. Treated areas are re-inspected after injection, and further injection is carried out where seepage remains.
Tell us about your project
Send the structure, location and scope. For a site visit, include a preferred date. Inquiries go straight to our operations team at operations@mabani.in.