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Mountain Grout Flexible: A Technical Overview
Mountain Grout Flexible is a low-viscosity, hydrophobic polyurethane injection system that reacts with water to form a durable, closed-cell grout. Pumped as a single component with optional Accelerator “B”, it gives professional applicators precise control over gel and rise times to suit leak severity and temperature. The cured grout retains volume through wet/dry cycles, adheres tenaciously to concrete, and delivers a reliable, inert, non-toxic seal — ideal for remedial waterproofing in civil and building infrastructure.
30×
Expansion on reaction for effective void filling
Core Features & Specifications
- Hydrophobic polyurethane forms closed-cell grout that resists shrinkage through wet/dry cycles.
- Pumps as a single component; add Accelerator “B” to tailor reaction profile to site conditions.
- Low viscosity liquid (~500 mPa·s) promotes penetration into fine cracks and hairlines.
- Up to 30× volumetric expansion to chase water paths and fill voids efficiently.
- No VOCs, 100% solids; non-flammable with high flash point for safer handling.
- Cured properties: density ~64 kg/m³; elongation ~44% for dynamic service conditions.
- Reaction control: at 1.25% B, expansion starts ~50 s, completes ~4 min; at 2.5% B, starts ~15 s, completes ~65 s (at 25 °C).
- Designed for critical remedial tasks: manholes, stormwater, dams, tunnels, elevator pits, parking structures, and treatment plants.
The Mountain Grout Flexible Advantage
- Engineer confidence: stable, closed-cell structure delivers a permanent, inert seal under cyclic wetting.
- On-site control: dial in gel/rise times with Accelerator “B” to match leak severity and temperature.
- Productivity: single-component pumping reduces setup complexity and speeds mobilisation.
- Coverage certainty: 30× expansion tracks water pathways to seal beyond the visible crack.
- Safer handling profile: non-flammable, no VOCs, high flash point.
Proactive Troubleshooting
Scenario: Minimal water at the crack face
Potential Outcome: Incomplete reaction and insufficient rise in dry sections.
Adheseal Best Practice: Pre-wet the crack path (not flood) to ensure consistent contact water; select Accelerator “B” dosage to achieve reliable gel at site temperature.
Scenario: High-flow active leak washing out resin
Potential Outcome: Resin displacement before foaming, leaving leak pathways open.
Adheseal Best Practice: Increase Accelerator “B” to shorten start time, stage-inject from downstream ports, and reduce injection pressure to favour in-situ foaming and capture.
Scenario: Sparse port layout on thick concrete
Potential Outcome: Unfilled voids and intermittent sealing.
Adheseal Best Practice: Tighten port spacing based on element thickness and water path behaviour; inject until adjacent ports show material or flow reduction is observed.
Applications in Practice: Trade Scenarios
For Remedial Waterproofers (On-site Applicator): Stopping active leaks in basement cracks
The Professional's Challenge
Active water is displacing materials during injection. You need reliable gel and rise before washout while maintaining penetration into hairlines.
The Adheseal Solution: Engineered Certainty in Practice
Pump Mountain Grout Flexible as a single component and tune Accelerator “B” to 2.5% for rapid start (≈15 s) and completion (~65 s at 25 °C). Stage injections from downstream to upstream, keeping pressures modest so foaming locks the pathway.
Best Practice Note
Confirm pre-wetting on very dry sections. Continue until steady backflow or dampening appears at the next port.
For Asset Maintenance (Specifier/Engineer): Infiltration at manhole penetrations
The Professional's Challenge
Intermittent inflow and seasonal wet/dry cycling cause prior repairs to shrink and open up.
The Adheseal Solution: Engineered Certainty in Practice
Specify Mountain Grout Flexible for its hydrophobic chemistry and closed-cell structure that retains volume through cycles. Dose Accelerator “B” ~1.25% for controlled rise (start ~50 s, complete ~4 min at 25 °C) to ensure thorough grout development around the penetration.
Best Practice Note
Map inflow points and port from least to most active. Validate seal by observing reduction in infiltration under normal head.
