What is a Chhajja (Sunshade)?
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A chhajja is the projecting RCC slab — the sunshade or weather-shade — cast over a window or door to keep direct sun and driving rain off the opening. It is one of the most common features on an Indian building, usually cast together with the lintel above the opening.
A chhajja is a cantilever
A chhajja is fixed to the building along one edge and projects outward with its far edge free — which makes it a small cantilever. That single fact decides how it is built:
- Under its own weight (and anyone who leans on it), a chhajja hogs — the top face goes into tension.
- So its main reinforcement must be at the top. Put the steel at the bottom and the chhajja has almost no capacity; this is a real cause of sunshade failures.
- The top steel must be anchored well back into the lintel or slab behind it.
The drip mould
The underside of a chhajja usually has a small groove near the outer edge called a drip mould. It breaks the surface tension so rainwater drips off cleanly at the edge instead of running back along the soffit and staining or wetting the wall below the window.
Chhajja vs canopy vs balcony
All three are cantilevers, differing in size and use: a chhajja is the small shade over an opening, a canopy is a larger projecting cover (often over an entrance), and a balcony is a usable projecting floor. The structural principle — main steel at the top — is the same for all.
Frequently asked questions
What is a chhajja in construction? A projecting RCC sunshade or weather-shade cast over a window or door to keep sun and rain off the opening.
Why is chhajja reinforcement placed at the top? Because a chhajja is a cantilever that hogs under load — the top face is in tension — so the steel must go at the top.
What is the drip mould under a chhajja? A small groove near the outer edge of the underside that makes rainwater drip off cleanly instead of running back along the soffit and wetting the wall.
Is a chhajja the same as a lintel? No — the lintel spans the opening and carries the wall above; the chhajja is the sunshade projecting outward, though the two are usually cast together.
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Written and reviewed by practising civil engineers with 10+ years of Indian residential construction experience.