Restoration of old façade with REVAT® CAL® range lime mortars

Descripción sistema

Work on the complete façade of a residential building located in Calle Ferraz in the historic district of Argüelles in Madrid. Calle Ferraz dates back to the mid-19th century and suffered severe devastation during the war, which led many of its buildings to undergo various reconstructions and subsequent repairs.

Description

All of the old and dilapidated coverings were removed for subsequent restoration, maintaining the original aesthetics and characteristics. The uncovered support is mainly made up of a mixture of ceramic materials from different periods. During the restoration work, considerable loss of volume occurred in some areas of the façade, mainly in the lintels and the sills of balconies and windows.

This article explains in detail how the rehabilitation of the façade has been carried out, based on the REVAT® CAL mortar range.

Challenges and constraints

“The cladding must be waterproof and durable, aesthetically appropriate to the architecture of the area and compatible with the characteristics of the façade.
“The presence of old areas, possibly from the end of the 19th century, and more modern areas from the second half of the 20th century, requires the use of compatible and suitable materials for these supports.
“Reconstruction of lost volumes and recovery of the planimetry of the façade which, after the restoration work, has been badly damaged; in some areas it is necessary to recover up to 6 cm of the original volume.

Molins Solution

“Eliminate cohesionless areas or loose parts.
“For weak, friable or powdery areas, use PROPAM® DUR to improve the consolidation of the substrate.
“Use REVAT® CAL MURO (G-M5 according to EN 998-2) as a masonry mortar for restoration and reconstruction of the lost masonry.
“Apply REVAT® CAL FONDO (GP-CSII-W0 according to EN 998-1) as a bonding mortar and surface levelling mortar once the facade has been repaired. Reinforced with REVAT 110 fibreglass mesh.
“Apply REVAT® CAL ENFOSCADO (GP-CSII-W2 according to EN 998-1), as a water-repellent finishing coat, finishing with a scraped finish.

Elements of the system

Execution

“First of all, the weak materials and those in poor condition of the façade are completely eliminated, in order to achieve a resistant, stable support, free of the remains of old plaster, paint, efflorescence, etc. During this work, very weak areas are discovered that must be cleaned up in depth and elements that have lost the mortar that supported them, and must be reconstructed.

“For weak, friable or powdery areas, PROPAM® DUR should be applied with a brush and left to act for a minimum of 24 hours. It is a liquid consolidant based on solvent-based resins, with a high penetrating power, suitable for all types of mortar surfaces with a tendency to surface disintegration. It recovers surface cohesion and guarantees adhesion in the following stages.

“For the recovery of volumes, REVAT® CAL MURO (G-M5 in accordance with EN 998-2) is used as a lime-based mortar for the recovery and reconstruction of the lost masonry. The ceramic elements detached during the repointing of the façade are replaced and the lost volumes are complemented with new ceramic tiles.

“Once the façade plane has been recovered, REVAT® CAL FONDO is applied as a bonding and levelling mortar. This allows the final finishing coat to be applied later. The surface made up of materials of different natures and periods is thus uniform. This layer is reinforced with REVAT® 110 FIBRE GLASS MESH and metal mesh anchored to the substrate. The surface of this layer is roughened to facilitate the anchoring of the final finishing layer.

” 5. Once the previous coat of REVAT® CAL FONDO has hardened, apply the REVAT® CAL ENFOSCADO mortar as a water-repellent finishing coat, proceeding after a few hours of drying to carry out the finishing by scraping. Decorative and working sections are made on different parts of the façade.

Current appearance of the façade compared to the original appearance

Technical note

Faced with the challenges of refurbishing old buildings, where we find façades that mix substrates from very different eras, modern prefabricated lime mortars offer performance that combines the tradition and performance of old lime mortars with the best modern technologies in the manufacture of façade cladding.

Lime mortar, or prefabricated lime mortar, is nowadays a mortar with ideal mechanical and breathability characteristics for both old buildings and new construction. It performs exceptionally well on heterogeneous substrates such as old masonry with mixtures of stone, ceramic, wood, etc. and also provides excellent performance on the most modern and new construction substrates.

The REVAT® CAL range of mortars, manufactured with aerial lime, provides high breathability to the facades. They achieve high levels of waterproofing and resistance to climatic cycles. They allow to obtain traditional finishes such as Tyrolean, hammered, swirled or smooth and other more modern finishes such as scraped finishes. In addition, the use of the REVAT® CAL range on façades favours the breathability of the wall, thanks to its high water vapour permeability, improving comfort and indoor air quality.