Features and Benefits

For fixing Expanded Polystyrene (EPS) boards as well as for applying a thin armoured layer for thermal insulation of buildings by means of light wet method


  • flexible
  • highly impact resistant
  • unique fibre combination
  • resistant to weather conditions
  • resistant to hairlines and cracks
  • high adhesion to mineral substrates and EPS-boards

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Ceresit CT 85 mortar is designed to warm up external walls of the buildings with the application of a light-wet method and EPS-boards. It is an element of ETICS (External Thermal Insulation Composite Systems) within Ceresit Ceretherm. CT 85 mortar is used for fi xing EPS-boards as well as applying the armoured protection layer to insulate the newly erected objects and also the buildings to be thermo-renovated. CT 85 through the use of a highly targeted combination of special fi bres, increases the resistance of insulation system on damage and resistance to the formation of cracks and hairlines.

Step By Step

Substrate preparation


Preparing the reinforced layer - after the adhesive set in (after 2-3 days) boards should be threated with sandpaper and additionally fixed using mechanical anchors.

Mortar preparation and application


CT 85 should be poured into the measured amount of cool clean water and stirred with the drill by means of a mixer until the homogenous mass is obtained without lumps. Armoured layer application - the ready mortar of 2-3 mm-thick layer should be spread along the surface of the boards by means of a smooth long steel float. The glass fibre mesh should be applied on the fresh mortar (with 10-cm overlaps).

Filling the mesh


In the next step, the freshly applied mesh, which has been immersed in the adhesive mortar layer, should be thoroughly smoothened with a long steel float.


The next layer can be applied (thickness 1 mm) and smoothed in order to completely hide the reinforcement mesh.