Demystifying the Common Myths Around Gypsum Plastering

Gypsum plastering, despite its rapid adoption in India, is still surrounded by myths and misconceptions — often perpetuated by contractors unfamiliar with the material or by those with commercial interests in conventional cement plastering. Here we address the most common myths with clear facts.

Myth 1: "Gypsum plastering is not durable"

Fact: Gypsum plaster is extremely durable in its correct application environment — interior walls and ceilings. Gypsum has been used as a plastering material for over 5,000 years. The interior plasterwork in Egyptian pyramids and Roman buildings that used gypsum is still intact today. Modern gypsum-plastered walls, correctly applied and kept dry, last the lifetime of the building — 25+ years without significant deterioration.

The myth of poor durability typically arises from cases where gypsum was incorrectly applied to exterior or moisture-exposed surfaces, which it is not designed for.

Myth 2: "Gypsum gets damaged by humidity in India"

Fact: Gypsum is indeed sensitive to sustained water exposure or direct wetting — which is why it should not be used on exterior walls or in wet areas like bathrooms. However, normal indoor humidity levels in India (even in coastal cities or during monsoon) do not damage correctly applied and painted gypsum plaster. The paint and primer form a protective seal. Millions of gypsum-plastered homes in Chennai, Kochi, and Mangalore — high-humidity coastal cities — are performing well with no moisture-related issues.

The key distinction is between normal ambient humidity (fine) and direct water exposure or seepage (not suitable). Address any water seepage before plastering, and gypsum will perform well.

Myth 3: "Gypsum plastering is more expensive"

Fact: This is the most persistent and most misleading myth. When compared only on material cost per bag, gypsum may appear similar in price to cement. But a fair comparison must include: no putty required (₹8–15/sq ft saving), no curing cost, faster labour completion, and shorter project timeline. The total cost of gypsum plastering is approximately 20% lower than sand cement + PoP.

Myth 4: "You cannot use gypsum on AAC blocks"

Fact: Gypsum plaster is fully compatible with AAC (autoclaved aerated concrete) blocks. In fact, gypsum is often preferred for AAC because its lower density and similar thermal coefficient reduce the risk of cracking at the block surface. A bonding agent or primer coat may be recommended for the first application, after which gypsum adheres excellently. AAC blocks with gypsum plastering is one of the most commonly specified combinations in modern construction.

Myth 5: "Gypsum cannot be used for ceilings"

Fact: Gypsum plaster is routinely and successfully applied to RCC slabs (ceilings). The correct thickness is 8mm (vs 11mm for walls). Properly mixed and applied, gypsum ceiling plaster achieves excellent adhesion and a smooth finish. Gypsum boards (Gyproc) are also the standard material for false ceilings. This myth likely originates from early attempts to apply gypsum at incorrect thickness or without proper surface preparation.

Myth 6: "Gypsum plastering needs special paint"

Fact: Gypsum is a very forgiving surface. Any quality primer followed by any standard interior paint — emulsion, distemper, texture paint, or wallpaper — can be applied to gypsum-plastered walls. The only requirement is that a primer is applied before the topcoat, which is standard practice regardless of the substrate. No special gypsum-specific paint is required.

Myth 7: "Gypsum plastering cracks more than cement"

Fact: The opposite is true. Gypsum does not shrink during setting — it actually undergoes a slight expansion. This means no shrinkage cracks, which are the most common cause of cracking in cement-plastered walls. Cracks in gypsum-plastered buildings, when they do occur, are typically caused by structural movement or seepage — the same causes as in any well-plastered surface.