Over-working of painted facades

Check of substrate

1. Inspect the facade for hollow spots and knock off all hollow areas.

2. Cut the paint into small squares of approx. 2 x 2 mm on an area of 10 x 10 cm. If 80 % of the cut squares remain adherent, the coating is described as adherent.

3. Check the compatibility or the adhesion of the reinforcing mortar, for ex. weber.therm 300 (not necessary in the case of silicate and dispersion silicate paints) on the paint. Insert the reinforcing fabric weber.therm 310 in the mortar and tear it off after 7 days.

Preliminary works

4. If the paint sticks to the reinforcing mortar during the substrate check, the paint must be removed.

5. It is recommended to use the patented system weber.therm retec® 700, if the old paint cannot be removed completely and the adhesion of the reinforcing mortar is not sufficient.

6. As a rule, clean the facade with a high-pressure cleaner prior to rendering works.

Application

7. In case of active cracks, knock off the render 20 cm on both sides of the cracks. Fix the glass fiber joint mat weber.therm Glasfaser-Fugenmatte with the bonding and reinforcing mortar weber.therm 300. In case of larger movements within the substrate, lay a corrugated paperboard for purpose of de-coupling. Place a galvanised, welded wire mesh (for ex. Distanet) tension-free and apply the lightweight lime-cement underlay render weber.dur 132.

8. Apply a reinforcing mortar, like weber.therm 300 in approx. 6 mm thickness.

9. In case of cracks, the woven mesh weber.therm 310 must be laid in the upper half of the mortar layer. If dispersion-based has not been removed, a dowelling (4 pieces/m2) should be carried out.

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. Depending on the type of overlay render the surface is textured or scratched with an appropriate tool.