Refurbishment of concrete glazed façade

Descripción sistema

During the work to widen Calle Padre Damián in Madrid in the 1960s, the old neo-Mudéjar style church, which stood at the beginning of the street opposite the Santiago Bernabéu stadium, was demolished. The current church was built in its place, designed by the architect Rodolfo García-Pablos González-Quijano (1914-2001). Author of other great Madrid churches in the neighbourhoods of Hortaleza, la Ventilla… The intervention we will show here consists of the restoration and protection of the façade of the Church of the Sacred Hearts, made of concrete stained glass. This type of structure began to be used in 1920 and became popular in the 1950s, being used by great architects and craftsmen all over the world. It creates a spectacular play of light in the interior of the temples.

The use of reinforced concrete offered an alternative to the traditional lead support for stained glass, thanks to its ease of execution compared to lead and the durability it offered.

Description

The façade is cleaned of the dirt deposited, eliminating all possible old coatings in poor condition, for subsequent rehabilitation, maintaining the original aesthetics and characteristics. Proceeding to the recovery of lost or deteriorated volumes, and of the superficial cracking present with high-performance concrete repair mortar. Finally, we proceed to the decorative, waterproof and protective coating against the atmospheric agents present.

This article explains in detail how the rehabilitation of the concrete glazing was carried out, based on the PROPAM® REPAR TECHNO range of mortars and BETOPAINT concrete protection coatings.

Challenges and constraints

“A waterproof and durable coating must be achieved, aesthetically appropriate to the restored architecture and compatible with the characteristics of the façade.
“Cosmetic repair appropriate to the original texture of the concrete, in areas with loss of volume.
“Repair of surface cracks in the concrete glazing.

Molins Solution

“Eliminate cohesionless areas or loose parts.
“Use PROPAM® REPAR TECHNO, a fibre-reinforced mortar with high adhesion, as a mortar for concrete repair and protection of metal reinforcement. It meets the requirements of EN 1504-3, EN 1504-2 and EN 1504-7.
“Use BETOPAINT, a coating of acrylic copolymers in aqueous dispersion, as a waterproof, aesthetic and protective finish for concrete against carbonation, in accordance with the requirements of EN 1504-2.

Execution

“1. First of all, the weak and damaged materials of the façade are completely removed in order to achieve a strong, stable and clean substrate. For this purpose, a pressurised water jet is used to prepare the surface. During this work, weak areas, cracks and spalling are discovered, which must be properly cleaned up and subsequently reconstructed.

” PROPAM® REPAR TECHNO is used to repair the previously treated and cleaned cracks and to recover the volume, which allows us to obtain a smooth finish that is appropriate to the original surface of the concrete glazing. And it allows us to carry out the repair without the need for a bonding bridge, thanks to its high adhesion to the concrete, even on supports that are not very porous.

“Lastly, the stained glass window is prepared for the application of BETOPAINT, protecting the elements that are not going to be painted. With the support clean and properly repaired, a first coat of BETOPAINT is applied with a roller, and when this first coat of primer is dry to the touch, a second coat is applied.

Technical note

The concrete forms a capillary network inside, through which water and different polluting gases from the atmosphere, such as carbon dioxide, can pass. After setting, the water that is retained inside evaporates, forming a network of capillaries which, together with the occluded air bubbles, become a perfect entry point for external agents.

Furthermore, the presence of cracks in the concrete allows water and atmospheric agents to enter the concrete, which, on coming into contact with the reinforcement, promote its oxidation, with the consequent increase in volume due to the formation of iron oxides, leading to new cracks, pitting in the reinforcement, etc., thus increasing the magnitude of the problem even further.

Therefore, regardless of the type of reinforcement used in reinforced concrete, whether stainless or not, the presence of cracks should set off the alarm bells of the technician and promote action to repair them. The proper maintenance of concrete structures is of vital importance for their durability, and within this maintenance it is very important to recover the proper surface condition of the concrete as this is directly related to its durability.

The BETOPAINT and BETOPAINT FLEX range of anti-carbonation acrylic coatings provide adequate protection for concrete structures, both recently executed and after repair work, and are compatible with the range of repair mortars.
with the PROPAM® REPAR range of concrete repair mortars. In addition to meeting the requirements of EN 1504-2 Products and systems for the protection and repair of concrete structures. Part 2: Surface protection systems for concrete.