# Perforated Metal Facade Screens and Solar Shading

> A perforated metal facade screen is sheet metal, usually aluminium, punched with a repeating pattern of holes and formed into panels or cassettes hung in front of glazing or a solid wall for shading, screening and appearance. Its key variable is the open area percentage, which trades solar shading against view and daylight.

## What it is

Sheet metal — usually aluminium, sometimes stainless or weathering steel —
**punched with a repeating pattern of holes** and formed into panels or
cassettes, hung in front of glazing or a solid wall.

It does three jobs at once: shading, screening and appearance.

## Specification at a glance

| Property | Typical specification |
| --- | --- |
| Material | Aluminium to IS 737, or stainless / Corten |
| Thickness | 2mm — 4mm typical for panels |
| Perforation | Round, square, slot, or bespoke pattern |
| Open area | Stated as a percentage — the key variable |
| Edge margin | Unperforated border for stiffness and fixing |
| Finish | PVDF powder coat or anodised |

## What the screen achieves

**Solar shading without blocking the view.** Because the screen sits in front
of the glass with a gap, it intercepts direct sun before it reaches the
glazing, while occupants still see out through the perforations.

**Glare control** on east and west elevations where low sun defeats overhangs.

**Privacy** at close-facing elevations, working in one direction because of the
brightness difference between inside and outside.

**Plant and car park screening**, concealing equipment while allowing the
ventilation those spaces need.

## Where projects go wrong

- **Open area chosen visually**, not against sun path and daylight needs.
- **Wind load assumed negligible** because the panel is perforated.
- **No unperforated margin**, so the panel has no stiffness at its edges and
  distorts at the fixings.
- **Panels rotated on site** where the perforation pattern or image has a
  defined orientation.
- **Cleaning and maintenance access not considered.** A screen in front of glass
  makes the glass much harder to clean, and that has to be planned.

## Standards referenced

Aluminium sheet under **IS 737**. Shading and SHGC provisions under
**ECBC 2017**. Wind loading on cladding and screens under **IS 875 (Part 3)**.

## Frequently asked questions

### What open area percentage should be specified?

It is the key variable and it trades shading against view and daylight. Roughly 20 to 30 percent open gives strong solar shading and privacy while remaining visually open from inside; 40 to 50 percent lets through more light and view with less shading benefit. It should be chosen per elevation against the sun path rather than applied uniformly around the building.

### Do perforated screens reduce wind load?

They reduce it compared with a solid panel of the same size, but they do not eliminate it, and the reduction is not simply proportional to open area. Wind load on a perforated screen and on the structure behind it must be assessed properly under IS 875 Part 3. Treating a screen as weightless because it has holes in it is a structural error, particularly at height.

### Can images or patterns be perforated into panels?

Yes. Varying hole size and spacing across a panel reproduces a gradient or an image that reads at distance and dissolves into pattern close up. It is a common feature treatment on car park facades and institutional buildings. It costs more because the tooling and programming are bespoke, and panel orientation becomes critical since a rotated panel breaks the image.

## Sources

- [IS 737](https://standards.bis.gov.in/website/published-standards/department-wise) — Wrought aluminium alloy sheet and strip
- [ECBC 2017](https://beeindia.gov.in/) — Building envelope — shading and SHGC
- [IS 875 (Part 3)](https://standards.bis.gov.in/website/published-standards/department-wise) — Wind loads on buildings

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Source: https://hagerstone.com/materials/perforated-metal-facade-screen