---
title: How to Specify Rooftop Plant Screens (Visual Screening)
url: https://www.koyda.com/guides/plant-screens-specification/
description: Specifying visual plant screens: planning conditions, wind load to BS EN 1991-1-4, free area, fixing without damaging the roof, finishes and access doors.
last_modified: 2026-10-10
publisher: Koyda Ltd, Units 27–29 Jesmor Farm, St Piers Lane, Lingfield, Surrey RH7 6PN. 07753 213617, joe@koyda.com
---

Technical guide

# How to Specify Rooftop Plant Screens

A visual plant screen hides rooftop plant from view, usually to meet a planning condition. To specify one, you need the planning requirement, the wind load, the free area the plant needs, and how it fixes to the roof.

Last reviewed 10 October 2026 · Koyda Ltd

## Key points

* This guide covers visual screens only. Acoustic screens are a separate specialist design, and Koyda does not supply them.
* Wind load is calculated to BS EN 1991-1-4 and its UK National Annex. It depends on location, height, terrain and how solid the screen is.
* Agree the free area (open percentage) with the M&E designer, so the plant can still take in and exhaust air.
* If the screen also acts as edge protection, it must be designed as a barrier as well.

## Planning

Screens are often required by a planning condition. Many conditions need the details approved before installation, so allow time to submit drawings and get the condition discharged. See the government's guidance on planning conditions.

## Screen types

* Vertical bars or blades (steel or aluminium)
* Horizontal louvres
* Perforated or expanded mesh panels

## Design inputs

* **Wind:** to BS EN 1991-1-4. Rooftop screens see higher wind speeds than screens at ground level, and corners and edges carry the highest pressures.
* **Free area:** the M&E designer confirms how much open area the plant needs for airflow.
* **Height and line:** set from the planning drawings, so the plant is hidden from the agreed viewpoints.
* **Access:** doors or removable panels for maintenance and plant replacement.

## Fixing to the roof

There are three options: posts fixed to the structure, a steel frame spanning between structural points, or a ballasted system. Every penetration through the roof needs a detail agreed with the roofing contractor, so the waterproofing warranty is not affected. Check that ballasted systems are stable against overturning and sliding in wind.

## Finishes and earthing

Hot-dip galvanising to BS EN ISO 1461 with a powder coat suits steel screens. Aluminium can be powder coated or anodised. Metal on a roof may need bonding to the lightning protection system, so check with the lightning protection designer (BS EN 62305).

## Checklist

* The planning condition and the approved drawings
* Wind design basis and who does the calculations
* Free area agreed with the M&E designer
* Fixing method and roof interface details
* Access doors; finish and colour (RAL)
* Visual screening only: acoustic performance is excluded

## Sources

1. [Use of planning conditions (GOV.UK planning practice guidance)](https://www.gov.uk/guidance/use-of-planning-conditions)
2. BS EN 1991-1-4 Wind actions and UK National Annex (BSI)
3. BS EN ISO 1461 Hot-dip galvanized coatings (BSI)
4. BS EN 62305 Protection against lightning (BSI)

General guidance only, not design advice for a specific project. Check the current edition of each document.

ContentsGuide

1. [Planning](#planning)
2. [Screen types](#types)
3. [Design inputs](#design)
4. [Fixing to the roof](#fixing)
5. [Finishes and earthing](#finish)
6. [Checklist](#checklist)

Related servicesKoyda

* [Plant Screens](https://www.koyda.com/services/plant-screens/)
* [Structural Steel](https://www.koyda.com/services/structural-steel/)

[Send drawings →](https://www.koyda.com/contact-us/)

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