For Civil Contractors (Business Owner/Operator): Rapid mobilisation on tunnels or culverts
The Professional's Challenge
Multiple leak points with limited possession windows demand fast setup and predictable outcomes.
The Adheseal Solution: Engineered Certainty in Practice
Single-component pumping streamlines plant and labour. Hydrophobic reaction tracks water to seal beyond visible defects, reducing call-backs and downtime.
Best Practice Note
Sequence teams by zone, standardise Accelerator “B” dosages per ambient temperature band, and document backflow/pressure response for QA.
Frequently asked questions
How do I control grout gel and rise times?
Adjusting Accelerator “B” directly controls reaction speed. At 25°C, 1.25% Accelerator “B” starts expansion at 50 seconds, completing in 4 minutes. Increasing to 2.5% Accelerator “B” accelerates this to 15 seconds start and 65 seconds completion.
Does Mountain Grout Flexible require water to react?
Yes, the hydrophobic formulation requires water contact to foam and expand. For very dry crack sections, pre-wetting ensures a consistent reaction, but avoid flooding that could wash out the resin.
Is this grout suitable for long-term wet/dry cycling?
Yes, the cured grout forms a stable, closed-cell, hydrophobic foam. This material is designed to retain its physical form and resist shrinkage under prolonged wet/dry conditions, ensuring durable water cut-off.
What are the key cured properties of the foam?
The cured foam has a typical density of 64 kg/m³ and an elongation of 44%, allowing it to handle crack movement. Water absorption is less than 1%, and the material is inert and non-toxic once cured.
Applications and benefits
| Application | Key benefit | Primary trades |
|---|---|---|
| Seal leaking cracks in concrete structures | Forms a hydrophobic, closed-cell foam that maintains a seal through wet/dry cycles. | Remedial waterproofers, civil contractors |
| Stop infiltration at manholes and vaults | Expands up to 30 times to chase water paths, creating a robust grout curtain. | Asset maintenance, wastewater utilities |
| Restore watertightness at concrete construction or cold joints | Controlled reaction times ensure the resin foams in situ before washout can occur. | Engineers/specifiers, remedial waterproofers |
| Leak cut-off in tunnels, culverts, and dams | Single-component pumping capability accelerates mobilisation and increases on-site throughput. | Civil contractors, infrastructure maintenance |
| Waterproofing elevator pits and parking structures | Provides a durable, inert, non-toxic seal for long-term service without degradation. | Remedial waterproofers, facility maintenance |
Applying Mountain Grout Flexible: Enhanced Protocols & Best Practices
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Assessment & Preparation
Identify leak sources, map water paths, and select port locations to progressively intercept flow. Clean and seal around ports to contain resin during rise.
Leak Mapping
Start at the lowest/outlet point and work upstream. Mark damp areas for pre-wetting if required.
Port Strategy
Use close spacing in thick sections and where flow paths branch. Prepare for staged injections.
Timing: Allow sufficient setup to keep injection continuous once started.Pro Tip: Pre-wet very dry sections to support consistent reaction without risking washout. -
Resin Setup & Accelerator Dosing
Dose Accelerator “B” into the base resin before pumping to suit site temperature and leak rate.
Standard Seepage
~1.25% “B” for start ~50 s and completion ~4 min at 25 °C, promoting deeper penetration before rise.
High-Flow Leak
~2.5% “B” for start ~15 s and completion ~65 s at 25 °C to minimise washout risk.
Timing: Reaction accelerates at higher temperatures and slows when cooler; adjust dosage accordingly.Pro Tip: Mix thoroughly and keep records of dosage vs ambient temperature for repeatable results. -
Injection & Monitoring
Pump as a single component. Begin from the lowest/most downstream port and progress sequentially to upstream ports.
Controlled Pressure
Use modest pressures to favour in-situ foaming and prevent resin bypass.
Verification
Watch for backflow or moisture changes at adjacent ports; proceed once the path is saturated.
