Conventional Sand Cement Plaster v/s Ready Mix Plastering

In every construction, plastering is the process after which one can start identifying the exact look and appearance of the structure. It is the process after which mostly decorative and interiors’ works start. Plastering is not a new innovation, it is known to mankind since ages. You must have seen houses where mud is applied on walls. That was one of those earliest forms of plastering.

The key functions of plastering are to provide the following

1. Appearance- It provides a smooth, regular, clean and even surface which is suitable for decorative applications like painting, tiling etc.
2. Protection- Plastering on external masonry surfaces is done to protect the structure from atmospheric conditions and on internal masonry surfaces to protect from dust.
3. Concealing defects- Plastering helps in concealing defects in structure due to alignment like levelling, cracks etc.

Today, in the traditional method of plastering which is prevalent, contractors buy sand and cement from the market and store it on construction site. When required, they mix sand and cement in a fixed proportion along with water to prepare mix which is then applied to the wall to create a plastered surface.

Though it appears very simple, each ingredient has its own importance in terms of requirement and contribution to quality.

Let’s discuss first the role of sand.

Sand is one of the key ingredients which decides the texture, smoothness and compactness of plasters. In geographies like India and current scenario of bans for sand, it is very difficult to obtain the same sand quality during the entire project duration. With the change of source, sand appearance changes. Also, the sand which reaches the market has organic material and silt content in it which impacts the quality of plaster heavily. In the conventional method of plastering, this key aspect of sand is ignored. In general, people ignore if the sand is silt free or organic content free.

For consistent and good quality, sand used during plastering must be free from silt and organic content. Also, the same sand shall be used during the entire project.

Also, one key quality of plaster which provides strength is its compactness. Compactness is directly associated with perfect packing of particles which impacts the strength of plaster significantly. The compactness of plaster is dependent on the right mix of different sizes of a particle in the sand so that it can achieve the maximum compactness. Graded sand plays a key role here. If sand is not graded, the desired compactness of plasters cannot be achieved which will reduce plaster strength significantly.

In Conventional plaster, applicator generally doesn’t go for grading of sand. It finally results in lots of quality issues like cracks, debonding, uneven surfaces.

In India, there are so many different varieties of sand and there is no reliability that same quality of sand will be available in the near future. In general, construction of a house goes for a year and even a few years in case of big projects. Under such a big range of time, maintaining consistent sand quality and type is impractical. Due to storage space constraint at project sites, one cannot buy a complete amount of sand at one time. So to obtain a consistent quality, sourcing of plastering material shall be kept the same to avoid inconsistencies.

Plaster needs to play an important role in providing protection from external weather conditions like raining etc. Excellent weather resistance can add many years to structure’s life. A mix of only sand and cement has limitations in providing a long life to the structure. Advantage of new innovations shall be taken. Special additives and polymers are available in the market which can enhance weather resistance of plasters by enhancing their water resistance capabilities and can add many more years in the life of a structure. These polymerized plasters are more durable than ordinary plasters which directly impacts the maintenance cost in future.

Once bought sand has to be stored on construction. But storage of loose material invites more requirement of storage due to its conical storage and wastage due to spillage. Also, it is exposed to contamination of foreign particles which are in abundance on a construction site. High storage space requirements, wastage of sand due to spillage and contamination can hamper the quality of the project.

In such cases, packed material protects against contamination and spillage and also can be stacked in forms which attract less storage space than loose material.

From the above factors, it is evident that ready-mix plasters provide much better plaster surfaces which are durable and have very low maintenance issues and associated costs than conventional plasters.

Also, quality issues in conventional plaster bring the additional cost of repainting, putty filling, or even re plastering.