How do shading devices function at different elevations (walls vs roofs) in tropical design?

• A. Roof shading (overhangs/eaves) blocks midday sun; wall shading (screens/brise-soleil) reduces high-angle sun and improves visual comfort; both maintain daylight.
• B. Roof shading is ineffective; only walls matter.
• C. Both approaches are necessary to maintain daylight and comfort, with roof shading handling midday sun and wall shading addressing high-angle sun.
• D. Shading devices only affect heat, not daylight.

Answer: (C)

In tropical design, shading needs to be applied at multiple elevations because sun angles change throughout the day and affect surfaces differently. A roof overhang or eave is sized to intercept the sun when it is high in the sky, especially around midday, so direct radiation is blocked before it reaches the interior and roof/ceiling areas. This keeps spaces cooler and reduces heat gain while still allowing diffuse daylight to enter.

Shading devices on walls—like screens, brise-soleil, or louvers—block direct sun from hitting façades when the sun is at oblique angles earlier and later in the day. They cut down on heat gain through windows and walls and also reduce glare, while still letting in natural light.

Using both approaches together is essential because relying on only one leaves gaps in solar control: roof shading handles the midday, high sun, while wall shading manages the sun at other angles. With both, you maintain daylight and improve thermal comfort.