Timing: Maintain continuous pumping during the gel window for each port.Pro Tip: If washout is observed, increase “B” dosage and re-stage from downstream. -
Post-Injection QA
Observe leak reduction under the prevailing head. Remove ports and make good once performance is confirmed.
Functional Check
Confirm no visible inflow; monitor for rewetting after pressure equalises.
Documentation
Record port sequence, dosages, and outcomes for asset records.
Timing: Allow foam to fully develop per selected reaction profile before removal.Pro Tip: Re-check after rainfall or system surges to verify long-term stability.
Product limitations
- Not for: Applications without water present; the resin requires water contact to react and expand. Very dry cracks may need pre-wetting.
- Not for: Surface-applied cosmetic crack filling; this product is designed specifically for injection and subsurface sealing.
- Note: Reaction times will vary with ambient temperature and moisture levels; adjust Accelerator “B” dosage accordingly to suit site conditions.
Safety and handling
Personal protective equipment
Wear chemical-resistant gloves, eye protection, and suitable workwear to avoid skin and eye contact.
Ventilation
Use in well-ventilated areas. For enclosed spaces, ensure adequate airflow and comply with confined-space protocols if applicable.
First aid
- Eyes: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do, then continue rinsing.
- Skin: Wash with soap and water. Remove contaminated clothing and launder before reuse.
- Inhaled: Move to fresh air and keep at rest in a position comfortable for breathing.
- Swallowed: Rinse mouth. Do not induce vomiting. Seek medical attention.
Substrate guide
Proper surface preparation and moisture management are critical for effective leak sealing.
Concrete – Active leaking crack
Surface prep: Identify the water path and install injection ports to intercept the flow. Clean surfaces around ports for proper sealing. Pre-wet adjacent dry areas to ensure water contact without causing washout.
Primer: Not required. Focus on ensuring water presence and correct port placement for effective injection.
Concrete – Damp or seeping crack
Surface prep: Map the seepage area, remove loose fines, and ensure a consistent moisture film is present. Consider a moderate Accelerator “B” dosage to allow deeper penetration before foaming.
Primer: Not required. Maintain steady injection pressure and monitor for backflow at adjacent ports to ensure full crack saturation.
Concrete – Cold or construction joint
Surface prep: Port along the joint line to intercept leak planes. Remove loose laitance at port faces and seal the surface to contain the resin during expansion.
Primer: Not required. Select Accelerator “B” dosage based on the observed inflow rate and the ambient temperature.
Manholes and pipe penetrations in concrete
Surface prep: Expose annular paths, install ports to encircle the penetration, and ensure moisture contact along the leak path. Clean the surface for sealant adhesion around port collars.
Primer: Not required. Stage injections to build a complete grout curtain around the penetration, ensuring full encapsulation.
Mountain Grout Flexible Physical Properties
| Property | Value |
|---|---|
| Base Chemistry | Hydrophobic polyurethane |
| Curing System | Single-component |
| Colour | Amber (base resin), clear (Accelerator B) |
| Density | 64 kg/m³ |
| Viscosity Base Resin | 500 mPa·s |
| Viscosity Accelerator B | 25 mPa·s |
| Flash Point Base Resin | >121°C |
| Flash Point Accelerator B | 107°C |
| Tensile Strength | 0.20 MPa |
| Shear Strength | 0.12 MPa |
| Elongation | 44% |
| Expansion Ratio | Up to 30x |
| Cure Rate | Start ~15 s, complete ~65 s (with 2.5% Accelerator B at 25°C) |
| Water Absorption | <1% |
| Substrate Compatibility | Cracked/damp concrete, construction joints, manholes, tunnels, dams, vaults, elevator pits, parking structures |
| VOC Content | No VOCs (100% solids) |
| Standards | ASTM D-1638 (foam density), ASTM D-1475 (specific gravity), ASTM D-92 (flash), ASTM D-1622 (density), ASTM D-638 (tensile/elongation), ASTM C-273 (shear), ASTM D-2842 (water absorption) |
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