Rendering of old brickwork, quarry natural stones (poorly absorbent substrates) and mixed masonries

The plaster's capillary adhesion on weakly absorbent substrates can develop poorly. Therefore, a larger surface must be created thanks to a stipple coat as a bond coat for sufficient mechanical bonding.
In the case of mixed masonries, a reinforcing fabric should be embedded in the rendering shell due to the different deformation properties of the stones.

Simple & safe to the goal

  1. Check of substrate

    1. Check the substrate porosity and test if load-bearing.

  2. Preliminary works

    2. Apply the cement stipple coat weber.dur 100 wart-like (with a surface coverage of 50%), so that the substrate is still clearly visible (for ex. in the case of low-porosity substrates, e.g. concrete blocks, highly-fired bricks, and quarry stones). For large-size quarry, natural stones use the normal-setting stipple coat weber.san 160 WTA due to its better bonding strength.

  3.  

    3. Apply a fiber-reinforced lightweight render, e.g. weber.dur 137 in one layer of 15-20 mm. Depending on the type of topcoat (overlay render). Leave the surface of weber.dur 132 as required for the specific overlay render (top coat).

  4. 4. In the case of mixed masonries the bonding and reinforcing mortar weber.therm 300 and the woven mesh weber.therm 310 are applied. Leave the surface as required for the specific overlay render (top coat).