The granules do not know whether they are indoors or out — but everything around them changes. Exposure, preparation, grain size and the demands on the binder all shift between a living-room wall and an elevation, and treating the two jobs as identical is how one of them disappoints.
What stays the same
The material system: stone dana, binder, primer, trowel. The preparation gospel — cured, dry, sound, clean — governs both (the checklist). And the applicator's hand decides evenness in both places.
What changes
Exposure
An exterior wall lives in UV, driving rain, thermal swing and dust; an interior wall lives with touch, furniture and lamplight. Exterior work therefore leans harder on binder quality and full-system application — the face must shed weather for years (what washability really tests) — while interior work leans on fineness of finish, because everything is seen from a metre away.
Grain
Inside: fine, occasionally medium. Outside: medium to coarse by viewing distance. The full logic is in the grain guide — the short version is that distance forgives coarseness and closeness punishes it.
Water discipline
Outside, the wall itself must be protected: any seepage history gets diagnosed and treated before decorating (texture is not waterproofing). Inside, the discipline is the room's — kitchens and bath splash zones are the wrong rooms for granule finish regardless of product.
Programme
Interiors are small, sheltered, forgiving of a slow careful amateur. Exteriors are large, weather-windowed and unforgiving of stale edges — team jobs, planned around sun and season (why edges rule).
Choosing for a whole house
The common Indian pattern is the sensible one: medium grain on the elevation in a field shade, coarse on the boundary, one fine-grain feature wall inside — three uses of one material family, each sized to its viewing distance. The shade range covers all three from the same catalogue.
Frequently asked questions
Is exterior-grade material different from interior?
The granules are the same stone; systems differ in binder specification for exposure. Buy the system for the location and say which wall it is for when ordering.
Can leftover exterior material be used inside?
Yes — the reverse direction is where caution lives.