Injection method for masonry with cavities

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Injection method for masonry with cavities

Due to a multistage injection in a low-pressure process, cavities, defects and fissures are filled with a shrinkage-free injection mortar via bore packers. Using the same packers, a drill channel is created by a lance. The injection material is then injected by pressure injection (3-5 bar) for better distribution. In this way an optimal effectiveness in the area of the injected masonry can be achieved.
Horizontal sealing / Horizontal barriers
Subsequent injection against capillary ascending moisture

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  • Prevention of moisture flow by capillary action
  • Moisture content in equilibrium with environment
  • Prevention of capillary moisture replenishment above the injection zone

Objectives of low-pressure injection

  • In the case of masonry of homogenous materials
  • In the case of masonry with a high rate of moisture transport
  • Consistent and rapid distribution of injection material throughout the masonry


  • Machine pressure injection contributes to optimal distribution of filling material in masonry
  • Packer systems and fittings optimized for the technique
  • Strengthening and stabilization of masonry in the injection area
  • Low consumption of injection fluid through filling of internal cavities

Types of packers

  • Bore packers (steel)
  • Drive-in packers (polymer)

Requirements with regard to Injection and Mixing Equipment

  • Cross section adjusted to the flow characteristics of the injection material
  • Pressure controlled and limited to between 1 and 15 bar
  • Corrosion resistance of all equipment parts vis-a-vis injection material
  • Homogenous mixing of injection material
  • Consistent mixing quality
  • Keeping the injection material in motion
  • Pump performance and flow suitable to the masonry


  • The horizontal seal should only be injected above the pressure and water line

Additional information in German: „Injektionsverfahren mit zertifzierten Stoffen gegen kapillaren Feuchtetransport“ WTA Merkblatt E.4-10, Ausgabe 03.2015/D.

Wet-on-Wet Technique and Multistage Injection (INJECTION PASTE AND MICRO EMULSION)

Objectives of the Wet-on-Wet Technique

  • Filling of the internal cavities to create an injection zone to contain the micro emulsion
  • Stabilization of the masonry in the area being injected
  • Increase of alkalinity in the area injected to allow the micro emulsion to react

Filling materials

  • Injection of paste (step 1)
    • to fill cavities and crevices
  • Injection of micro emulsion (step 2)
    • to create a horizontal seal

Objectives of Multistage Injection

  • In the case of masonry of homogenous materials and a low alkalinity, the chemical reaction is started using an activator

Procedure Wet-on-Wet Technique – Step 1

  • Prepare drilling by marking the positions of holes every 10 to 12.5 cm (4 to 5 inches) then drill and remove dust with a moist cloth or brush
  • Insert packers, clamp, and attach shut-off pieces
  • Mix injection paste
  • Fill the injection pump with mixed material
  • Inject the drill holes at a pressure of approximately 2 bar (depending on masonry)


Procedure Wet-on-Wet Technique – Step 2

  • When injection pressure has dropped sufficiently (when material stops flowing out of the shut-off piece) insert the test lance into the packer. The channel for the second injection is ready when the injection paste has hardened enough that the test lance can be withdrawn
  • Mix micro emulsion and inject into drill holes at a pressure of approximately 5 bar (depending on masonry)
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