Repair and Maintenance Techniques for Building Facades

Sunny Surlaker, Head Technical Services, Assess Build Chem writes on the selection ideologies, materials and methods for defect remediation in Concrete Buildings.

The building façade or the envelope is the primary line of defense against water entering the living spaces. A typical building envelop today consists of:

Combination of RCC Frame and Masonry [CMU, Aerated blocks or Clay Bricks]
RCC only [Aluminium Formwork Cast Walls or Precast Walls]
Combinations of RCC Frame and Glass or Aluminium Glazing

This article covers solutions that are normally seen for the first two types of building façades/envelopes. The most common signs of deterioration seen on RCC/RCC frame/masonry building are:

Biological Growth [Plants / Fungus]
Salt and efflorescence attack
Dampness and wetness [outside to inside or in some cases from wet areas to façade]
Cracks and delamination in plasters and paints / coatings
Leaking and damaged chajjas and wind breakers
Structural deterioration of columns and beams

The concrete structure becomes vulnerable to ingress of water and other aggressive elements due to the action of the mechanisms listed above. These problems can only be identified by being vigilant and by conducting inspections from time to time. Figure 1.

Figure 1: Damages Seen in Structures

If neglected, then the problems manifest into serious defects like spalling concrete, corrosion of reinforcement, and in some cases, the degree of corrosion is so high that the repair becomes structural in nature. Such repairs are normally costly but are necessary for preserving the structure. Reports of maintenance and records should be preserved to determine the suitability as well as the durability of the repair materials. In addition to having knowledge of structural behavior, a rehabilitation expert should also possess thorough knowledge of materials/science not only in terms of advantages but also the disadvantages and the limitations of the materials employed therein. New generation materials and methods in restoring or repairing structures becomes an invaluable part of this idea. Understanding these materials is key to selecting the correct methodologies to address defects in the building structures.