The old façades have some cornice or bandeau ornaments playing a role of decoration as well as water protection in particular. These elements, particularly exposed because of their relief, are often the first to degrade and need to be repaired or replaced quickly to maintain their initial functions. After the elimination of deteriorated elements, this type of restoration presents several difficulties: to reproduce the exact profile of the material as well as its granulometry and to tint the replacement material to find the shade of the original material in order to mask perfectly the restoration.
- Draft template
- Smoothing template
- Protective gloves
- Pitons and brass wire (or galvanized)
- Soft paintbrush
- Prepare the support and the mortar
- Garnish the mortar cornice and pass the smoothing template
Prepare the support and the mortar
1. Before preparing the stone mortar that will be used depending on the nature of the original material, two templates must be provided. The so-called roughing piece, which is 1 cm lower than the finished profile and the other is the finishing or smoothing jig, corresponding in measurement and profile to the original finished material.
2. Once dust has been removed from the location of the material to be reconstituted, attach a frame that will serve as a framework for the selected stone mortar. Use studs and wire in brass or galvanized. Consider the weight generated by the size of the repair to choose the size of the frame and its type of fixation. This frame must be completely covered and embedded in at least 4 cm of mortar. Model it accordingly to the roughing template.
3. When your job site is well prepared, proceed to the development of the exact shade sought after that of the original material. Stain the mortar-stone with either mineral oxides (100 g / bag) or natural coloring earths 300 g / bag. You can do hue tests on a minimal amount of material but offer an exact proportional match that is easy to define. In this type of operation, we must not forget that we can always add dye, but not remove.
Garnish the mortar cornice and pass the smoothing template
1. If necessary, place the guide rails at the base of the cornice as a temporary support for the product on which you will cover the overlapping reinforcement. Leave the surface of the mortar rough for better adhesion of the topcoat.
2. As soon as the first layer stiffens, line the cornice leaving the mortar 1 cm off the finished edge. Lay out the material with the roughing template. Let it become stronger, replenish any gaps, scratch the surface (hooking on the last pass) and then pull the roughing template again.
3. Finish with a product adapted to the grain aspect of the original material (fine, medium or mixture of 2, as necessary). Apply 5 to 10 mm thick in excess of the finish of the original cornice. Then skip the smoothing template. Note that some imperfections may remain visible if they mimic those worn on the original material.
4. Using a soft brush for a smooth or soft metal look for a brushed-scraped look, complete the finish by thoroughly masking the fittings with the old parts. Remember to protect from a flashing the junction of the upper part of the cornice on the wall that supports it. If there is a large length of restored cornice, make splits (perpendicular joints) with the edge of the trowel during firming of the mortar. You will then stop by arranging so they are, but not more, visible than the original joints.
(photos / visuals: © Parexlanko, except special mention)
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- Protection against upwelling by capillarity
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- Making a flashing on ridge
- External Thermal Insulation: Insulating and Coating
- Exterior Thermal Insulation: substrate preparation
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