BK-Mal 420

Cement-lime mortar for exterior walls

BK-Mal 420

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Reinforced cement-lime mortar for mechanical and manual application on exterior and interior walls of brick, blocks, siporex blocks and concrete. The product is applicable for sanitary blocks, for surfaces on which ceramics will be installed. The product is characterized by high mechanical strength and good adhesion to the substrate, so this type of mortar is particularly suitable where later heavy wall elements will be installed.


The substrate to which the mortar is applied should be solid, clean and dry, free of poorly bonded parts and greasy stains. The closure of holes, joints, electrical openings should be performed before applying mortar. In the case of walls built with a guitar block and brick, as well as in the case of significant unevenness on the surface, it is necessary to apply a thinned plaster (syringe) beforehand. In case of applying mortar to concrete or other smooth surfaces, BK-BetonKontakt should be applied to the substrate in order to improve the adhesion of the mortar. In case of highly absorbent, porous substrates (siporex blocks), a BK-Nivelator should be applied to the substrate to prevent uneven drying and cracking of the mortar. In case of signifi cant surface unevenness. The preparation of the mortar is done by intensive mixing of the powder with about 22-24% of water (7 l of water for 30 kg of product) The mortar is usually applied in two stages, using the fresh-to-fresh method, on previously prepared, dry substrate in thickness of min. 10 mm and max. 25 mm. After that, spread the mortar with an H-shape plastering derby, trim, felt and level. For larger mortar thicknesses it is necessary to apply the mortar continuously according to the fresh-to-fresh principle, up to the required thickness (max. 40 mm).


Substrate and air temperatures from +5°C to +25°C. The mortar must cure evenly. Direct heating of mortar is not recommended. See product datasheet for more detailed instructions.


Approximately 12-13 kg/m²/cm of thickness.


12 months in original packaging in dry room on pallets.


30 kg