Water Plug, Rapid Setting Mortar to Plug Active Water Leaks

ISONEM M 36 is a cement based water plug that instantly stops running water. When contacted with water, it plugs the water by taking a set in two seconds.

Cement based, rapid setting plug mortar for stopping the leakages. when mixed with clean water, provides a ready to use ultra rapid setting durable plugging mortar for active water leaks in concrete and masonry. The material expands as it cures to form a watertight seal with similar characteristics to concrete.


ISONEM M 36 is used to stop active water or seepage under pressure through joints, cracks and holes in concrete or masonry, where a normal mortar would be washed away and resin mortars would not bond.

Can also be used:

  • As a seal for construction joints or floor joints prior to basement tanking with ISONEM M 34, ISONEM MD 28, ISONEM MD 27, ISONEM M35, ISONEM M35-3K.
  • For instant sewer connections.
  • For sealing cracks and construction joints in reservoirs and other water retaining structures.
  • For rapid anchoring of bolts, conduits, pipes, railings, sanitary equipment, etc.
  • Joint filling, pointing between concrete segments in concrete and brick tunnels, sewage systems, concrete pipes and mines.

Features & Benefits

  • Ultra-rapid set, instant plugging of leaks
  • Requires the addition of water only
  • Expands as it sets, ensuring a permanent watertight seal
  • Similar characteristics and compatible with concrete
  • Chloride-free
  • Does not promote corrosion of the reinforcement

Technical Properties

  • Wet Density: kg/m 3 : 2140
  • Maximum particle size: mm : 0.8
  • Compressive strength: N/mm²
    • 30 minutes : 14
    • 24 hours : 31
    • 7 days : 42
    • 28 days : 53
  • Flexural strength: N/mm2
    • 30 minutes : 2.7
    • 24 hours : 6,1
    • 7 days : 6,3
    • 28 days : 7
  • Tensile strength, N/mm2  . 28 days : 3.3

(Typical values at 20°C)

Preparation of Substrate

Preferably, cracks or holes should be cut out to a minimum width and depth of 20mm, cutting the sides as square as practicable. Undercut if possible. Avoid leaving a V-section. Do not feather-edge. Flush out the hole or crack with water at high pressure in order to remove all loose particles and dust.

All surfaces must be dampened with clean water immediately prior to the application of ISONEM M 36.

Mixing & Application

Mixing should only be done by hand.

For Plugging Active Leaks

  • Mix, in a rubber bowl, only sufficient material (0.5kg) that can be placed by hand in one application.
  • Mix quickly and well to a stiff consistency (approximately 1 part of water to 4 parts of ISONEM M 36 by volume). Do not overmix.
  • Hold the material in the hand until slight warmth is felt or setting occurs.
  • Then press ISONEM M 36 mortar firmly into the opening; exert full pressure, without moving the hand or trowel.
  • Do not remove the hand too quickly. If the opening is too big to be closed with 0.5kg of ISONEM M 36, work from the sides to the middle, following the above procedure.
  • After stopping the active water, trim off the patch so that it is uniformly level with the surrounding wall surfaces. For sealing cracks at the junction of floor and wall in an existing construction:
  • Cut out the crack at least 20mm wide and deep, cutting back into the wall slightly.
  • Flush away all cuttings and dirt.
  • Force ISONEM M 36 mortar into the prepared crack and smooth it out.
  • Form a 45o cove or fillet at the junction of floor and wall of approximately 35-45 mm.

For sealing the junction between a concrete floor and a masonry wall in new construction

  • Form a rebate throughout the basement and subbasement rooms and pits by inserting a strip of wood 20mm x 20mm at the junction of vertical masonry walls and the concrete floor slabs.
  • The top edge of the strip should be laid true and level with finished concrete floors and left in place until fresh concrete has cured.
  • Wash the groove with clean water from a hose pipe to remove debris.
  • Fill the groove with ISONEM M 36 mortar mixed to a stiff consistency; force or tamp it into place with a round-nosed tool to form a cove between the floor and wall.
  • Keep the ISONEM M 36 mortar damp for 15 minutes if no active water is present.

To repair leaking mortar joints and cracks in masonry walls, or cracks in concrete walls

  • Cut out the defective mortar joints or cracks to a minimum width and depth of 20mm. Undercut if possible.
  • Force ISONEM M 36 into the crack and keep it damp for at least 15 minutes.

For holes, blisters, patches, honeycomb and other construction faults in concrete walls

  • Remove all tie wires, wood or steel separators by cutting back the concrete from the surface to a depth of 25mm.
  • Mix ISONEM M 36 with water to the consistency of stiff mortar and fill all holes, blisters, patches, honeycombing and other construction faults flush with the surrounding surfaces.
  • Scratch the finish for later applications.

For anchoring bolts or metal posts in concrete or masonry

  • Drill a hole deep enough to secure the bolt or post properly and large enough so there is at least 10mm on all sides of it.
  • Fill the hole with ISONEM M 36 mortar and tamp it down so that the entire hole is full.
  • Immediately centre the bolt or post over the hole and force it into the ISONEM M 36 mortar.
  • Tamp the ISONEM M 36 mortar firmly around the bolt or post and keep moist for 15 minutes.

Notes On Application

  • Curing:
    • Final setting time, 2 – 4 minutes. Once the placed ISONEM M 36 mortar has stiffened sufficiently, dampen with clean water and maintain in a damp condition for a minimum of 15 minutes. ISONEM M 34 is applied in 3 layers as the constant insulation to complete the process.
  • Consumption:
    • 2 kg powder will fill 1 liter space
  • Package:
    • 20 kg pail
  • Storage:
    • In cool and dry places 12 months. Once opened the material should be used as soon as possible.

Health & Safety Information

For information and advice on the safe handling, storage and disposal of chemical products, users shall refer to the most recent Material Safety Data Sheet containing physical, ecological, toxicological and other safety-related data.