Repair of cracks - horizontal bed joint repairs

Reconstruction targets

Obstruction of the movement of existing cracks and prevention of the formation of new cracks at other positions in the masonry –

i. e. masonry reinforcement for a damage-free deflection of future loads

Reconstruction procedures

Embedding of Ruberstein® Spiral Anchors using Ruberstein® Anchor Grout in previously opened joints or slits of the existing masonry in horizontal direction to the wall level

Advantages of the Ruberstein® Spiral Anchor System

  • Flexible crack bridging without load concentrations and thus long-lasting joining of cracks with high safety against new crack formation in spite of still existing component deformation
  • Simple processing, no heavy machinery necessary
  • Little invasion into the building structure

Construction rules

  • Laying direction preferably horizontal, or vertical to the course of the crack
  • Anchor diameter preferably Ø 8 mm or Ø 10 mm

  • Anchor length / distance from course of the crack ≥ 40 cm on both sides, additionally lateral offset of approx. 20 cm in case of several vertically consecutive anchor positions, overall length min. 100 cm

  • Number of anchors according to measuring, or vertical distance of the anchor positions ≤ 35 cm constructively

  • Please observe anomalies in border areas, near wall openings as well as in corner formations and arches (if necessary ask for sketches with detailed solutions)

  • If possible, bridge crack groups with common, longer spiral anchors

  • Overlap joints ≥ 50 cm

  • Anchor grout with     spiral anchor

  • Slit height (h) usually 10...20 mm (or height of the horizontal joint)

  • Slit depth (t) usually 40...50 mm (observe static stability)

  • effective joint circumference (t + 0.5 h) ≥ 50 mm

  • Laying depth of the spiral anchors in the wall section ≥ 20 mm (without plaster layer)

Material and accessories

Ruberstein® Spiral Anchors, type Standard (without tip)

Ruberstein® Anchor grout

Commercially available wall chaser/slitter or angle grinder

Mortar gun (with standard jet)


Video repair of cracks


  1. Cut the joint e. g. with wall chaser
  2. ‚Blow out the joint, moisten with water

  3. Apply first layer of anchor grout with mortar gun into the joint

  4. Cut spiral anchor to length, press into anchor grout

  5. Apply second layer of anchor grout into the joint

  6. Close the remaining joint with anchor grout or coloured joint mortar

  Joint / slit depth tF
25 mm30 mm40 mm50 mm60 mm70 mm
Consumption per m 0,30 l 0,37 l 0,49 l 0,62 l 0,75l 0,87l
Yield per bucket (6 l) ≈ 20 m ≈ 16 m ≈ 12 m ≈ 10 m ≈ 8 m ≈ 7 m


Calculated consumption / yield of the Rubersteinâ Anchor Grout (joint/slit height hF = 12 mm, anchor volume neglected)

Crack reconstruction accompanying applications

Stabilisation of building corners/building sections

Replacement of ring anchors/circular beams; utilization of barrel effect (e. g. chimney reconstruction)

Subsequent masonry reinforcement / formation of reinforced lintels