Damp cracks and leaks
Sealing cracks in concrete and underground structures and limiting water flow at active leaks. Contact with water initiates the resin reaction.
STRUCTURAL INJECTION
HydroGum
Polyurethane resin · one-component · water-reactive
| Base / system | Polyurethane (PU) · one-component (1K) |
|---|---|
| Viscosity | 370 ± 30 mPa·s at 23°C |
| Density | 1.12 g/cm³ at 23°C |
| Reaction with water | Requires contact with water; flexible, foamed filling |
| Start / end of reaction | 40 s / 2 min 30 s Resin : water = 1 : 1 by weight; conditions and working time ↓ |
| Volume increase | up to 4 times |
| Application temperature | Above +5°C — material, ambient and substrate |
| CE marking | CE marking indicated in the manufacturer's declaration of performance for concrete injection. |
Sealing damp cracks, concrete slab joints, sewer pipes and movement joints. Applications and limitations ↓
Technical data
Resin properties and parameters given in the technical instructions. A material test result is not a pump setting parameter.
| Viscosity at 23°C | 370 ± 30 mPa·s |
|---|---|
| Density at 23°C | 1.12 g/cm³ |
| Watertightness — EN 14068 | 2 × 10⁵ Pa (0.2 MPa) |
| Tensile strength — PN-ISO-37_2007P | 76.6 kPa |
| Elongation at break — PN-ISO-37_2007P | 33.3% |
| Compressive stress at 10% deformation — PN-EN 826:2013-07 | 20.2 kPa |
| Volume increase | up to 4 times |
| Colour | Light yellow |
- Storage
- In a dry place, +10 to +30°C according to the technical instructions
- Shelf life
- 12 months from manufacture in the original, unopened packaging. Shelf life decreases rapidly after opening.
Reaction with water versus pot life
The start time of 40 s and end time of 2 min 30 s refer to mixing resin with water at 1 : 1 by weight. The data sheet does not specify the test temperature. Temperature and the amount of water affect the reaction.
The 30 min at 20°C limit applies to the resin alone in the pump and hoses before contact with water. It is not the working time of a mixture downstream of the mixer. Follow the more frequent cleaning intervals stated in the application instructions.
Confirm application conditions →Applications and limitations
Selection begins with assessing water, the path of the gap and structural movement.
Slab joints, sewers and movement joints
The data sheet covers joints between concrete slabs, sewer pipes and movement joints. The magnitude and nature of displacement must be considered when selecting the solution.
Dry cracks — variant with water delivery
The instructions permit application with a two-component pump in a 1 : 1 system with water. HydroGum remains a one-component resin; the second stream is water. For application, deliver resin and water through separate circuits of a 2K pump at a 1 : 1 ratio by volume. The reaction time test of 40 s / 2 min 30 s uses a resin : water ratio of 1 : 1 by weight.
Space around penetrations
HydroGum may be selected to seal spaces around penetrations after substrate preparation and confinement of the outflow zone. Ensure controlled contact with water, correct distribution and assessment of joint movement. Check watertightness after injection under site conditions.
Capillary barrier and masonry saturation — conditional selection
HydroGum may be considered for a capillary barrier and sealing impregnation of masonry following individual selection and a trial. Confirm distribution, filling continuity, water access for the reaction and confined expansion. Selection depends on masonry structure and moisture; check watertightness after injection. Foaming alone does not confirm interruption of capillary transport.
Sealing through hoses — conditional selection
HydroGum may be considered for sealing through injection hoses after confirming compatibility with the specific hose system, its patency and the time required to distribute the material. Selection and trials must control water access, expansion and complete zone filling. This application does not declare that the hose can be reinjected.
Waterproofing curtain — conditional selection
HydroGum may be selected for a curtain outside the structure after assessing soil, voids and water flow. A trial must confirm distribution, continuity and watertightness of the zone. Ensure water access for the reaction and control expansion and material migration; volume increase alone does not determine curtain reach.
Flexibility does not define permissible movement joint displacement.
An elongation at break of 33,3% is not a declaration of permissible joint displacement. Similarly, foaming up to 4 times is not used to determine repair consumption. Perform a trial under the conditions of the task.
METHOD
Injection diagrams
The cross-section shows a borehole intersecting the crack, material delivery through a packer and observation of its passage to adjacent points.
1. Intersecting the crack
The borehole location follows from assessing the path of the gap, element thickness and selected angle.
2. Controlled delivery
Pressure is selected for the structure and crack. No single value is suitable for every task.
3. Observing passage
Outflow at the next point helps track the material path. Pressure alone does not confirm complete filling.
Preparation and application
For professional use. Material, substrate and ambient temperature must be above +5°C.
Assess water and prepare the substrate
Assess the structure. Remove loose fragments and contaminants that reduce adhesion. Distinguish between a damp crack, active flow and a dry crack.
Drill holes and install packers
Select boreholes for the path of the gap and clean them. The prepared crack surface may be closed with mortar CrackOn.5, according to the instructions.
Select the delivery method
The resin is supplied ready to use in a single-component system. For a dry crack, the data sheet specifies a two-component pump with separate water delivery. Do not treat this variant as a recommendation to mix water in the tank of a 1K pump.
Inject from the lowest point and observe
For a vertical crack, start at the bottom. Observe outflow at the next packer and move the injection point. Select pressure for the structure and crack size; the watertightness value in the table is not the injection pressure.
Clean and protect the equipment
The instructions specify cleaning with PI-CLEANER after application and during pauses exceeding 15 minutes, followed by maintenance with PI-SAVER. This threshold does not mean it is safe to leave a mixture with water in the system for that time; consider its much shorter reaction and the pump instructions.
In the resin + water variant, also clean the 2K system with PI-CLEANER before the material sets.
Material selection and preparation
Product documentation
Full technical requirements and safe working principles. Before use, check that the documents are current for the supplied batch.
Working with water-reactive resin
The product contains isocyanates. Use protection and ventilation according to the safety data sheet. Protect the packaging from moisture: contact with water may cause a reaction releasing CO₂ and increasing pressure in a closed container.
HydroGum technical support
Selection of the delivery method, reaction conditions and delivery documentation.