Waterproofing of walls using water-repellent render
ADINOL-DM Waterproofing admixture for mortars and non-reinforced concrete
I. NATURE OF THE PROBLEM – REQUIREMENTS
Due to rain, moisture problems at external walls are a usual phenomenon, which, however, may be confronted easily and effectively from the beginning, during the application of render.
a) The use of MARMOCRET Fine or MARMOCRET Decor decorative, water-repellent, premixed white or colored renders (depending on whether a smooth or coarse wall surface is desired).
b) The use of MARMOCRET-S binder mortar for the preparation of white water-repellent render.
The above mortars offer complete water repellence according to the DIN 18550 standard and at the same time they offer an aesthetically pleasant effect.
The substrate should be free of dust, grease, loose particles etc. and well dampened with water. A traditional spatterdash is then applied, which should be reinforced in tough or very smooth surfaces (e.g. extruded polystyrene boards etc.) with ADIPLAST polymer building latex (cement : sand : ADIPLAST : water = 1 : 1 : 0,25 : 0,25 by volume) in order to improve key bonding of the spatterdash to the above surfaces. Instead of the traditional spatterdash layer, the premixed mortar MARMOCRET-BOND can be used.
Rendering (“Brown coat” – “Floating coat”)
After the spatterdash has dried, a traditional rendering coat is applied (“brown coat”) in order to even out the surface and repair possible imperfections on the wall. Instead of the traditional undercoat layer, the premixed mortar MARMOCRET-BASE can be used.
In case the substrate is made of thermoinsulating layers (polystyrene, polyurethane etc.) as well as on beams, columns, concrete walls, coursing joints etc., reinforcing with fibreglass mesh is recommended during rendering in order to prevent cracking due to increased thermal load imposed on the render around these surfaces and the different contraction-expansion coefficient of the distinct layers.
The fiberglass mesh is lightly pressed on the fresh rendering layer and extends 10-15 cm beyond the covering area of the thermoinsulating boards.
Before applying the render, the render should be well dampened to reduce water immigration from the render mixture to the undercoat. In case colored MARMOCRET Fine or MARMOCRET Decor is used, instead of dampening it is recommended to prime the substrate with PL-PRIMER to reduce absorptivity and secure color uniformity over the whole surface.
Consumption of PL-PRIMER: 40-100 g/m2, depending on the absorptivity of the substrate.
Application of MARMOCRET Fine and MARMOCRET Decor
MARMOCRET Fine or MARMOCRET Decor is added into clean water under continuous stirring, until a mixture with the desired workability is formed. The mixer used must be clean, in order to avoid possible color alteration of the render.
Application of MARMOCRET Fine or MARMOCRET Decor as a finishing (setting) coat of render, at a thickness of approx. 5 mm. The render may be applied with a float or trowel or by using a plastering machine.
Consumption of MARMOCRET Fine: approx. 7,5 kg/m2/5 mm of render thickness.
Consumption of MARMOCRET Decor: approx. 10 kg/m2/5 mm of render thickness.
The surface should be rubbed with a sponge float (when MARMOCRET Fine is applied) or a spiked float (when MARMOCRET Decor is applied) after sufficient setting has occurred.
Application of MARMOCRET-S
The content of one 15 kg bag of MARMOCRET-S should be mixed with approx. 70 kg of fine marble aggregates and 18 kg of water. The mixer used must be clean, in order to avoid possible color alteration of the render.
Application of MARMOCRET-S as a finishing (setting) coat of render, at a thickness of about 5 mm. The render may be applied with a float or trowel or by using a plastering machine.
Consumption of MARMOCRET-S: approx. 1,5 kg/m2/5 mm of render thickness (for the above mixing proportions).
The surface should be rubbed with a sponge float after sufficient setting has occurred.
During the application of the render, the temperature must be at least +50C.
During the summer months, it is recommended that the render is dampened after its application, in order to be protected from dehydration due to high temperature.