Application of thick-layer mineral scratch renders

Mineral scratch overlay render is a classic and timeless topcoat, that is currently experiencing a true revival. With the application tips described herebelow, you will achieve an optimal working result.

Simple & safe to the goal

  1. Suitable substrate

    The lightweight lime-cement fiber-reinforced underlay render weber.dur 137 or the bonding and reinforcing mortar weber.therm 300 must be roughened horizontally with a notched trowel, a comb or a hard broom.

  2. 2. Spray/apply the mineral coarse-graded scratch top render weber.top 204 AquaBalance and strike off to grain thickness in a thickness of 10 - 15 mm.

  3. 3. The lowest rebound and the optimum spray pattern is obtained by using an extended spray nozzle.

  4. 4. After spray application, the scratch render is ruled level with a notched aluminium lath (plasterer’s darby) to remove trapped air bubbles.

  5. 5. Leave rough the surface of the scratch render. This makes the scratching works easier.

  6. 6. Before scratching works begin, brush a coloured pigment over the surface. Afterwards, start the scratching works. The right time for scratching is when the grains "spring".

  7. Corner design with edge protection angle

    1. The edge protection angle is fixed with the profile bonding and installation mortar weber.mix 125 on the masonry. Respect the specific render thickness. The masonry is subsequently covered with an underlay render, e.g. weber.dur 132.

  8. 2. As a rule, the mortar must be force-fitted with the edge protection angle.

  9. 3. In the area of an edge protection angle, always scrape from the corner into the main surface.

  10. Corner design without edge protection angle

    1. For achieving a plumb corner, a plaster lath, preferably a wooden lath or similar, is posted. The masonry is then covered with an underlay render, e.g. weber.dur 132).

  11. 2. Again, a render lath is held at the corners. After the scratch render has been applied, it is urgently necessary to "smooth in" the corner areas.

  12. 3. For scraping corner areas, hold a wooden batten or similar to the corner again and scrape from the corner to the main surface.