Renovation with lime and trass lime plasters in the preservation of historical monuments

Here, a possibility is shown how to renovate historical without using lime-cement plasters, but only lime and trass lime plasters.

Simple & safe to the goal

Preliminary works

1. Completely knock-off old and non-load-bearing render.
2. Scrape out non-load-bearing joints.
3. Clean the whole facade.
4. In the case of high-porosity substrates and/or substrates with different porosity apply the normal-setting stipple coat weber.san 160 WTA in order to obtain a surface with uniform porosity.
5. The lime underlay render/plaster weber.cal 172 or the trass lime render weber.san 171 is applied in a thickness of 15 -20 mm in 2 layers "wet-in-wet".
6. In case of over-thickness, the first layer of weber.san 171 or weber.cal 172 is combed horizontally.
Application

7. After a waiting time of a minimum of 1 day per mm thickness, a further layer of 15 - 20 mm can be applied.
8. Depending on the type of post-applied overlay render, the surface is roughened or combed horizontally.
9. Respect a delay of 1 day per mm thickness for weber.san 171 or weber.cal 172. Then apply the fine-graded (grain size 1 mm) trass lime underlay render/plaster weber.cal 172 and work to the individual texture by smoothing the fresh mortar.
10. Depending on the type of overlay render and weather conditions, the reinforcement layer must be eventually pre-wetted or pre-treated with the universal primer weber.prim 403.
11. The overlay render is hand or machine applied.
12. Depending on the type of overlay render the surface is textured or scratched with an appropriate tool.