ACTFLEX INJECTSWELL PU injection grout
Single-component hydrophilic polyurethane injection grout
Hydrophilic polyurethane grout that swells on water contact to seal leaking cracks from within.
ACTFLEX INJECTSWELL sizes and key figures
Single-component, low-viscosity hydrophilic polyurethane injection grout. It reacts on contact with water and swells into a flexible seal inside leaking cracks, joints and voids in concrete, brick and mortar.
- Viscosity
- 450–600 mPa·stypicalat 25°C, fine fissures · TDS p2
- Cream time
- 48 secondstypicalat 25°C · TDS p2
- Rise time
- 302–343 stypicalat 25°C, depends on water ratio · TDS p2
- Free rise
- 4.3–6.4×typical1:1 water to resin gives 4.3×, 1:4 gives 6.4× · TDS p2
- Elongation
- > 400%typicalthin sections; > 34% in thick sections · TDS p2
- Bond strength
- > 0.28 MPatypicaladhesion to concrete, brick and mortar · TDS p2
- Full reaction
- 24 hourstypicalstable seal · TDS p3
- Apply at
- Above +10°Cdo not apply below 10°C · TDS p2
- Pack
- 10 kglight brown liquid · TDS p2
From the FORSPEC data sheet, TDS-INJECTSWELL · Revision 2 · 12 November 2026. Times are at 25°C and 50% relative humidity unless the data sheet says otherwise. Typical = FORSPEC’s own typical value, not a laboratory-certified one.
Where ACTFLEX INJECTSWELL is used
Use it for
- Crack injection: sealing active leaks and filling voids in concrete
- Basements, tunnels and underground car parks
- Retaining walls and dams: expansion and construction joints, cracks
- Sewage and water treatment plants, sewer pipes and water tanks
- Bridge decks, culverts, tunnel linings and rock fissures
- Precast concrete joints, pipe penetrations and manholes
Know before you start
- Not a membrane and not a structural repair: use the FORSPEC epoxy crack range
- Needs enough water in the substrate to gel, otherwise it expands to a foam
- Not where the crack will dry out permanently: the seal shrinks under wet and dry cycling
- Do not apply below 10°C. Not for contact with potable water
Its FORSPEC systems
How to apply ACTFLEX INJECTSWELL
- 01
Prepare
Confirm the crack location, extent and water regime, and record the leak rate. Clean off loose material. Where surface leakage is heavy, stop it first with ACTFLEX HYDROPLUG and detail with ACTFLEX FLEXIPLUG.
- 02
Packers
Drill and set injection packers to a pattern set by crack width, wall thickness and the project design. Flush with clean water to confirm communication, and add water where the substrate is dry.
- 03
Inject
Use single-component injection equipment. Start at the lowest packer and work up until resin comes from the packer above. Keep pressure within the limit set by the project engineer.
- 04
Re-inject
Re-inject any packer that still accepts resin after the first reaction. Flush the pump and lines with urethane thinner straight after use, and reseal the container at once.
- 05
Finish
Once fully reacted (about 24 hours), remove the packers, reinstate the holes with a FORSPEC repair mortar and trim flush. Re-inspect for leaks 24 hours after full reaction.
A short guide from the data sheet. Read the full ACTFLEX INJECTSWELL TDS before you start.
Drawings for the systems it goes in
FORSPEC standard details as PDF and DXF. Each sheet is a generic detail: the specification names the products.
ACTFLEX INJECTSWELL questions
What does hydrophilic mean for INJECTSWELL?
It swells by taking up water, forming a flexible seal inside the crack that keeps responding to water. Free rise is 4.3 to 6.4 times, depending on the water-to-resin ratio.
Does the crack need water in it?
Yes. With too little water it expands to a foam instead of a gel seal. Flush the crack and introduce water before injection where the substrate is dry.
How fast does it react?
Cream time is 48 seconds at 25°C and rise is complete in about 302 to 343 seconds, depending on the water ratio. Full reaction takes about 24 hours (typical values).
How much resin do I need?
There is no fixed rate. Estimate void volume divided by the free rise ratio, plus an allowance for travel beyond the void and for pump and line priming. Confirm on the first section injected.
Is there a mix ratio or pot life?
No. It is single-component. Do not dilute it or mix it with any other product, and reseal the container straight after use because it reacts with moisture in the air.
Can it be used where the crack dries out?
No. The cured hydrophilic seal depends on retained moisture and will shrink under sustained wet and dry cycling.
Used with ACTFLEX INJECTSWELL
ACTFLEX INJECTSWELL data sheet
Always work from the current data sheet. Every FORSPEC TDS and SDS →
Specify it. Or buy it.
Send the drawings or photos and FORSPEC comes back with the system, the details and the quantities. Or find a FORSPEC stockist for ACTFLEX INJECTSWELL.