ACTFLEX HYDROPLUG Plugging cement
Rapid-setting water-stop plugging cement
Rapid-setting plugging cement that stops active water leaks, even under pressure.
ACTFLEX HYDROPLUG sizes and key figures
Single-component, non-shrink cementitious plug mixed with clean water to a putty and pressed by hand into cracks, holes and junctions in concrete and masonry. It is the first step before FLEXIPLUG detailing and a FORSPEC membrane.
- Hand-set
- 2–4 mintypicalafter placement, at 25°C and 50% RH · TDS p2
- Final set
- 10 mintypicalfinal solidification; initial within 5 minutes · TDS p2
- Water
- 150 mL per kgof powder, mixed to a putty. The ratio is critical · TDS p2
- Batch size
- ≈ 0.5 kgmixed by hand with a spatula only · TDS p2
- Strength
- ≥ 4.5 MPatypicalcompressive at 1 hour; ≥ 15.0 MPa at 3 days · TDS p2
- Yield
- ≈ 0.50 Ltypicalper kg of powder, placed density approx. 2.2 kg/L · TDS p2
- 20 × 20 mm chase
- ≈ 0.8 kg/mtypicalabout 25 m per 20 kg pail · TDS p2
- Apply at
- +5°C to +35°Cambient and substrate · TDS p2
- Pack
- 5 kg, 20 kgpails of grey powder · TDS p2
From the FORSPEC data sheet, TDS-HYDROPLUG · Revision 3 · 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.
ACTFLEX HYDROPLUG on site
More FORSPEC jobs
Where ACTFLEX HYDROPLUG is used
Use it for
- Active leaks in non-potable water tanks and retention structures
- Basements, underground car parks, lift shafts and lift pits
- Concrete pipes, tunnels, power stations and sewer systems
- Wall/floor junction water-stop within the ACTFLEX 988 CWP system
- Sealing around penetrations ahead of ACTFLEX FLEXIPLUG detailing
- Rapid anchoring of bolts, pipes, conduits and sanitary fittings
Know before you start
- Not for expansion or movement joints: use ACTFLEX FLEXIPLUG
- Not a stand-alone membrane: finish with ACTFLEX 988 CWP or the specified membrane
- Cementitious substrates only; never below +5°C, above +35°C or on frozen surfaces
- Not for potable water: do not use in drinking-water tanks or potable water structures
How to apply ACTFLEX HYDROPLUG
- 01
Prepare
Grind the opening to at least 20 mm deep and wide (40 mm for high-volume leaks). Square-cut or dovetail it, never a V. Flush with clean water and keep it damp.
- 02
Mix
150 mL clean water per 1 kg of powder, about 0.5 kg per batch. Mix by hand with a spatula only, to a stiff putty. Hold it in a gloved hand until it feels slightly warm.
- 03
Place
Press the putty firmly in against the flow and hold it for 30 seconds to 1 minute. On larger leaks work from the edges inward. It hand-sets in 2 to 4 minutes.
- 04
Cure
Mist with clean water or hold a damp sponge on the repair for 15 minutes. Sand or grind it to match the surrounding contours if needed.
- 05
Complete
Once the flow has stopped, complete the detail with ACTFLEX FLEXIPLUG, then over-coat with ACTFLEX 988 CWP or the specified FORSPEC membrane.
A short guide from the data sheet. Read the full ACTFLEX HYDROPLUG 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 HYDROPLUG questions
How fast does ACTFLEX HYDROPLUG set?
Hold it in place for 30 seconds to 1 minute, then it hand-sets in 2 to 4 minutes. Initial solidification is within 5 minutes and final within 10 (typical values at 25°C and 50% RH).
How do I mix it?
150 mL of clean water per 1 kg of powder, in batches of about 0.5 kg, by hand with a spatula. Never use an electric mixer. Mix to a stiff putty and use it straight away.
How much do I need?
About 0.8 kg per metre for a 20 × 20 mm chase and about 3.2 kg per metre for 40 × 40 mm. A 20 kg pail gives about 25 m at 20 × 20 mm. These are typical figures, so allow for wastage.
Is HYDROPLUG a waterproofing membrane?
No. It is a rapid water-stop and repair compound. Complete the detail with ACTFLEX FLEXIPLUG and over-coat with ACTFLEX 988 CWP or the specified FORSPEC membrane.
Can I use it in a movement joint?
No. It is not for expansion or movement joints. Moving details are the role of ACTFLEX FLEXIPLUG.
Can it anchor bolts and pipes?
Yes. Prepare and dampen the cavity, place the putty, position the fixture straight away and hold it still until set. Apply no load before the fixing has developed enough strength.
Used with ACTFLEX HYDROPLUG
ACTFLEX HYDROPLUG TDS and SDS
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 HYDROPLUG.