Ceresit CT 83 Adhesive mortar for EPS

• High adhesion to mineral substrates and EPS-boards
• Economical in consumption
• Quick increase in strength
• Vapour permeable
• Amount required: approx. 5.0 kg/m2

CT 83 mortar is designed to apply EPS-boards within Ceresit ETICS (External Thermal Insulation Composite Systems) with a light-wet method Ceresit ETICS systems. CT 83 mortar is used for applying to the newly erected objects as well as the buildings to be thermo renovated. The applied boards require additional fixing by means of mechanical anchors, i.e. proper expansion pins made of plastic. Ceresit CT 85 mortar should be used to apply fibre glass reinforced layer on the EPS-boards. In case of the walls insulation with facade mineral wool boards, WM Ceresit CT 190 mortar should be used.

Ceresit CT 83 shows very good adhesion to sound and carrying substrates, such as wall, plaster and cement sub- strates free from grease, bitumen, dust and other substances decreasing adhesion. The adhesion to the existing plasters and paint coatings should be checked before starting the application. “Hollow” plasters should be removed. Any losses and uneven surfaces of the substrate below 20 mm should be filled with the filler CT 29 or covered with cement plaster. Any surface contaminant and other adhesion impairing substances, steam-tight paint coatings and the coats with low adhesion to the substrate should be completely removed, e.g. by means of washing devices operating under pressure. In case of mycological contamination with fungi, moss and algae, the surface of the façade should be cleaned with steel brushes and, then saturated with a fungicide solution of Ceresit CT 99 in compliance with technical instruction. The old, not plastered walls, strong plasters and paint coats should be dusted, then washed with water jet and left until they go completely dry. Substrates with high water absorption, e.g. walls made of aerated concrete blocks or silicate blocks should be primed with Ceresit CT 17 and left for drying for at least 4 hours.

CT 83 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. The ready mortar should be applied with a trowel along the board edges forming a strip of 3÷4 cm wide and a few spots with the diameter of approx. 8 cm. Then immediately, the board should be pressed to the wall with a few slight blows of a long float. The properly applied mortar when pressed should cover minimum 40 % of its surface. In case of even, smooth substrates the mortar should be applied by means of a toothed long float (teeth 10–12 mm). The boards should be fixed tightly one at the other in one surface with the preservation of ”brick like manner’’ of vertical connection. When CT 83 is set (after approx. 2 days), any unevenness of the boards should be ground with abrasive paper, then the boards should be additionally reinforced with mechanical anchors. The number of anchors should be min. 4 per m2. The stripes of 2 m wide located along the building edge are exposed to the biggest wind powers and the number of anchors should be increased in these places up to min. 8 per m2. Fresh stains should be cleaned with water while hardened elements should be mechanically removed only.